Fry analysis on K-feldspar megacryst distribution within the Papoose Flat pluton, Inyo Mountains, California
- Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Geology and Geophysics
- Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences
Fry analysis on the distribution of k-feldspar megacrysts in twelve outcrop faces of deformed Papoose Flat granite reveal weakly defined ellipses that are oriented oblique to the foliation. Foliation is parallel to the metasedimentary aureole contact and all outcrop faces that were measured were perpendicular to foliation and less than 20 m from the contact. The well developed foliation is defined by alignment of tabular k-feldspar megacrysts, micas, and ribbons of quartz. Seven Fry analyses, from both the N and S sides of the pluton, reveal ellipses which are oriented approximately 15--45[degree] to the foliation, top to the NNE, and range from moderately well defined ellipses to poorly defined. Two analyses reveal moderately well defined ellipses which are subparallel to the foliation and three analyses reveal no identifiable ellipses. Most Fry ellipses have aspect ratios ranging from 2--3. The ellipses are defined by areas of few to no points with little to no surrounding girdle of maximum concentration, indicating that the k-feldspar megacryst distribution within the granite was weakly anticlustered before deformation. The poor definition of most of the ellipses is consistent with the macroscopic observation of clustering in the deformed state and also suggests that the predeformation distribution was weakly anticlustered. Although ellipses are weakly defined, most are similarly oriented with respect to the foliation, suggesting that they represent real ellipses that are related to strain within the granite. It is possible that the ellipses are unrelated to the present solid state foliation, and therefore unreliable as a kinematic indicator. One possible explanation is that the ellipses represent an earlier foliation developed in the magmatic state, which was overprinted as the pluton cooled and deformation continued in the solid state.
- OSTI ID:
- 5018924
- Report Number(s):
- CONF-9305259--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:5; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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