Petrology and structure of the Glen Quadrangle, southeastern Adirondacks, NY

<p>An outcrop geologic map of The Glen quadrangle has been produced at a scale of 1:24,000. This quadrangle is composed of a sequence of Precambrian rocks which were deformed and recrystallized under clinopyroxene-garnet granulite facies conditions during late Precambrian time. Metasedimentary rocks include calcic and dolomitic marble, metapelites, and metaquartzites. Rocks of known igneous origin include metagabbros, a metanorthosite-anorthositic metagabbro series, and minor unmetamorphosed diabase intrusives. In addition, there are a variety of mineralogically and texturally subdivided granitic-charnockitic gneisses of unknown origin. These rock sequences are correlated, where possible, with previous work in surrounding areas.</p> <p>Estimates have been made of temperature and pressure conditions Hill during metamorphism. These are based on (1) the presence of sillimanite as the only aluminosilicate phase in the pelitic metasediments, and (2) a series of corona reactions in the olivine metagabbros which resulted in the formation of orthopyroxene + clinopyroxene + spinel, and garnet. The additional presence of associated garnet + clinopyroxene in other rock types precludes the possibility of the coronas having formed in cooling intrusives at temperatures higher than the surrounding rocks. Published experimental evidence, combined with field data, suggests temperatures and pressures of about 800-850° C. and 7-9 kb., and low P_H2O.</p> <p>A structural interpretation has been made which suggests a minimum of three superposed deformational events during metamorphism. An early isoclinal folding event (F1) was accompanied by the formation of an S1 foliation. The second event (F2) produced tight to open folds, and in some areas, an S2 foliation. The third event (F3) produced a broad warping of S2, and probably produced most of the mineral lineations in the quadrangle. A later event at low temperature and pressure produced numerous breccia zones, some of which have been interpreted as normal faults.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Geological Sciences

Year

1976

Author dc:creator

• Farrar, Stewart Smith

Contributors dc:contributor

• Rosemary J. Vidale
• Herman E. Roberson
• William D. MacDonald

• Petrology
• New York (State)
• Adirondack Mountains
• Geology
• Structural

Repository record dc:identifier

https://orb.binghamton.edu/dissertation_and_theses/346

OAI identifier oai:identifier

oai:orb.binghamton.edu:dissertation_and_theses-1351