Abstract: This data layer shows the generalized lithologic and geochemical (lithogeochemical) character of near-surface bedrock in the Connecticut, Housatonic, and Thames River Basins and several other small basins that drain into Long Island Sound from Connecticut. The area includes most of Connecticut, western Massachusetts, eastern Vermont, western New Hampshire, and small parts of Rhode Island, New York, and Quebec, Canada. Bedrock geologic rock formations are classified into 29 lithogeochemical rock units, based on the relative reactivity of their constituent minerals to dissolution and other weathering reactions and the presence of carbonate or sulfide minerals. The 29 lithogeochemical units can be summarized into 6 major categories: (1) carbonate-rich rocks, (2) carbonate-poor, clastic sedimentary rocks restricted to distinct depositional basins, (3) metamorphosed, clastic sedimentary rocks (primarily noncalcareous), (4) mafic igneous rocks and their metamorphic equivalents, (5) ultramafic rocks, and (6) felsic igneous and plutonic rocks and their metamorphic equivalents. Lithogeochemical rock units also are grouped into nine lithologic and physiographic provinces (lithophysiographic domains), which can be summarized into three major regions: (1) western highlands and lowlands, (2) central lowlands, and (3) eastern highlands.
Purpose: This data layer was compiled to provide the U.S. Geological Survey's National Water Quality Assessment (NAWQA) Program's study of the Connecticut, Housatonic, and Thames River Basins with digital geologic information that could be applied to the analysis of water-quality characteristics of surface water and shallow ground water. Goals of the NAWQA program are to describe the status and trends of a large representative part of the Nation's surface- and ground-water resources and to identify the natural and human factors that affect the quality of these resources (Leahy and others, 1990). The data set presented here was intended to characterize the bedrock geologic units in the Connecticut, Housatonic, and Thames Basins study area in terms of mineralogic and chemical characteristics relevant to water quality, such that the geologic data exists in digital form and could be used in a Geographic Information System (GIS) to analyze and interpret water-quality and ecosystem conditions.
Supplemental Information: Procedures_Used: The data layer was compiled from State and regional geologic maps. Most of the data layer was compiled on scale-stable (mylar) sheets based on the available State-wide bedrock geologic map sources: sheet 1, Connecticut; sheet 2, Massachusetts and adjacent parts of New York; sheets 3-6, New Hampshire and Vermont. For sheet 1, base compilation materials were prepared at 1:125,000 scale from scale-stable negatives used in the printing of the bedrock map of Connecticut (Rogers, 1985). For sheet 2, a paper copy of the bedrock map of Massachusetts (Zen and others, 1983, compiled at 1:125,000 but published at 1:250,000) was photoenlarged to 1:125,000 scale and registered to a cartographic base because the scale-stable cartographic materials used to print Zen and others (1983) were not available. The Massachusetts source map also included a small part of New York that was in the study area. For sheets 3-6, geologic-unit contacts from the New Hampshire and Vermont State maps and regional maps (Billings, 1955; Doll and others, 1961; Moench, 1984; Lyons and others, 1986) were hand-fitted to the cultural and topographic features on enlarged (1:125,000 scale) greenline mylar parts of the 1:250,000 scale U.S. Geological Survey (USGS) Albany, Glens Falls, Champlain, Sherbrooke, Lewiston, and Portland topographic quadrangles; these contacts were drawn and digitized at 1:125,000 scale. For Rhode Island and parts of New York adjacent to Connecticut, source materials of the State geologic maps were available as digital data layers (Fisher and others, 1970, 1:250,000 scale, New York; Hermes and others, 1994, 1:100,000 scale, Rhode Island). The geologic units shown on the State and regional bedrock geologic maps were classified according to a lithogeochemical coding scheme, described below (see the "Notes" section of this document). Classification of the specific bedrock geologic units was based primarily on descriptions of the lithology, mineralogy, and weathering characteristics (for example, "rusty-weathering" as an indicator of sulfidic-bearing units) provided on the maps. In the Mesozoic Basin of Connecticut and Massachusetts, data from Smoot (1991) were used to modify the contacts and descriptions shown on the State maps. A table listing the codes assigned to individual geologic map units arranged by State is provided in the "Notes" section of this document. Polygons defining the coded geologic units were digitized in map units from the 1:125,000 mylar sheets. For Massachusetts and Connecticut, adjacent geologic units receiving the same lithogeochemical code in most cases were combined into larger polygons during digitizing (some boundaries separating map units with the same lithogeochemical code but different lithophysiographic-domain codes also were digitized). For New Hampshire and Vermont, boundaries between geologic map units receiving the same lithogeochemical code and some major fault lines were digitized. This resulted in more lines than strictly necessary to define the lithogeochemical boundaries. However, the additional lines do not detract from the potential interpretative uses of the data layer and can be selected out (see arc or ".AAT" attribute "bnd_type") if necessary. For small parts of Rhode Island and New York (west of Connecticut), the digital source materials were directly coded using the source data-layer attribute information. For Quebec, Canada, parts of the regional geologic map of Moench and others (1995), 1:250,000 scale, were digitized and lithogeochemical codes were added to the digitized coverage. The separate digitized State coverages were clipped using digitized State borders from 1:24,000-scale USGS topographic quadrangles (except the border between Vermont and New Hampshire, which is from digitized 1:100,000-scale USGS topographic quadrangles). At this point, an attribute was added to identify the State within which each polygon is located. Quality-assurance procedures involved plotting linework and shaded polygons onto mylar at the same scale and projection as the mylar source sheets. The plots were overlain on the source sheets and compared to the State geologic maps to check for accuracy of digitized linework and polygon attributes. For Massachusetts, two separate mylar plots were made for the east and west parts of the source sheet to account for the two central meridians of the two USGS topographic quadrangles used as the base of the Massachusetts geologic map (Zen and others, 1983; see the "Use_Constraints" section of this document). At least four iterations of plotted linework and polygon shading were checked for each State. After potential errors associated with polygon labels and line junctions were checked (using the "labelerrors" and "nodeerrors" commands of ARC/INFO), the digitized State lithogeochemical data layers were combined (using the "mapjoin" command of ARC/INFO) into a single data layer covering the entire study area. State boundaries (see arc or ".AAT" attribute 'bnd_type') and the State-location attribute were maintained in the combined data layer. The State-location attribute will help clarify the remaining discrepancies associated with the various geologic-map source materials (see the "Use Constraints" section of this document for additional information). The study-area-wide data layer was further evaluated for consistency of coding of similar rock units in adjacent States and at State boundaries. Final node and label checking were performed and arcs defining small "sliver" polygons were removed (using the "unsplit" command of ARC/INFO) to further correct the data layer. Reviews_Applied_to_Data: This document was revised in response to technical reviews by Stephen J. Grady, Hydrologist, USGS, Water Resources Division, Hartford, CT; Thomas P. Frost, Geologist, USGS, Geologic Division, Spokane, WA; John W. Brakebill, Geographer, USGS, Water Resources Division, VA; and Bruce Warklow (geologic names), USGS, Geologic Division, Reston, VA; and in response to an editorial review by Linda S. Rogers, Publications Chief, USGS, Marlborough, MA. ***Related_Spatial_and_Tabular_Data_Sets: This data layer may be retrieved as an ARC/INFO export file or as a spatial data transfer format (STDF) file. The following associated files also may be retrieved. ***(1) Postscript files, designed to be printed on large-format plotters. Separate files show the lithogeochemical units and lithophysio- graphic domains in the study area. ***(2) Bitmap-image files. These files also show the lithogeochemical units and lithophysiographic domains in the study area. These images can be graphically displayed