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 | Evidence for fourth generation structures in the Piedra Lumbre region, Western Picuris Mountains, New Mexico |
| Creator/Author | Chernoff, C.B. ; Helper, M.A. ; Mosher, S. (Univ. of Texas, Austin, TX (United States). Dept. of Geological Sciences) |
| Publication Date | 1993 Feb 01 |
| OSTI Identifier | OSTI ID: 6138785 |
| Report Number(s) | CONF-9303212-- |
| 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: 25:1; 27. annual Geological Society of America (GSA) South-Central Section meeting; 15-16 Mar 1993; Fort Worth, TX (United States) |
| Subject | 580000 -- Geosciences; GEOLOGIC STRUCTURES-- GEOLOGIC HISTORY;GEOLOGIC STRUCTURES-- GEOLOGY;NEW MEXICO-- GEOLOGIC STRUCTURES; GEOLOGIC FORMATIONS;METAMORPHIC ROCKS;METAMORPHISM;MINERALOGY;PETROLOGY;PRECAMBRIAN ERA;RECRYSTALLIZATION;STRATIGRAPHY |
| Related Subject | DEVELOPED COUNTRIES;GEOLOGIC AGES;GEOLOGY;NORTH AMERICA;ROCKS;USA |
| Description/Abstract | Mid-Proterozoic Hondo Group metasediments in the western Picuris Mountains, New Mexico clearly display 3 generations of previously recognized penetrative, synmetamorphic structures and a previously undocumented forth generation of overprinting folds with an associated axial planar foliation.^The earliest structures include: (1) a bedding-parallel S[sub 1] foliation and rare, rootless, intrafolial F[sub 1] folds; (2) north-verging, west-trending F[sub 2] folds and an axial planar metamorphic foliation (S[sub 2]); (3) a steeply dipping, N-S striking crenulation cleavage (S[sub 3]).^In the Piedra Lumbre region, southwest-plunging, open, upright chevron and box folds (F[sub 4]) locally reorient F[sub 2], S[sub 2] and S[sub 3] crenulations.^The largest F[sub 4] folds in the Piedra Lumbre region have half-wavelengths of 500 meters.^An associated nearly vertical foliation (S[sub 4]) overprints the first three foliations.^The S[sub 4] foliation is a crenulation cleavage in micaceous layers and a discontinuous alignment of biotite laths in quartzose layers.^Crystallization of biotite during S[sub 4] and chloritoid after S[sub 4], along with static recrystallization and mineral replacement by chlorite, suggests this deformation occurred during the waning stages of mid-Proterozoic metamorphism.^The orientation of F[sub 2] and F[sub 4] folds are similar and both appear to occur on a regional scale.^Interference of open upright F[sub 4] folds and tight, north-verging, overturned F[sub 2] folds produces a geometry that resembles that of the kilometer-scale Copper Hill Anticline of the western Picuris Mountains, previously interpreted to be solely the result of F[sub 2] folding. |
| Country of Publication | United States |
| Language | English |
| Format | Pages: 6 |
| System Entry Date | 2001 May 13 |
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Last Updated: 02/08/2009