Research Article| October 01, 1993 Tilting, burial, and uplift of the Guadalupe Igneous Complex, Sierra Nevada, California PETER J. HAEUSSLER; PETER J. HAEUSSLER 1Earth Sciences Board and Institute of Tectonics, University of California, Santa Cruz, California 95064 Search for other works by this author on: GSW Google Scholar SCOTT R. PATERSON SCOTT R. PATERSON 2Department of Geological Sciences, University of Southern California, Los Angeles, California 90089-0740 Search for other works by this author on: GSW Google Scholar Author and Article Information PETER J. HAEUSSLER 1Earth Sciences Board and Institute of Tectonics, University of California, Santa Cruz, California 95064 SCOTT R. PATERSON 2Department of Geological Sciences, University of Southern California, Los Angeles, California 90089-0740 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1993) 105 (10): 1310–1320. https://doi.org/10.1130/0016-7606(1993)105<1310:TBAUOT>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation PETER J. HAEUSSLER, SCOTT R. PATERSON; Tilting, burial, and uplift of the Guadalupe Igneous Complex, Sierra Nevada, California. GSA Bulletin 1993;; 105 (10): 1310–1320. doi: https://doi.org/10.1130/0016-7606(1993)105<1310:TBAUOT>2.3.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 It is often incorrectly assumed that plutons have a relatively uneventful structural history after emplacement. The 151 Ma Guadalupe Igneous Complex (GIC) in the Foothills Terrane, California, was involved in three post-emplacement events: (1) ∼30° of southwestside-up tilting during ductile regional faulting and contraction, (2) burial of the pluton from ∼4 to 12 km during crustal thickening of the wall rocks, and (3) uplift with only minor tilting in the Late Cretaceous. Tilting of the pluton is indicated by (1) southwest to northeast gradational changes from layered gabbros and diorites to granites and granophyres; (2) northeastward dips of layering in gabbro, internal contacts, and bedding of overlying coeval(?) volcanic rocks; (3) northeastward decrease in wall-rock metamorphic grade; and (4) paleomagnetic data from 14 localities across the pluton. We argue that tilting occurred between 146-135 Ma during southwest-northeast-directed regional contraction. This contraction is indicated by widespread folds and cleavages and by reverse motion on the Bear Mountains fault zone (BMFZ), a large northeast-dipping shear zone that bounds the GIC on its southwest side. Burial of the GIC, which overlapped in time but outlasted tilting, is suggested by (1) post-emplacement contractional faulting, folding, and cleavage development; (2) analyses of strains associated with widespread cleavage that indicate vertical thickening of ∼100% and (3) microstructural and mineral assemblage data that indicate shallow emplacement of the GIC, in contrast to mineral assemblage and limited geobarometric data from adjacent 120-110 Ma plutons that indicate moderate emplacement levels. Late Cretaceous uplift is indicated by 95-75 Ma sedimentary rocks that unconformably overlie the 120-110 Ma plutons.This geologic history is interesting for several reasons. First, although the GIC participated in extensive post-emplacement deformation, it lacks internal structural evidence of these events, except locally along the Bear Mountains fault zone. Second, the agreement between paleomagnetic and structural evidence for tilting suggests that no large latitudinal displacement of the GIC is required. Third, the paleomagnetic data also help to define the geometry of the magma chamber now represented by the GIC. Lack of streaking of paleomagnetic site-mean directions demonstrates that the pluton acted as a single unit after cooling through the blocking temperature (450-560 °C) of low-titanium titanomagnetite; however, variations in the dip of internal layering and contacts, from 70° at the base to 30° near the top of the pluton, indicate that not all of these features were horizontal and planar when they formed. We propose that this variation in dip of layering is most consistent with sidewall crystallization of magma resulting in drape of layering along the walls of the intrusion. Therefore, internal layering within this pluton does not record paleohorizontal. 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.
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