and draped behind other GIS data that is located in the same spatial domain. A World Wide Web page summarizes many of the details described in this metadata document and contains all of the files described in this section. Below are the CMYK (cyan, magenta, yellow, black) percent shade values for each lithogeochemical rock type as it appears on plate 1 of 2: > >Rock Type C M Y K >---------------------------- > 12 20 10 50 0 > 12s 40 20 15 0 > 13 70 0 0 0 > 21 0 40 0 0 > 21cs 20 40 60 0 > 22 0 0 35 0 > 23 30 10 10 0 > 31 0 0 0 20 > 31s 0 10 10 0 > 32 0 20 30 0 > 32c 40 0 10 0 > 32s 10 100 100 0 > 32cs 0 60 70 0 > 33 10 50 20 0 > 33c 40 50 0 0 > 33s 20 100 50 0 > 34 0 0 80 0 > 34c 10 0 70 0 > 35 0 20 0 0 > 41 80 0 70 0 > 42 40 0 100 0 > 43 20 0 40 0 > 44 50 0 40 0 > 50 20 60 0 0 > 50c 80 30 0 10 > 61 0 10 30 0 > 61v 20 50 100 0 > 62 30 60 100 0 > >Below are the CMYK percent shade values for each lithophysiographic domain as it appears on plate 2 of 2: > >Domain C M Y K >---------------------------- > T 60 20 30 0 > S 30 7 7 0 > Y 40 0 40 0 > H 0 14 27 0 > N 40 70 80 0 > C 20 40 70 0 > B 14 56 16 0 > M 20 90 40 0 > Z 0 80 80 0 > Other_References_Cited: Sources of Map and Geologic Data. Billings, M.P., 1955, Geologic Map of New Hampshire: Reston, VA, U.S. Geological Survey, 1:250,000. Doll, C.G., Cady, W.M., and Thompson, J.B., Jr., and Billings, M.P., eds. and compilers, 1961, Centennial Geology Map of Vermont: Montpelier, VT, U.S. Geological Survey, 1:250,000, 1 sheet. (transverse mercator projection, based on best available information). Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., eds., 1970, Geologic Map of New York, Lower Hudson Sheet: New York State Museum and Science Service, Map and Chart Series No. 5, 1:250,000 (UTM projection). Hermes, O.D., Gromet, L.P., and Murray, D.P., 1994, Bedrock Geologic Map of Rhode Island: Kingston, RI, Office of the Rhode Island State Geologist, Rhode Island Map Series No:1, scale 1:100,000, 1 sheet (transverse mercator projection, zone 19). Leahy, P.P., Rosenshein, J.S., and Knopman, D.S., 1990, Implementation plan for the National Water-Quality Assessment Program: U.S. Geological Survey Open-File Report 90-174, 10 p. Lyons, J.B., Bothner, W.A., Moench, R.H., and Thompson, J.B., Jr., 1986, Interim Geologic Map of New Hampshire: Reston, VA, U.S. Geological Survey, 1:250,000, 1 sheet (Lambert conformal conic projection, standard parallels 33 and 45 degrees). Moench, R.H., ed., 1984, Geologic maps of the Sherbrooke-Lewiston Area, Maine, New Hampshire, and Vermont: U.S. Geological Survey Open-File Report 84-0650, 1:250,000. Moench, R.H., Boone, G.M., Bothner, W.A., Boudette, E.L., Hatch, N.L., Jr., Hussey II, A.M., and Marvinney, R.G., 1995, Geologic map of the Sherbrooke-Lewiston Area, Maine, New Hampshire, and Vermont, United States, and Quebec, Canada: U.S. Geological Survey Miscellaneous Investigations Series Map I-1898-D, 1:250,000, 2 sheets (transverse mercator projection). Rogers, J., 1985, Bedrock geological map of Connecticut: Hartford, Conn., Connecticut Geologic and Natural History Survey, 1:125,000, 2 sheets (polyconic projection, zones 18 and 19). Smoot, J.P., 1991, Sedimentary facies and depositional environments of early Mesozoic Newark Supergroup basins, eastern North America: Paleogeography, Paleoclimatology, Paleoecology, v. 84, p. 369-423. Zen, E-an, Goldsmith, G.R., Ratcliffe, N.L., Robinson, P., and Stanley, R.S., 1983, Bedrock geologic map of Massachusetts: Washington, D.C., U.S. Geological Survey, 1:250,000, 3 sheets. Notes: (A) DEVELOPMENT AND DESCRIPTION OF THE LITHOGEOCHEMICAL CLASSIFICATION SCHEME: A wide variety of igneous, metamorphic, and sedimentary rocks with varying types and thicknesses of overlying surficial materials are present in the Connecticut, Housatonic, and Thames River Basins. The rock types are described on bedrock geologic maps at scales of 1:250,000 to 1:100,000 that are available for the six States in the study area. These maps collectively contain nearly 600 mappable rock units, which are defined by time-stratigraphic and other geologic criteria that may not be directly relevant to water quality. Moreover, the rock units depicted on the State geologic maps are inconsistent across State boundaries in some areas. Thus, a study-area-wide coding scheme was developed to classify the geologic map units according to mineralogical and chemical characteristics that are relevant for water-quality investigations. Rock types may be classified for water-quality purposes according to the chemical composition and relative susceptibility to weathering of their constituent minerals. Although climatic, geologic, geochemical, biochemical, and anthropogenic factors all influence water quality, reaction with rock and soil minerals through weathering reactions is a principal source of major and trace constituents of most natural waters. Consequently, the chemical character of soil water, surface water, and shallow ground water in a drainage basin often is similar (Vebel, 1985; White, 1995, p. 438-440), and the chemical compositions of the natural waters and the rock types with which they are in contact are related (Rose and others, 1979, p. 352-354). Among water-quality characteristics potentially affected by weathering reactions are the total dissolved-solids concentrations, relative concentrations of most major dissolved ions (calcium, magnesium, sodium, potassium, sulfate, and bicarbonate), pH, hardness, alkalinity, acid-neutralizing capacity, and redox conditions. Although weathering rates may vary, the relative stability of different minerals during weathering in moist climates generally is consistent. The observed relative stability of common rock-forming silicate minerals in chemical weathering in temperate humid climates by Goldich (1938) is, in order of increasing stability: olivine < augite < hornblende < biotite < potash feldspar < muscovite < quartz; and calcic plagioclase < calc-alkalic plagioclase < alkali-calcic plagioclase < alkalic plagioclase < potash feldspar < muscovite < quartz. This arrangement is similar to Bowen's reaction series, which defines the order of successive mineral formation during magmatic crystallization (Bowen, 1922); minerals that crystallize earlier in the sequence are more readily weathered. Most igneous rock types (and metamorphic rock types with similar mineral assemblages) are described and defined according to the presence and relative abundance of these minerals. Thus, igneous and metamorphic rocks can be arranged on this basis into a lithogeochemical classification scheme that reflects their relative weatherability. Sedimentary rocks contain many of the same minerals as igneous and metamorphic rocks, as well as carbonate minerals and secondary minerals such as clays, oxides, and hydroxides. Jackson and others (1948) determined a weathering sequence for fine-grained minerals in soils that includes these minerals (in order of increasing stability): gypsum (and halite and other salts) < calcite (and dolomite, aragonite, etc.) < olivine-pyroxene-hornblende < biotite (and chlorite, etc.) < albite (and anorthite, microcline, etc.) < quartz < illite (muscovite) < hydrous micas-clays < Al-hydroxides < Fe-Ti oxides and hydroxides. This sequence reflects the rapid dissolution in water of salts, gypsum (and other soluble sulfate minerals), and to a lesser degree carbonate minerals. Plagioclase and ferromagnesian minerals, such as olivines, pyroxenes, amphiboles, and to a lesser degree biotite, are less soluble than salts and sulfates but are weathered more rapidly than alkali-feldspars, muscovite, or quartz, which are relatively inert and insoluble. Most igneous, metamorphic, and sedimentary rocks are complex mixtures of minerals. The effects on water quality of contact with any particular rock type depend on the rock's mineralogical and chemical composition and its "weatherability." A rock's "weatherability" reflects the relative proportions of its constituent minerals as well as other factors, such as its degree of induration and the relative amount of mineral surfaces exposed to water through its primary and secondary porosity, which, in turn, are caused by joints, fractures, and dissolution. Thus, although ultimately based on the relative stability of rocks' constituent minerals, classification schemes to group rock types according to their effect on water quality are less determinate and more complex than the mineral-stability sequences. Moreover, most common rock-forming minerals are only sparingly soluble, so that small amounts of highly reactive minerals can have large effects on water quality. For example, the presence of carbonate minerals is an important factor in humid temperate climates, where rocks rich in carbonate minerals and clastic rocks cemented by carbonates are more rapidly weathered and tend to produce higher solute concentrations in natural waters than other rock types. In contrast, granites, schists and quartzites, which are similarly