STRUCTURAL PETROLOGY OF THE WISSAHICKON SCHIST NEAR PHILADELPHIA, PENNSYLVANIA

Abstract

Research Article| September 01, 1950 STRUCTURAL PETROLOGY OF THE WISSAHICKON SCHIST NEAR PHILADELPHIA, PENNSYLVANIA: WITH SPECIAL REFERENCE TO GRANITIZATION CHI-SHANG CH'IH CHI-SHANG CH'IH UNIVERSITY OF CALIFORNIA, BERKELEY, CALIF. Search for other works by this author on: GSW Google Scholar GSA Bulletin (1950) 61 (9): 923–956. https://doi.org/10.1130/0016-7606(1950)61[923:SPOTWS]2.0.CO;2 Article history received: 22 Jul 1949 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation CHI-SHANG CH'IH; STRUCTURAL PETROLOGY OF THE WISSAHICKON SCHIST NEAR PHILADELPHIA, PENNSYLVANIA: WITH SPECIAL REFERENCE TO GRANITIZATION. GSA Bulletin 1950;; 61 (9): 923–956. doi: https://doi.org/10.1130/0016-7606(1950)61[923:SPOTWS]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract This paper is a comparative study of the fabrics of granitized and ungranitized Wissahickon schists near Philadelphia.Granitization was effected chiefly by the introduction of alkalis and some lime, probably carried in hydrothermal solutions. The mica schists were reconstituted, becoming coarser in grain, with relative increase in feldspars and decrease in micas. A complementary enrichment of less-granitized patches and narrow border zones in iron and magnesia has produced biotite-rich rocks. Hydrothermal activity following the main period of granitization has produced some retrograde metamorphism.Folding in the ungranitized schist is of the flexural slip type. The development of folds can be traced in both mica and quartz fabrics, and the rotation of S-surf aces in the fabrics can be correlated with the overturned folds observed in the field. The same features can be identified in the granitized rocks, but less distinctly, since the physical properties of the latter made them react differently from the ungranitized schists during regional metamorphism. Granitization was syntectonic.Late movements, occurring after the main period of granitization, are recorded locally in the sheared or crushed rocks. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.