Bibliographic Citation
| Document | For copies of Journal Articles, please contact the Publisher or your local public or university library and refer to the information in the Resource Relation field. For copies of other documents, please see the Availability, Publisher, Research Organization, Resource Relation and/or Author (affiliation information) fields and/or Document Availability. |
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| Title | Structural and petrologic characteristics of the Taconian-Acadian overprint zone in Massachusetts and Vermont |
| Creator/Author | Armstrong, T.R. (Virginia Tech, Blacksburg, VA (United States). Dept. of Geological Sciences) ; Hames, W.E. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Earth, Atmospheric, and Planetary Sciences) |
| Publication Date | 1993 Mar 01 |
| OSTI Identifier | OSTI ID: 5934270 |
| Report Number(s) | CONF-9303211-- |
| Other Number(s) | ISSN0016-7592; CODEN: GAAPBC |
| Resource Type | Conference |
| Specific Type | Journal Article |
| Resource Relation | Geological Society of America, Abstracts with Programs ; Vol/Issue: 25:2; 28. annual Geological Society of America (GSA) Northeastern Section meeting; 22-24 Mar 1993; Burlington, VT (United States) |
| Subject | 580000 -- Geosciences; GEOLOGIC DEPOSITS-- GEOTHERMOMETRY;GEOLOGIC DEPOSITS-- ISOTOPE DATING;GEOLOGIC DEPOSITS-- PETROLOGY;MASSACHUSETTS-- GEOLOGIC DEPOSITS;METAMORPHIC ROCKS-- GEOTHERMOMETRY;METAMORPHIC ROCKS-- ISOTOPE DATING;METAMORPHIC ROCKS-- PETROLOGY;VERMONT-- GEOLOGIC DEPOSITS; GEOBAROMETRY;GEOLOGIC HISTORY;GEOTHERMOMETERS;METAMORPHISM |
| Related Subject | AGE ESTIMATION;DEVELOPED COUNTRIES;GEOLOGY;MEASURING INSTRUMENTS;NORTH AMERICA;ROCKS;THERMOMETERS;USA |
| Description/Abstract | Structural and petrologic relationships from two regions of the New England Taconide Zone provide distinction of Taconian and Acadian deformation fabrics and related metamorphisms.^In SW Massachusetts, Taconian metamorphism increases eastward from chlorite- to kyanite-grade, with staurolite zone Zr hb plateau ages of [approx]445 Ma.^Within the Acadian fibrolite zone, Ar cooling ages are related to a thermal maximum at 390--400Ma, coeval with crenulation cleavage that deforms Taconian fabrics.^Taconian and Acadian metamorphic regimes are separated by a 4 km-wide zone in which polymetamorphic assemblages exist but yield consistent Acadian mineral-rim P-T data, and Acadian structures are pervasive.^In southern Vermont, the overlap zone is broad ([approx]30 km); undisturbed Taconian Ar K-feldspar cooling ages occur on the west side of the Green Mountain massif.^Farther east, Taconian fabric is almost completely obliterated by dynamic Acadian metamorphism, and is truncated and retrograded in areas adjacent to a major Acadian thrust zone.^The upper plate rocks, including the Barnard Belt and the Silurian-Devonian sequences (the CVB), do not contain Taconian fabrics, the early Acadian deformations, or retrogression, and are associated with garnet-to-kyanite-grade Acadian metamorphism and a coeval, regionally dominant deformation, both of which are younger than 390Ma and older than 373Ma. |
| Country of Publication | United States |
| Language | English |
| Format | Pages: 3 |
| System Entry Date | 2001 May 13 |
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Last Updated: 02/08/2009