rich in alkali-feldspar, muscovite, and quartz, produce lower solute concentrations because they react to a lesser degree and at slower rates than other rock types in humid temperate climates. Several classification schemes relating the composition of natural waters to the bedrock geology of the source area have been developed (see Garrels, 1967; Garrels and MacKenzie, 1967; White and others, 1963), but none is definitive (Hem, 1989, Clarke, 1924, p.8). White and others (1963) described ground waters of low solute concentration by association with 11 common rock types: (1) granite, rhyolite, and similar types, (2) gabbro, basalt, and ultramafic rocks, (3) andesite, diorite, and syenite, (4) sandstone, arkose, and graywacke, (5) siltstone, clay, and shale, (6) limestone, (7) dolomite, (8) quartzite, (9) marble, (10) slate, schist, and gneiss, and (11) unconsolidated sands and gravels. Amiotte-Suchet and Probst (1993) found that solute fluxes and rates of chemical weathering in 200 small monolithologic drainage basins in France were significantly different when the drainage basins were grouped according to to seven lithologic categories (in order of decreasing solute contribution): (1) evaporites, (2) carbonate rocks (limestone, dolomite, chalk, and marl), (3) argillaceous rocks (clays, shale, slate), (4) basalt, (5) sandstone, arkose, and graywacke, (6) felsic volcanic rocks (rhyolite, andesite, and (7) plutonic and metamorphic rocks (granite, gneiss, and schist). Bedrock lithologic classification schemes also have been used to evaluate the effects of acid deposition on ecosystems. Glass and others (1982) classified rocks in New York State into four groups according to their ability to neutralize acid deposition: (1) granite, syenite, granitic gneiss, quartz sandstone, or equivalents (low or no buffering capacity); (2) shales, sandstones, conglomerates, high-grade metamorphic to intermediate volcanic rocks, intermediate igneous rocks, and calc-silicate gneisses (low to medium buffering capacity); (3) slightly calcareous, low-grade intermediate to mafic volcanic, ultramafic, and glassy volcanic rocks (medium to high buffering capacity); and (4) highly fossiliferous sediments or metamorphic equivalents, limestones, dolomites (very high buffering capacity); the purpose of the work by Glass and others was to identify regions most sensitive to acid deposition on a State-wide basis. Similar types of regional lithogeochemical mapping has been done in the southern Appalachians, where acid-base status is a critical factor in maintaining ecosystem structure in upland forested basins. In the southernmost Blue Ridge Physiographic Province (east side) of Maryland, Bricker and Rice (1989) noted bedrock lithologic controls by rock type (granite, greenstone, quartzite, phyllite, and limestone) on stream-water quality and acidification in basins. Webb and others (1994), studying trout streams in the Virginia Blue Ridge, Valley and Ridge, and Plateau Physiographic Provinces, classified bedrock type into high, medium, and low acid-neutralizing capacity by relating stream-water chemistry to bedrock type. This classification scheme was used to generate a map showing predicted sensitivity to acid deposition for stream waters in southern Appalachian Mountain basins (Peper and others, 1995). The lithogeochemical classification scheme used in this data layer incorporates the observed relative stability of minerals, described above, classification criteria such as used in the cited previous studies, and characteristics of bedrock geology of the study area (such as the presence of a distinct sedimentary basin, the Mesozoic Basin in Connecticut and Massachusetts). The lithogeochemical classification scheme consists of 29 rock types (28 types occur in the study area) that are based on weatherability and the presence of carbonate and sulfide minerals. Carbonate and sulfide minerals are distinguished because these highly reactive minerals may have a disproportionately large effect on water chemistry. High calcium and bicarbonate (alkalinity) concentrations can result from the dissolution of relatively sparse carbonate minerals in rocks; high sulfate and metal concentrations can result from trace amounts or local concentrations of sulfide minerals exposed to oxidation and dissolution. The 29 units are further summarized into 6 major categories. Additional information on development of the classification scheme can be found in Robinson (1997). A detailed description of the classification scheme and associated expected water-quality and ecosystem characteristics follows. The water-quality and ecosystem characteristics presented below are intended primarily to describe characteristics relative to other rock units within the lithogeochemical classification scheme. These characteristics were determined from geochemical principles and previous studies (some cited above) on the relation of rock type and water-quality and ecosystem characteristics. Topographic characteristics described below are based on geologic and geochemical principles and regional physiographic trends; these characteristics are incorporated into the lithophysiographic domains described below. >LITHO_UNIT: 11 (not in the CONN NAWQA study area) >DESCRIPTION: limestone, dolomite, and carbonate-rich clastic > sediments >MAJOR CATEGORY: carbonate-rich rocks >CHEMICAL CHARACTER OF NATURAL WATERS: high alkalinity, calcium, > and bicarbonate concentrations; high pH; may have high concentrations > of sulfate and solutes complexed by bicarbonate ion, such as arsenic > and uranium >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: > low sensitivity to acid deposition; flora favoring alkaline, high- > calcium soils may occur; productive aquatic faunas >SOIL CHARACTERISTICS: generally thin alkaline clay soils; high > calcium, low potassium availability; may form iron-gossan in > weathered sulfide-rich facies >TOPOGRAPHIC EXPRESSION: generally lowlands and topographic > depressions; may be sites of stream and river channels, ponds, > lakes, and ground-water discharge > >LITHO_UNIT: 12 >DESCRIPTION: marble, including dolomitic marble; may include some > calc-silicate rock >MAJOR CATEGORY: same as 11 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 11 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 11 >SOIL CHARACTERISTICS: same as 11 >TOPOGRAPHIC EXPRESSION: same as 11 > >LITHO_UNIT: 12s >DESCRIPTION: sulfidic marble; may include some calc-silicate rock >MAJOR CATEGORY: same as 11 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 11 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 11 >SOIL CHARACTERISTICS: same as 11 >TOPOGRAPHIC EXPRESSION: same as 11 > >LITHO_UNIT: 13 >DESCRIPTION: calcareous clastic and metaclastic rocks containing > approximately 15 to 45 percent carbonate minerals >MAJOR CATEGORY: same as 11 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 11 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 11 >SOIL CHARACTERISTICS: same as 11 >TOPOGRAPHIC EXPRESSION: same as 11 > >LITHO_UNIT: 21 >DESCRIPTION: tan and red mudstone and shale; may include sandstone; > locally contains minor carbonate and(or) sulfate (gypsum) minerals >MAJOR CATEGORY: carbonate-poor, clastic sedimentary rocks restricted > to distinct depositional basins (bedded lithologies below biotite- > grade of regional metamorphism) >CHEMICAL CHARACTER OF NATURAL WATERS: generally high sodium > and sometimes high calcium and sulfate concentrations; ground > water may have moderate to high solute concentrations where acidic > or high sulfate concentrations exist; iron concentrations may be > high in ground water where Eh and pH are low; distinct ground-water > types may be localized within the area of the depositional basin >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: low > to moderate sensitivity to acid deposition >SOIL CHARACTERISTICS: clay soils; variably neutral to acidic >TOPOGRAPHIC EXPRESSION: variable; generally lowlands with subdued > topography in the study area > >LITHO_UNIT: 21cs >DESCRIPTION:description calcareous, locally sulfidic, gray mudstone > and shale >MAJOR CATEGORY: same as 21 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 21 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 21 >SOIL CHARACTERISTICS: same as 21 >TOPOGRAPHIC EXPRESSION: same as 21 > >LITHO_UNIT: 22 >DESCRIPTION: interbedded mudstone, shale, and siltstone; may contain > sandstone >MAJOR CATEGORY: same as 21 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 21 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 21 >SOIL CHARACTERISTICS: same as 21 >TOPOGRAPHIC EXPRESSION: same as 21 > >LITHO_UNIT: 23 >DESCRIPTION: sandstone and interbedded sandstone and conglomerate; > may contain siltstone, shale, and mudstone >MAJOR CATEGORY: same as 21 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 21 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 21 >SOIL CHARACTERISTICS: same as 21 >TOPOGRAPHIC EXPRESSION: same as 21 > >LITHO_UNIT: 31 >DESCRIPTION: slate and graywacke >MAJOR CATEGORY: metamorphosed clastic sedimentary rocks (primarily > non-calcareous; may include felsic and mafic metavolcanic rocks; > rocks may be foliated, recrystallized, highly deformed; highly > variable rock types may be exposed in individual drainage basins) >CHEMICAL CHARACTER OF NATURAL WATERS: low to moderate solute > concentrations; generally low calcium-to-sodium ratios; variable > potassium-to-sodium ratios; higher calcium concentrations when > slightly calcareous >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: > moderate to high sensitivity to acid deposition >SOIL CHARACTERISTICS: rocky soils >TOPOGRAPHIC EXPRESSION: uplands and ridges > >LITHO_UNIT: 31s >DESCRIPTION: graphitic and sulfidic slate and graywacke >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: low to moderate solute > concentrations; iron concentrations may be high in ground water > where Eh and pH are low; sulfate concentrations may be high >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: > moderately sensitive to acid deposition; endemic floras may occur > in acidic metal-rich soils over sulfide-rich horizons >SOIL CHARACTERISTICS: rocky acidic soils; acidic metal-rich soils > may occur >TOPOGRAPHIC EXPRESSION: same as 31 > >LITHO_UNIT: 32 >DESCRIPTION: pelitic schist and phyllite; may include granofels >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 31 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 31 >SOIL CHARACTERISTICS: clay soils >TOPOGRAPHIC EXPRESSION: moderate hills > >LITHO_UNIT: 32c >DESCRIPTION: pelitic schist and phyllite; may include granofels; > calcareous >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 31, but with higher > calcium concentrations likely >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 31 >SOIL CHARACTERISTICS: same as 32 >TOPOGRAPHIC EXPRESSION: same as 32 > >LITHO_UNIT: 32s >DESCRIPTION: sulfidic schist; may include sulfidic granofels >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 31s >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTIC: same > as 31s >SOIL CHARACTERISTICS: clay soils (same as 32); acidic metal-rich soils > may occur >TOPOGRAPHIC EXPRESSION: low to moderate hills > >LITHO_UNIT: 32cs >DESCRIPTION: pelitic schist and phyllite; may include granofels; > calcareous and sulfidic >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: similar to 32c and 32s >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: > similar to 32c and 32s >SOIL CHARACTERISTICS: similar to 32c and 32s >TOPOGRAPHIC EXPRESSION: similar to 32c and 32s > >LITHO_UNIT: 33 >DESCRIPTION: mixed schist, granofels, and gneiss >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 31 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 31 >SOIL CHARACTERISTICS: clay to sandy soils >TOPOGRAPHIC EXPRESSION: low to moderate rolling hills > >LITHO_UNIT: 33c >DESCRIPTION: mixed schist, granofels, and gneiss; slightly calcareous >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 31, but with higher > calcium concentrations likely >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 31 >SOIL CHARACTERISTICS: same as 33 >TOPOGRAPHIC EXPRESSION: same as 33 > >LITHO_UNIT: 33s >DESCRIPTION: sulfide-bearing schistose granofels and mixed > schist and gneiss (sulfidic character may be local) >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 31s >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 31s >SOIL CHARACTERISTICS: clay to sandy soils (same as 33); acidic metal- > rich soils may occur >TOPOGRAPHIC EXPRESSION: low hills > >LITHO_UNIT: 34 >DESCRIPTION: quartzose metasandstone, quartzite, quartz granofels, > and quartzose gneiss >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: generally low solute > concentrations; low pH; high potassium-to-sodium ratios >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTIC: same > as 31 >SOIL CHARACTERISTICS: sandy to rocky soils >TOPOGRAPHIC EXPRESSION: same as 31 > >LITHO_UNIT: 34c >DESCRIPTION: quartzose metasandstone, quartzite, quartz granofels, and > quartzose gneiss; locally includes schistose or calcareous units >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 34 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 31 >SOIL CHARACTERISTICS: same as 34 >TOPOGRAPHIC EXPRESSION: same as 31 > >LITHO_UNIT: 35 >DESCRIPTION: interlayered granitic gneiss, schist, mafic gneiss, and > amphibolite >MAJOR CATEGORY: same as 31 >CHEMICAL CHARACTER OF NATURAL WATERS: low to moderate solute > concentrations, variable calcium- and magnesium-to-sodium ratios >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: > variable sensitivity to acid deposition >SOIL CHARACTERISTICS: clay to sandy soils >TOPOGRAPHIC EXPRESSION: low to moderate rolling hills, uplands, and > highlands > >LITHO_UNIT: 41 >DESCRIPTION: basalt >MAJOR CATEGORY: mafic igneous rocks and their metamorphic equivalents >CHEMICAL CHARACTER OF NATURAL WATERS: high calcium- and magnesium-to- > sodium ratios; variable silica concentrations (sometimes high due to > dissolution of reactive silicates); where Eh and pH are low, iron > and manganese concentrations are high >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: low > sensitivity to acid deposition; may have endemic flora favoring > alkaline, high-magnesium and low-potassium soils; productive aquatic > faunas where calcium is high in surface waters >SOIL CHARACTERISTICS: thin, rocky, smectite clay > soils; high in magnesium, low in potassium >TOPOGRAPHIC EXPRESSION: moderate ridges and hills > >LITHO_UNIT: 42 >DESCRIPTION: amphibolite, greenstone, greenschist-facies metavolcanics, > and schistose mafic rock with minor dispersed carbonate >MAJOR CATEGORY: same as 41 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 41 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 41 >SOIL CHARACTERISTICS: same as 41 >TOPOGRAPHIC EXPRESSION: same as 41 > >LITHO_UNIT: 43 >DESCRIPTION: mafic gneiss and mafic lithologies mixed with felsic > volcanics and(or) metaclastic lithologies >MAJOR CATEGORY: same as 41 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 41 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 41 >SOIL CHARACTERISTICS: iron-rich smectite clay soils, with poor > drainage; neutral to basic; high magnesium >TOPOGRAPHIC EXPRESSION: moderate rolling topography > >LITHO_UNIT: 44 >DESCRIPTION: mafic plutonic rocks, including gabbro, diorite, > monzodiorite, and diabase >MAJOR CATEGORY: same as 41 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 41 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 41 >SOIL CHARACTERISTICS: same as 43 >TOPOGRAPHIC EXPRESSION: lowlands or uplands, depending upon adjacent > lithologies > >LITHO_UNIT: 50 >DESCRIPTION: ultramafic rocks, including serpentinites, dunites, > peridotites, and talc schists >MAJOR CATEGORY: ultramafic rocks >CHEMICAL CHARACTER OF NATURAL WATERS: high magnesium-to-calcium > ratios; relatively high silica concentrations due to dissolution > of reactive silicates; ground water may have low Eh values and high > metal concentrations >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: low > sensitivity to acid deposition; frequently has endemic flora > favoring high-magnesium, low-potassium, alkaline soils >SOIL CHARACTERISTICS: thin, rocky, iron-rich soils; high-magnesium, > low-potassium, alkaline soils may occur >TOPOGRAPHIC EXPRESSION: upland hills, knobs, or ridges > >LITHO_UNIT: 50c >DESCRIPTION: ultramafic rocks, including serpentinites, dunites, > peridotites, and talc schists; carbonate present >MAJOR CATEGORY: same as 50 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 50 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTISTICS: same > as 50 >SOIL CHARACTERISTICS: same as 50 >TOPOGRAPHIC EXPRESSION: same as 50 > >LITHO_UNIT: 61 >DESCRIPTION: granitoid plutonic rocks, including granite, > quartz monzonite, granodiorite, tonalite, trondhjemite, and > equivalent gneiss >MAJOR CATEGORY: felsic igneous and plutonic rocks and > their metamorphic equivalents >CHEMICAL CHARACTER OF NATURAL WATERS: generally low solute > concentrations; relatively high sodium, bicarbonate, and silica > concentrations; calcium and magnesium concentrations generally are > low; relatively low pH; fluoride, uranium, and radon concentrations > may be high; >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: high > sensitivity to acid deposition >SOIL CHARACTERISTICS: generally sandy soils >TOPOGRAPHIC EXPRESSION: uplands and highlands; uplands may have little > internal relief and steep slopes along borders > >LITHO_UNIT: 61v >DESCRIPTION: fine-grained felsic rocks of volcanic and subvolcanic > origin; includes feldspathic hypabyssal dikes and flows >MAJOR CATEGORY: same as 61 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 61 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 61 >SOIL CHARACTERISTICS: same as 61 >TOPOGRAPHIC EXPRESSION: same as 61 > >LITHO_UNIT: 62 >DESCRIPTION: quartz-poor plutonic rocks, including syenite, nepheline > syenite, quartz syenite, monzonite, and anorthosite >MAJOR CATEGORY: same as 61 >CHEMICAL CHARACTER OF NATURAL WATERS: same as 61 >SENSITIVITY TO ACID DEPOSITION AND OTHER HABITAT CHARACTERISTICS: same > as 61 >SOIL CHARACTERISTICS: thin clay soils >TOPOGRAPHIC EXPRESSION: same as 61 > > (B) DESCRIPTION OF THE LITHOPHYSIOGRAPHIC DOMAINS: The lithogeochemical rock units in the study area have been grouped into nine regional lithologic and physiographic provinces (lithophysiographic domains) that are defined using lithogeochemical contacts but are similar to the physiographic provinces of Denny (1982); the lithophysiographic domains are further summarized into (1) the western highlands and lowlands, (2) central lowlands, and (3) eastern highlands. Physiographic provinces are areas of similar topography that are topographically distinct from adjacent areas. As Hunt (1974, p. 3) states, "Each province has characteristics peculiar to itself--a distinctive structural framework giving rise to distinctive landforms expressing their structure and, for the most part, distinctive climate, vegetation, soils, water and other resources." In early physiographic mapping, the study area covered by this data layer was considered mostly upland. However geologic mapping by Federal, State, and academic geologists during the last 40 years has resulted in a more detailed understanding of bedrock structure, stratigraphy, and tectonic evolution than was available for earlier physiographic schemes. Thus, the nine domains defined in this data layer are smaller than previously defined physiographic provinces and are based on tectonic and lithogeochemical characteristics as well as physiography. The generalized topographic expression and lithology in the lithophysiographic domains, arranged from west to east across the study area, are as follows. >LITHOPHYSIOGRAPHIC DOMAIN: Taconic allochthons and related rocks of > early Paleozoic age (T) >MAJOR CATEGORY: western highlands and lowlands >TOPOGRAPHIC EXPRESSION: mostly uplands in west; moderate hills and > ridges in Vermont >LITHOLOGY: mostly schist (32) and slate, phyllite and graywacke (31); > some sulfidic units > >LITHOPHYSIOGRAPHIC DOMAIN: Carbonate platform sequence of early > Paleozoic age (S) >MAJOR CATEGORY: western highlands and lowlands >TOPOGRAPHIC EXPRESSION: lowlands and valleys >LITHOLOGY: mostly marble (12) and bedded limestone and dolomite (11; > not mapped separately in study-area source materials) > >LITHOPHYSIOGRAPHIC DOMAIN: Proterozoic crystalline massifs and > associated early Paleozoic sediments (Y) >MAJOR CATEGORY: western highlands and lowlands >TOPOGRAPHIC EXPRESSION: highland plateaus with subdued relief; may > have steep slopes along border >LITHOLOGY: mostly granitic gneiss (61) and mafic gneiss (43), with > schist and granofels (33) and minor marble (12); mixed granitic > gneiss, mafic gneiss, and schist (35) in Vermont; minor quartzose > metaclastics (34) > >LITHOPHYSIOGRAPHIC DOMAIN: Hartland-Rowe-Hawley Metamorphic Belt (H) >MAJOR CATEGORY: central lowlands >TOPOGRAPHIC EXPRESSION: rolling terrain with moderate hills >LITHOLOGY: mostly granofels and schist (32, 33, 34), with amphibolite > (42), mafic gneiss (43), and granitic gneiss (61); some sulfidic > units; locally abundant small, isolated bodies of ultramafic rock > (50) > >LITHOPHYSIOGRAPHIC DOMAIN: Newark Supergroup of early Mesozoic age (N) >MAJOR CATEGORY: central lowlands >TOPOGRAPHIC EXPRESSION: lowlands, except in areas of basalt flows and > diabase bodies; forms wide valley in Massachusetts and Connecticut >LITHOLOGY: mostly mudstone (21) and sandstone (22, 23) clastic bodies > filling fault-bounded grabens; local basalt flows (41), basalt dikes > (41), and diabase bodies (44); some calcareous units, local sulfidic > horizons, and sediments containing sulfate minerals > >LITHOPHYSIOGRAPHIC DOMAIN: Connecticut River Valley Metamorphic > Belt (C) >MAJOR CATEGORY: central lowlands >TOPOGRAPHIC EXPRESSION: subdued rolling terrain; rounded granitic > plutons form high ground in northeastern Vermont >LITHOLOGY: mostly metamorphosed calcareous clastic sediments > (13) and granofels and schist (33) in Vermont; less calcareous (33c) > in New Hampshire; granite plutons (61) in northeastern Vermont > >LITHOPHYSIOGRAPHIC DOMAIN: Bronson Hill Metamorphic Belt (B) >MAJOR CATEGORY: eastern highlands >TOPOGRAPHIC EXPRESSION: mostly uplands with rolling terrain; local > steep slopes and ridges >LITHOLOGY: mostly granitic gneiss (61), mafic gneiss (43), and > amphibolite (42), with schist, sulfidic schist, and granofels (32, > 32s, 33, 33s, 34) > >LITHOPHYSIOGRAPHIC DOMAIN: Merrimack Metamorphic Belt (M) >MAJOR CATEGORY: eastern highlands >TOPOGRAPHIC EXPRESSION: rolling terrain with moderate hills and ridges; > granites form mountainous highland in New Hampshire. >LITHOLOGY: mostly a variety of metamorphosed clastic rocks (32, 33, > and 34) and granitic plutons (61); local areas of mafic gneiss (43) > and amphibolite (42); some sulfidic and(or) calcareous units > >LITHOPHYSIOGRAPHIC DOMAIN: Coastal Gneiss Belt (Z) >MAJOR CATEGORY: eastern highlands >TOPOGRAPHIC EXPRESSION: subdued terrain with gentle slopes along the > coast of Connecticut and low to moderate hills and ridges inland >LITHOLOGY: mostly granitic gneiss (61) and mafic gneiss (43) > > (C) REFERENCES CITED IN THIS SECTION Amiotte-Suchet, P. and Probst, J.L., 1993, Flux du CO2 consomme' par alteration chemique continentale: influences du drainage et de la lithologie: CR Academie Sciences, Paris, v. 317, no. II, p. 615-622. Bowen, N.L., 1922, The reaction principle in petrogenesis: Journal of Geology, v. 30, p. 177-198. Bricker, O.P. and Rice, K.C., 1989, Acidic deposition to streams: Environmental Science and Technology, v. 23, p. 379-385. Clarke, F.W., 1924, The composition of river and lake waters of the United States: U.S. Geological Survey Professional Paper 135, 199 p. Denny, C.S., 1982, Geomorphology of New England: U.S. Geological Survey Professional Paper 1208, 18 p. Garrels, R.M., 1967, Genesis of some ground waters from igneous rocks, in Ableson, P., ed., Researches in Geochemistry, v. 2: Wiley, New York, p. 405-420. Garrels, R.M. and MacKenzie, F.T., 1967, Origin of the chemical composition of some springs and lakes, in Equilibrium Concepts in Natural Water Systems: American Chemical Society, Cleveland, Ohio, p. 222-242. Glass, N.R., Arnold, D.E., Galloway, J.N., and others, 1982, Effect of acid precipitation: Environmental Science and Technology, v. 16, no. 3, p. 162a-169a. Goldich, S.S., 1938, A study in rock weathering: Journal of Geology, v. 46, p.17-58. Hem, J.D., 1989, Study and interpretation of the chemical characteristics of natural water: U.S. Geological Survey Water-Supply Paper 2254, 264 p. Hunt, C.B., 1974, Natural Regions of the United States and Canada: W.H. Freeman and Company, San Francisco, Calif., 725 p. Jackson, M.L., Tyler, S.A., Willis, A.L., and others, 1948, Weathering sequence of clay-size minerals in soils and sediments: Journal of Physical Chemistry, v. 52, p. 1237-1260. Peper, J.D., Grosz, A.E., Kress, T.H., Collins, T.B., Kappesser, G.B., Huber, C.M., and Webb, J.R., 1995, Acid deposition sensitivity map of the Southern Appalachian Assessment Area, Virginia, North Carolina, Tennessee, South Carolina, Georgia, and Alabama: U.S. Geological Survey On-Line Digital Data Series Open-File Report 95-810, scale 1:1,000,000. Robinson, G.R., Jr., 1997, Portraying chemical properties of bedrock for water quality and ecosystem analysis: an approach for New England: U.S. Geological Survey Open-File Report 97-154, 11 p. Rose, A.W., Hawkes, H.E., and Webb, J.S., 1979, Geochemistry in Mineral Exploration, 2nd ed.: Academic Press, New York, 657 p. Vebel, M.A., 1985, Geochemical mass balances and weathering rates in forested watersheds of the southern Blue Ridge: American Journal of Science, v. 285, p. 904-930. Webb, J.R., Deviney, F.A., and Galloway, J.N., 1994, The acid-base status of native brook trout streams in the mountains of Virginia: Report to the Virginia Department of Game and Inland Fisheries, 91 p. White, A.F., 1995, Chemical weathering rates of silicate minerals in soils, in White, A.F. and Brantley, S.L., eds., Chemical weathering rates of silicate minerals: Reviews in Mineralogy, v. 31, Mineralogical Society of America, Washington, D.C., Chapter 9, p. 407-461. White, D.E., Hem, J.D., and Waring, G.A., 1963, Chemical composition of sub- surface waters: U.S. Geological Survey Professional Paper 440-F, 67 p. Appendix--Geologic map code from source materials (column 1), lithogeochemical code (column 2) lithophysiographic domain (column 3; see description of litho- physiographic domains, above, for definitions of letter codes), State (column 4) and formation name (column 5; Fm, formation; Mbr or mbr, member; Mtn, Mountain) as depicted in the data layer. Geologic and formation names listed below are the geologic names used on the cited base maps. These geologic base maps have not been reviewed for conformity with the North American Stratigraphic Code, with current usage, or with current Geological Survey editorial standards. Where appropriate, alternative geologic names are provided in parantheses that conform to preferred current usage by the U.S. Geological Survey. Current status of geologic name usage may be obtained from the Internet at http://ngmdb.usgs.gov/Geolex/geolex_home.html. >Jd 41 N MA diabase dikes and sills >Jp 21 N MA Portland Fm (western part) >Jp 22 N MA Portland Fm (eastern part) >Jpc 22 N MA Portland Fm >Jpc 23 N MA Portland Fm >Je 22 N MA East Berlin Fm >Jec 23 N MA East Berlin Fm >Jsm 22 N MA Shuttle Meadow Fm >Jsmc 23 N MA Shuttle Meadow Fm >Jn/Trn 22 N MA New Haven Arkose (eastern part) >Jgb 41 N MA Granby Basaltic Tuff >Jhab 41 N MA Hampden Basalt >Jhb 41 N MA Holyoke Basalt >Jhv 41 N MA Hitchcock Volcanics >Jm 22 N MA Mount Toby Fm >Jmc 23 N MA Mount Toby Fm >Jma 23 N MA Mount Toby Fm >Jt 22 N MA Turner Falls Sandstone >Jtc 23 N MA Turner Falls Sandstone >Jdb 41 N MA Deerfield Basalt >Js 22 N MA Sugarloaf Fm >Jsc 23 N MA Sugarloaf Fm >Trs 23 N MA Sugarloaf Fm >Dwgd 61 B MA Williamsburg Granodiorite >Dpe 61 C MA feldspar-quartz-muscovite pegmatite >Dgr 61 B MA biotite-muscovite granite >Dmg 61 H MA Middlefield Granite >grg 61 B MA biotite granitic gneiss >Dbmd 44 B MA Belchertown Complex >Dbmdt 44 B MA Belchertown Complex >Dbmdg 44 B MA Belchertown Complex >Dbh 44 B MA Belchertown Complex >Dbi 44 B MA Belchertown Complex >Dbt 44 B MA Belchertown complex >Dbd 44 B MA Belchertown Complex >Dpgg 61 C MA Prescott Complex, Cooleyville Granitic > Gneiss >Dpgb 44 B MA Prescott Complex >Dpv 33 C MA Putney Volcanics >Dgm 33c C MA Gile Mtn Fm >Dgmq 33c C MA Gile Mtn Fm >Dgma 42 C MA Gile Mtn Fm >Dw 13 C MA Waits River Fm >Dwt 13 C MA Waits River Fm >Dwa 42 C MA Waits River Fm >Dgu 33c H MA Goshen Fm >Dgq 34 H MA Goshen Fm >Dg 32 H MA Goshen Fm >Dgp 32 H MA Goshen Fm >Dgl 33c H MA Goshen Fm >Dgc 13 H MA Goshen Fm >De 33 B MA Erving Fm >Dev 33 B MA Erving Fm >Deg 33 B Ma Erving Fm >Dea 42 B MA Erving Fm >Dl 32 B MA Littleton Fm >Sr 34c B MA Russell Mtn Fm >Sf 34c B MA Fitch Fm >Sc 34c B MA Clough Quartzite >Dl 32 M MA Littleton Fm >Sr 34c M MA Russell Mtn Fm >Sf 34c M MA Fitch Fm >Sc 34c M MA Clough Quartzite >Dgd 61 M MA granodiorite >gd 61 M MA granodiorite >qd 44 M MA quartz diorite >gr 61 M MA granite >Dgr 61 M MA biotite-muscovite granite >hg 43 M MA hornblende-plagioclase gneiss >grg 61 M MA biotite granitic gneiss >gb 44 M MA hornblende-olivine gabbro >Dht 44 M MA Hardwick Tonalite >Dhgr 44 M MA Hardwick Tonalite >Drh 61 M MA Hardwick Tonalite, Ragged Hill >Ddi 44 M MA Hardwick Tonalite, biotite-hornblende > diorite and quartz-bearing diorite >Ddn 44 M MA Hardwick Tonalite, meladiorite and tonalite >Dchgr 61 M MA Coys Hill Porphyritic Granite Gneiss >Dchh 43 M MA Coys Hill Porphyritic Granite Gneiss >Dlo 34 M MA Littleton Fm >Dlf 34 M MA Littleton Fm >Dlm 12 M MA Littleton Fm >Dl+Ops 32s M MA Littleton and Partridge Fms, interfolded >Sfs 33s M MA Fitch Fm >Sfss 33s M MA Fitch Fm >Sp 33s M MA Paxton Fm >Spss 32s M MA Paxton Fm >Spa 42 M MA Paxton Fm >Spsq 33s M MA Paxton Fm >Spqr 33s M MA Paxton Fm >Spbs 33s M MA Paxton Fm, Bigelow Brook Mbr >Spso 33c M MA Paxton Fm, Southbridge Mbr >Spbc 33c M MA Paxton Fm >So 33c M MA Oakdale Fm >Sagr 61 M MA Ayer Granite >Ogd 44 T MA diorite at Goff Ledges >Od 44 H MA diorite >Otr 61 Y MA alaskite and trondhjemite >Ogr 61 Y MA muscovite-biotite granite and granodiorite >Ogr 61 T MA muscovite-biotite granite and granodiorite >OZu 50 Y MA serpentinized peridotite stocks >Zd 43 y MA biotite-hornblende mafic dikes >Ytg 61 Y MA Tyringham Gneiss >Ysg 61 Y MA Stamford Granite Gneiss (Stamford Granite) >Ygg 61 Y MA granitoid gneiss >Ow 32c S MA Walloomsac Fm >Owq 34c S MA Walloomsac Fm >Owm 12s S MA Walloomsac Fm >Owl 12 S MA Walloomsac Fm >Osg 12 S MA Stockbridge Fm >Osf 12 S MA Stockbridge Fm >Ose 12 S MA Stockbridge Fm >Osd 12 S MA Stockbridge Fm >Csc 12 S MA Stockbridge Fm >Csb 12 S MA Stockbridge Fm >Csa 12 S MA Stockbridge Fm >Cc 34 Y MA Cheshire Quartzite >CZd 34 Y MA Dalton Fm >CZdbs 34 Y MA Dalton Fm >CZdq 34 Y MA Dalton Fm >CZdg 34 Y MA Dalton Fm >CZds 34 Y MA Dalton Fm >CZdc 34 Y MA Dalton Fm >CZhd 32 Y MA Hoosac Fm >CZhgt 32 Y MA Hoosac Fm >CZhda 33 Y MA Hoosac Fm >CZhdc 33 Y MA Hoosac Fm >CZhg 32 T MA Hoosac Fm >CZhr 32 T MA Hoosac Fm >CZhgt 32 T MA Hoosac Fm >CZhk 33 T MA Hoosac Fm >CZh 32 T MA Hoosac Fm >CZh 32 Y MA Hoosac Fm >CZhw 32 T MA Hoosac Fm >CZhga 33 T MA Hoosac Fm >CZha 42 T MA Hoosac Fm >CZcm 32 T MA Canaan Mtn Fm >CZn 31 T MA Nassau Fm >CZngy 31 T MA Nassau Fm >CZna 31 T MA Nassau Fm >CZnp 31 T MA Nassau Fm >CZnr 31 T MA Nassau Fm >CZnv 42 T MA Nassau Fm >CZev 32 T MA Everett Fm >CZevc 31 T MA Everett Fm >Yb 43 Y MA biotite-plagioclase-quartz gneiss >Ybu 43 Y MA biotite-plagioclase-quartz gneiss >Ycs 12 Y MA calc-silicate granofels and gneiss >Yl 43 Y MA Lee Gneiss >Yhb 43 Y MA hornblende-biotite gneiss >Yfg 61 Y MA felsic biotite-microcline-plagioclase- > quartz gneiss >Yag 43 Y MA hornblende-biotite-plagioclase gneiss > and amphibolite >Ya 42 Y MA amphibolite >Yw 33s Y MA Washington Gneiss >Ywb 33s Y MA Washington Gneiss >Ywhg 43 Y MA Washington Gneiss >Ywcs 12s Y MA Washington Gneiss >Ysm 12s Y MA Sherman Marble >Ohpg 61 H MA gneiss at Hallockville Pond >u 50 H MA serpentinite and(or) talc rock >Oh 43 H MA Hawley Fm >Ohb 32cs H MA Hawley Fm >Ohg 43 H MA Hawley Fm >Ohp 43 H MA Hawley Fm >Ohf 43 H MA Hawley Fm >Ocd 32 H MA Cobble Mtn Fm >Occ 32 H MA Cobble Mtn Fm >Occr 32(s) H MA Cobble Mtn Fm >Occa 32 H MA Cobble Mtn Fm >Ocu 50 H MA Cobble Mtn Fm >Ocb 33 H MA Cobble Mtn Fm >Ocbr 33s H MA Cobble Mtn Fm >Oca 33c H MA Cobble Mtn Fm >Ocar 33 H MA Cobble Mtn Fm >Om 33 H MA Moretown Fm >Oms 33 H MA Moretown Fm >Omsc 33 H MA Moretown Fm >Oml 33 H MA Moretown Fm >Omsk 33 H MA Moretown Fm >Oma 42 H MA Moretown Fm >OCr 33 H MA Rowe Schist >OCrc 33 H MA Rowe Schist >OCra 42 H MA Rowe Schist >Ogl 61 B MA Glastonbury Gneiss >Opc 61 B MA Pauchaug Gneiss >Ops 32s B MA Partridge Fm >Opsa 32cs B MA Partridge Fm >Opsc 32cs B MA Partridge Fm >Opa 42 B MA Partridge Fm >Opv 43 B MA Partridge Fm >Opvs 43 B MA Partridge Fm >Opau 44 B MA Partridge Fm >Opu 50 B MA Partridge Fm >Opsg 33 B MA Partridge Fm >Opf 34 B MA Partridge Fm >Ops 32s M MA Partridge Fm >Opsa 32cs M MA Partridge Fm >Opsc 32cs M MA Partridge Fm >Opa 42 M MA Partridge Fm >Opv 43 M MA Partridge Fm >Opvs 43 M MA Partridge Fm >Opau 44 M MA Partridge Fm >Opu 50 M MA Partridge Fm >Opsg 33 M MA Partridge Fm >Opf 34 M MA Partridge Fm >Opbg 34 B MA Partridge Fm >Dl+Ops 32s M MA Littleton Fm and Partridge Fm, interfolded >Oa 43 B MA Ammonoosuc Volcanics >Oau 50 B MA Ammonoosuc Volcanics >Oaq 34 B MA Ammonoosuc Volcanics >Ococ 32 H MA Collinsville Fm >Ocoa 43 H MA Collinsville Fm >Ocoa1 43 H MA Collinsville Fm >Ocof 43 H MA Collinsville Fm >Oco 43 H MA Collinsville Fm >Ocoa2 43 H MA Collinsville Fm >Ocog 34 H MA Collinsville Fm >Ocor 43 H MA Collinsville Fm >Ocoa3 43 H MA Collinsville Fm >Ozmo 43 B MA Monson Gneiss >OZmou 50 B MA Monson Gneiss >OZmoa 42 B MA Monson Gneiss >OZfm 43 B MA Fourmile Gneiss >OZfmu 50 B MA Fourmile Gneiss >OZfmq 34 B MA Fourmile Gneiss >Zpm 61 B MA Poplar Mtn Gneiss >Zpmg 61 B MA Poplar Mtn Gneiss >Zpmq 61 B MA Poplar Mtn Gneiss >Zmm 32 B MA Mount Mineral Fm >Zmmu 50 B MA Mount Mineral Fm >Zdh 61 B MA Dry Hill Gneiss >Zdhs 33 B MA Dry Hill Gneiss >Zdpq 61 B MA Dry Hill Gneiss >Zpd 61 B MA Poplar Mtn and Dry Hill Gneisses, > undifferentiated >OZt 33s M MA Tatnic Hill Fm >OZty 32 M MA Tatnic Hill Fm, Yantic Mbr >OZtf 33c M MA Tatnic Hill Fm, Fly Pond Mbr >OZn 33s M MA Nashoba Fm >OZnb 42 M MA Nashoba Fm, Boxford Mbr >OZf 34 M MA Fish Brook Gneiss >OZsh 34cs M MA Shawsheen Gneiss >OZq 43 M MA Quinebaug Fm >Zp 34 Z MA Plainfield Fm >Zhg 61 Z MA Hope Valley Alaskite Gneiss >Zsg 61 Z MA Scituate Granite Gneiss (Scituate Granite) >Zw 43 Z CT Waterford Group >Zwr 43 Z CT Waterford Group, Rope Ferry Gneiss >Zwn 43 Z CT Waterford Group, New London Gneiss >Zwnj 61 Z CT Waterford Group, New London Gneiss >Zwm 43 Z CT Waterford Group, Mamacoke Fm >Zp 34 Z CT Plainfield Fm >Zpq 34 Z CT Plainfield Fm >Zsh 61 Z CT Sterling Plutonic Suite (Group), Hope > Valley Alaskite >Zsph 61 Z CT Sterling Plutonic Suite (Group), Potter > Hill Granite >Zspp 61 Z CT Sterling Plutonic Suite (Group), Potter > Hill Granite >Zss 61 Z CT Sterling Plutonic Suite (Group), > "Scituate" Granite Gneiss >Zsp 61 Z CT Sterling Plutonic Suite (Group), > Ponaganset Gneiss >Zl 61 Z CT Sterling Plutonic Suite (Group), Light > House Gneiss >Zb 61 Z CT Sterling Plutonic Suite (Group), > Branford Gneiss >Pw 61 Z CT Westerly Granite >Pn 61 Z CT Narragansett Pier Granite >Pnm 61 Z CT Narragansett Pier Granite >Dm 61 B CT Maromas Granite Gneiss >Ogl 61 B CT Glastonbury Gneiss >u 50 B CT ultramafic rock >Omm 43 B CT Middletown Fm >De 33 B CT Erving Fm >De 33 C CT Erving Fm >Dbl 32 B CT Littleton Fm >Dblm 33 B CT Littleton Fm, Mount Pisgah Mbr >Sbf 34c B CT Fitch Fm >Sbc 34 B CT Clough Quartzite >Och 32s B CT Collins Hill Fm >Ochv 43 B CT Collins Hill Fm >Om 43 B CT Middletown Fm >Omu 43 B CT Middletown Fm >Oml 43 B CT Middletown Fm >Omm 43 B CT Middletown Fm >Omo 43 B CT Monson Gneiss >DSs 32 M CT Oakdale Fm, Scotland Schist Mbr >DSsq 34 M CT Oakdale Fm, Scotland Schist Mbr >SObu 33s M CT Bigelow Brook Fm >SObu 32 M CT Bigelow Brook Fm >SObm 33c M CT Bigelow Brook Fm >SObl 33s M CT Bigelow Brook Fm >SOs 33s M CT Southbridge Fm >SOsp 61 M CT Southbridge Fm >SOh 33s M CT Hebron Gneiss (Hebron Fm) >Obr 32s M CT Brimfield Schist >Obrg 43 M CT Brimfield Schist >Obrg 32s M CT Brimfield Schist >Ota 33s M CT Tatnic Hill Fm, >Otay 33s M CT Tatnic Hill Fm, Yantic Mbr >Otaf 33c M CT Tatnic Hill Fm, Fly Pond Mbr >Oq 43 M CT Quinebaug Fm >Oqf 61 M CT Quinebaug Fm >Oqb 43 M CT Quinebaug Fm, Black Hill Mbr >Dgg 61 M CT granite gneiss >Dc 61 M CT Canterbury Gneiss >Dce 61 M CT Canterbury Gneiss, "Eastford gneiss phase" >D?d 43 M CT quartz diorite >Dn 44 M CT hornblende norite >Dl 44 M CT Lebanon Gabbro (Lebanon Granite) >Dld 44 M CT Lebanon Gabbro (Lebanon Granite) >Op 44 M CT Preston Gabbro >Opd 44 M CT Preston Gabbro >Pp 61 H CT porphyry >Ppa 61 H CT Pinewood Adamallite >Ps 62 H CT syenite >Dng 61 H CT Nonewaug Granite >Og 61 H CT granitic gneiss >Ol 44 H CT Litchfield Norite >Ob 43 H CT Brookfield Gneiss >u 50 H CT ultramafic rock >DSt 32 H CT Straits Schist >DSts 33 H CT Straits Schist, Southington Mtn Mbr >Stb 33s H CT Straits Schist >Otf 33 H CT Trap Falls Fm >Otfc 33s H CT Trap Falls Fm, Carringtons Pond Mbr >Otfs 33 H CT Trap Falls Fm, Shelton Mbr >Otfg 33 H CT Trap Falls Fm >Ocm 33 H CT Cobble Mtn Fm >Ohc 32cs H CT Hawley Fm >Oh 43 H CT Harrison Gneiss >Ohp 43 H CT Harrison Gneiss, Pumpkin Ground Mbr >Ohb 43 H CT Harrison Gneiss, Beardsley Mbr >Ohn 43 H CT Harrison Gneiss >Ogh 33 H CT Golden Hill Schist >Or 33c H CT Ratlum Mtn Schist >Ora 42 H CT Ratlum Mtn Schist >OCr 33c H CT Rowe Schist >OCra 42 H CT Rowe Schist >Oc 33 H CT Collinsville Fm >Ocs 33 H CT Collinsville Fm, Sweetheart Mtn Mbr >Ocg 43 H CT Collinsville Fm >Ot+Oc 33 H CT Taine Mtn and Collinsville Fms, > undifferentiated >Oc+Ora 33c H CT Collinsville Fm and Ratlum Mtn Schist, > undifferentiated >Obs 34 H CT Bristol Gneiss >Ot 33 H CT Taine Mtn Fm >Otwv 33 H CT Taine Mtn Fm, Whigville Mbr >Ots 32 H CT Taine Mtn Fm, Scranton Mtn Mbr >Otw 33 H CT Taine Mtn Fm, Wildcat Mbr >Otb 33 H CT Taine Mtn Fm >Cwb 61 H CT Waterbury Gneiss >DSw 32 H CT Wepawaug Schist >Oma 42 H CT Maltby Lakes Metavolcanics >Omau 42 H CT Maltby Lakes Metavolcanics >Omal 42 H CT Maltby Lakes Metavolcanics >Oa 42 H CT Allingtown Metavolcanics >Oo 33 H CT Oronoque Schist >Ce 32 T CT Everett Schist >Cm 32 T CT Manhattan Schist >Cmcu 32s T CT Manhattan Schist, Canaan Mtn Schist >Cmcub 33s T CT Manhattan Schist, Canaan Mtn Schist >Cmcl 32s T CT Manhattan Schist, Canaan Mtn Schist >Cma 42 T CT Manhattan Schist >Ch 32 Y CT Hoosac Schist >Ch 32 T CT Hoosac Schist >Ow 32c S CT Walloomsac Schist >Owm 12s S CT Walloomsac Schist >OCs 12 S CT Stockbridge Marble >Osg 12 S CT Stockbridge Marble >Ose 12 S CT Stockbridge Marble >Csc 12 S CT Stockbridge Marble >Csb 12 S CT Stockbridge Marble >Csa 12 S CT Stockbridge Marble >Cc 34 Y CT Cheshire Quartzite >Cd 34 Y CT Dalton Fm >Cd 34 Y CT Dalton Fm >Yg 61 Y CT granitic gneiss, gneiss, and schist >Ygr 61 Y CT granitic gneiss >Yga 61 Y CT augen gneiss >Ygn 43 Y CT gneiss >Ygh 43 Y CT hornblende gneiss and amphibolite >Ygs 33s Y CT mica schist and gneiss >Jp 21 N CT Portland Arkose (western part) >Jp 22 N CT Portland Arkose (eastern part) >Jpc 23 N CT Portland Arkose >Je 22 N CT East Berlin Fm >Jsm 22 N CT Shuttle Meadow Fm >Trnh 23 N CT New Haven Arkose (western part) >Trnh 22 N CT New Haven Arkose (eastern part) >Jha 41 N CT Hampden Basalt >Jho 41 N CT Holyoke Basalt >Jta 41 N CT Talcott Basalt >Jb 44 N CT Buttress Dolerite >Jwr 44 N CT West Rock Dolerite >Jd 41 N CT diabase dikes >Dw 13 C VT Waits River Fm >Dws 42 C VT Waits River Fm, Standing Pond Volcanic Mbr >Dwc 34 C VT Waits River Fm, Crow Hill Mbr >Dg 33c C VT Gile Mtn Fm >Dgh 33 C VT Gile Mtn Fm, Hall Stream Mbr >Dga 42 C VT Gile Mtn Fm, amphibolite mbr >Dgm 31 C VT Gile Mtn Fm, Meetinghouse Slate Mbr >Dl 31,32 B VT Littleton Fm >DSn 31 H VT Northfield Fm >Sf 13 B VT Fitch Fm >Ss 13 H VT Shaw Mtn Fm (north of 44 degrees latitude) >Ss 34c H VT Shaw Mtn Fm (south of 44 degrees latitude) >Sc 34 B VT Clough Fm >Op 32s B VT Partridge Fm >Op 31s B VT Partridge Fm >Oa 42,61v B VT Ammonoosuc Volcanics >Oal 33 B VT Albee Fm >Oof 32 B VT Orfordville Fm >Oop 42 B VT Orfordville Fm, Post Volcanic Pond Mbr >Omcr 31 H VT Missisquoi Fm, Cram Hill Mbr >Omcr 31s H VT Missisquoi Fm, Cram Hill Mbr >Omc 32s H VT Missisquoi Fm, carbonaceous slate mbr > (southern part) >Omb 43 H VT Missisquoi Fm, Barnard Volcanic Mbr >Omw 33s H VT Missisquoi Fm, Whetstone Hill Mbr >Omm 33 H VT Missisquoi Fm, Moretown Mbr >OCs 32 H VT Stowe Fm >OCsg 42 H VT Stowe Fm, greenstone and amphibolite mbr >Co 32s H VT Ottauquechee Fm >Cog 42 H VT Ottauquechee Fm, greenstone and > amphibolite mbr >OCu 33s T VT Pinney Hollow, Ottauquechee Fm, and Stowe > Fms, undifferentiated >Cu 32 T VT Underhill Fm >Cub 33c T VT Underhill Fm, Battell Mbr >Cph 32 H,T VT Pinney Hollow Fm >Cpgc 42 H VT Pinney Hollow Fm, Chester Amphibolite Mbr >Cpg 42 H VT Pinney Hollow Fm, greenstone mbr >Cpc 32s H VT Pinney Hollow Fm, carbonaceous phyllite mbr >Ch 33 T VT Hazens Notch Fm >Cho 32 T VT Hoosac Fm >Chop 33 T VT Hoosac Fm, Plymouth Mbr >Cht 42 T VT Hoosac Fm, Turkey Mtn Mbr >Chog 42 T VT Hoosac Fm, amphibolite mbr >Ct 33c Y VT Tyson Fm >Cdt 33s Y VT Dalton Fm >Ccr 32 Y VT Cavendish Fm, Readsboro Mbr >Ccg 35 Y VT Cavendish Fm, Bull Hill Gneiss >Ccm 12 Y VT Cavendish Fm, dolomite marble mbr >pC 35 Y VT Mount Holly Complex >pCg 61 Y VT undifferentiated gneissic biotite granite, > quartz monzonite, and granodiorite >pCsq 34 Y VT Mount Holly Complex, quartzite mbr >pCm 12 Y VT Mount Holly Complex, calcite and dolomite > marble mbr >wg 61 C VT biotite and hornblende granites >ws 62 C VT hornblende, biotite, quartz, and augite > syenites >wd 44 C VT hornblende-biotite diorite; gabbro >wv 61v C VT volcanic breccia, felsitic tuff, and flows >nhc 44 C VT hornblende gabbro >nhu 61 C VT undifferentiated granitic rocks >hu 61 C VT undifferentiated granitic rocks >udp 50 H VT dunite, peridotite, and serpentinite >us 50c H VT serpentinite, carbonate rock, talc- > carbonate rock, and steatite >Jc1b 61 B NH Conway granite >J1b 61v B NH intrusive rhyolite >J1(x) 61 B NH granite porphyry >J1(a) 61v B NH intrusive rhyolite >J4(x) 62 B NH quartz syenite >J5 44 B NH hornblende-biotite quartz monzodiorite >J7(x) 62 B NH syenite >J7h 62 B NH hornblende syenite >J9A 44 M NH diorite >J9B 44 M NH gabbro >Jmv 61v M NH Moat Volcanics >P1m 61 M NH biotite granite >D1(a) 61 M NH twdo-mica granite >D1b 61 M NH biotite granite >D1m 61 M NH two-mica granite >D2-3b 61 M NH biotite-muscovite granodiorite >D2-5 61 M NH biotite-hornblende granodiorite to quartz > monzodiorite >D3A 61 B NH biotite tonalite >Dc1m 61 B NH Concord Granite >Ds1-6 61 M NH Spaulding Quartz Diorite Intrusive Suite > (Spaulding Tonalite) >Ds6-9B 44 M NH hypersthene-biotite quartz diorite and > gabbro >Db2-3 61 B NH biotite-muscovite granodiorite, tonalite, > and granite >Dk1-3(x)61 M NH Kinsman Quartz Monzonite Intrusive Suite > (Kinsman Intrusive Suite) >Dk1-4(x)61 M NH granite >DS9 44 B NH metamorphosed gabbro, diorite, and basalt > intrusives >DOu 50 B NH serpentinite >Dl 31,32 B NH Littleton Fm >Dlu 31 B NH Littleton Fm >Dll 32 B NH Littleton Fm >Dllc 33c B NH Littleton Fm >Dlv 43 B NH Littleton Fm >Dlvb 42 B NH Littleton Fm >Dlg 32s B NH Littleton Fm >Sf 13 B NH Fitch Fm >Sg 34 M NH Greenvale Cove Fm >Sm 33 M NH Madrid Fm >Ssf 32s M NH Smalls Falls Fm >Smsf 32s M NH Madrid and Smalls Falls Fms, > undifferentiated >Sp 32 M NH Perry Mtn Fm >Spr 32s M NH Perry Mtn and Rangeley Fms, > undifferentiated >Spv 43 M NH Perry Mtn Fm >Spp 31 M NH Perry Mtn Fm >Sc 34 M NH Clough Quartzite >Sfc 33c B NH Fitch Fm and Clough Quartzite, > undifferentiated >Sr 33s M NH Rangeley Fm >Sru 33s M NH Rangeley Fm >Sruc 33 M NH Rangeley Fm >Srl 33 M NH Rangeley Fm >Srv 42 M NH Rangeley Fm >Srvb 42 M NH Rangeley Fm >Srmr 42 M NH Rangeley Fm >Srgm 42s M NH Rangeley Fm >Srg 32s M NH Rangeley Fm >SOf 31 B NH Frontenac Fm >SOfb 42 B NH Frontenac Fm >SOff 61v B NH Frontenac Fm >SOfv 61v B NH Frontenac Fm >S1b 61 B NH biotite granite to granodiorite dikes >So1b 61 B NH granite >Oo3B-6 61 B NH trondhjemite and quartz diorite >Oo1b 61 B NH biotite granite >Oo1h 61 B NH hornblende-biotite granite >Oo1-3A 61 B NH granite, granodiorite, and tonalite >Oo1-3B 61 B NH granite, granodiorite, and trondhjemite >Oo9h 44 B NH hornblende gabbro >Oo2b 61 B NH granodiorite >Oo2-3A 61 B NH granodiorite to tonalite >Oo3A 61 B NH tonalite >Oo3B 61 B NH trondhjemite >Oo4C 61 B NH hornblende quartz monzonite >Oo4-7h 62 B NH hornblende quartz syenite to syenite >Oo7h 62 B NH hornblende-biotite syenite >Oo9Bh 44 B NH hornblende gabbro >Sh1b 61 B NH granites of East Inlet stock >Oh2-3A 61 B NH hornblende-chlorite granodiorite or > tonalite >Oh2-9A 61 B NH tonalite, diorite, granodiorite, and > granite >Oa 42,61v B NH Ammonoosuc Volcanics >Oal 42 B NH Ammonoosuc Volcanics >Oau 42 B NH Ammonoosuc Volcanics >Oaub 42 B NH Ammonoosuc Volcanics >Oaux 42 B NH Ammonoosuc Volcanics >DOg 33 C NH Gile Mtn Fm >DOgm 31 C NH Gile Mtn Fm, Meetinghouse Slate Mbr >DOgc 33c C NH Gile Mtn Fm >DOgp 32 C NH,VT Gile Mtn Fm >DOgpf 32 C NH,VT Gile Mtn Fm >DOgg 32 C NH,VT Gile Mtn Fm >DOggp 32 C NH,VT Gile Mtn Fm >DOgv 42 C NH,VT Gile Mtn Fm >DOghs 32 C NH,VT Gile Mtn Fm, Grits at Hall Stream >SOw 33c C NH Waits River Fm >Sg 33 B NH Greenvale Cove Fm >Oq 32s B NH Quimby Fm >Op 32s B NH Partridge Fm >Od 32s B NH Dixville Fm >OCd 34 B NH Dead River Fm >Zsgg 61 Z RI Sterling Plutonic Group (Sterling Plutonic > Suite) >Zsag 61 Z RI Sterling Plutonic Group (Sterling Plutonic > Suite) >Zsmg 43 Z RI Sterling Plutonic Group (Sterling Plutonic > Suite) >Zp 34 Z RI Plainfield Fm >Zeag 61 Z RI Esmond Igneous Suite (Esmond Plutonic > Suite) >Zegg 61 Z RI Esmond Igneous Suite (Esmond Plutonic > Suite) >Zem 44 Z RI Esmond Igneous Suite (Esmond Plutonic > Suite) >Zbm 42 Z RI Blackstone Group >Zbs 33c Z RI Blackstone Group >Zbu 43 Z RI Blackstone Group >DZgd 44 Z RI gabbro and(or)diorite >Dsg 61 Z RI Scituate Igneous Suite (Scituate Granite) >Dsfg 61 Z RI Scituate Igneous Suite (Scituate Granite) >Zwm 43 Z RI Waterford Group, Mamacoke Fm >Zwr 43 Z RI Waterford Group, Rope Ferry Gneiss >Png 61 Z RI Narragansett Pier Plutonic Suite >Pnfg 61 Z RI Narragansett Pier Plutonic Suite >Jm 50 Z RI monchiquite >OCst 12 S NY Stockbridge Marble >Cw 12 S NY Wappinger Group, Briarcliff Dolostone >OCs 12 S NY carbonate rocks >Ow 12 S NY Wappinger Group, Copake Fm, Rochdale Fm, > and Halycon Dolostone >Cev 32 T NY Everett Schist >Om 32 T NY Manhattan Fm, undifferentiated >Owl 32s S NY Walloomsac Fm >Oba 12s S NY Balmville Limestone >Cpg 34 Y NY Poughquag Quartzite >bg 61 X NY biotite granitic gneiss >mug 43 Y NY metasedimentary rock and granitic gneiss, > interlayed >Oag 31 X NY Austin Glen Fm >Ohr 43 H NY Harrison Gneiss >f 61 Y NY Fordham Gneiss, undifferentiated >OCi 12 S NY Inwood Marble >Oht 61,33 X NY Hartland Fm >Os 50 X NY serpentinite >Ob 61 X NY Bedford Gneiss >am 43 Y NY amphibolite, pyroxenic amphibolite, > hornblende gneiss >rg 33s X NY biotite-quartz-feldspar gneisses >Dco 33c - QE Compton Fm >D1b 61 - QE biotite granite >D1-2b 61 - QE biotite granite and granodiorite >Dsi 32 - QE Ironbound Mtn Fm >Dsih 42 - QE Ironbound Mtn Fm - Grit lenses at Halls > Stream

Progress: Complete
Update Frequency: There are no planned changes to this data layer.

Theme Keywords: None, lithogeochemical, bedrock, 1:125, NAWQA, Connecticut River, inlandWaters
Place Keywords: Connecticut, Housatonic, Thames, and Coastal River Basins, CONN NAWQA Study Area

Access Constraints: None
Usage Constraints: About 95 percent of this data layer was compiled and digitized at a scale of 1:125,000, and should be used at or near this scale. Other limitations, listed below, include source variety, inherent source limitations, and other limitations. (a) Source variety: Compilation of the lithogeochemical data layer using State geologic maps resulted in some discontinuities at State borders. The lithogeochemical code assigned to a rock unit was based primarily on its description on the appropriate State geologic map. Because the information contained on the individual State maps was interpreted and assembled during a 40-year period by different groups of geologists, the maps do not always represent a coherent, or consistent, data set when combined. In addition, the chemical and mineral-assemblage characteristics of the rock groups and formations within each State are generalized in the geologic map descriptions; thus, regional trends in lithology or metamorphic grade may have resulted in different generalized descriptions of the same geologic unit in adjacent States. Discrepancies across State borders in the lithogeochemical coverage reflect these and other inconsistencies among the State geologic maps that could not be resolved with the existing information. However, the lithogeochemical coding of geologic units is internally consistent within each State, and discrepancies across State boundaries are minor in most cases. (b) Inherent limitations of data sources: Most of the lithogeochemical source material was compiled into the data layer from 1:125,000 mylar overlays or enlargements of State geologic maps (Massachusetts and Connecticut) or from enlargements of 1:250,000 U.S. Geological Survey topographic quadrangles with geologic contact lines (New Hampshire and Vermont). Thus, the lithogeochemical source materials include the limitations of the individual State maps and their source or base maps. In the case of the Massachusetts geologic map, the base map included two separate 1:250,000 U.S. Geological Survey topographic maps that had been matched at their edges and enlarged to 1:125,000 (the map was compiled at 1:125,000 but published at 1:250,000). Errors associated with these base-map construction procedures were evident when the lithogeochemical source sheet of Massachusetts was digitized. The initial root mean square (RMS) error, a measure of the accuracy of the registration of the digitized data to real-world locations, of the digitized lithogeochemical sheet was outside of the ideal range (less than or equal to 0.004) for digital cartographic products. Thus, the Massachusetts source sheet was digitized as four separate quadrants (northwestern, southwestern, northeastern, and southeastern) with separate sets of registration marks ("tics" in ARC/INFO); two quadrants approximately corresponded to each of the original two 1:250,000 edgematched topographic source-base maps. The RMS error for three of the four digitized quadrats was less than 0.004. For the southeast quadrant, the RMS error, at 0.009, was slightly higher than normally acceptable but was the best that could be obtained using the source geologic map. Small areas of Connecticut along Long Island Sound are not mapped in the lithogeochemical coverage, which reflect the extent of geologic information shown in Rogers (1985). (c) Other limitations: The 29-unit lithogeochemical classification scheme presented in this data layer has not been tested using actual water-quality data. The classification scheme and associated expected water-quality and ecosystem characteristics were based on geologic and geochemical principles and previous studies of the relations of rock type and these characteristics. Comparison with actual water-quality data likely would result in refinement of the classification scheme and a better understanding of the relations among rock types and water-quality and ecosystem characteristics. The classification scheme and data layer are intended to provide a general, flexible framework for classifying and mapping bedrock types in the study area for all types of water-quality analysis. The data layer is primarily a lithologic map, but with lithologic classes that are defined with respect to their potential effects on water quality. It is left to the user to define the specific water-quality question to be addressed and, if necessary, to regroup the 29 lithogeochemical rock types as appropriate to his or her analysis. For example, if sensitivity to acid deposition were the question being considered, the 29 lithogeochemical rock types might be grouped into three or more classes of low, moderate, and high sensitivity. The data layer primarily depicts the lithogeochemical character of bedrock units, rather than of surficial deposits such as glacial till, glacial outwash, or recent alluvium. Where surficial deposits are derived from the local bedrock, the data layer might also be used to describe the lithogeochemical character of these materials. However, chemical characteristics of natural waters associated with surficial deposits may differ from that suggested by the lithogeochemical character of the bedrock units to the extent that the surficial deposits consist of or are mixed with materials transported from source areas with differing lithogeochemical characteristics. Comparison of ground-water quality in surficial deposits overlying four generalized bedrock types-- carbonates (11 and 12), calcareous clastic rocks (13), Mesozoic-basin or arkosic rocks (21, 21cs, 22, and 23), and crystalline rocks (all other lithogeochemical codes)--found significant differences in specific conductance, pH, dissolved oxygen, alkalinity, dissolved solids, carbonate hardness, and major ions among the four bedrock types (Grady, S.J., and Mullaney, J.R., 1998, Natural and human factors affecting shallow water quality in surficial aquifers in the Connecticut, Housatonic, and Thames River Basins, U.S. Geological Survey Water-Resources Investigations Report 98-4042, 81 p).