Immature plate boundary zones studied with a submersible in the Gulf of California

Research Article| September 01, 1980 Immature plate boundary zones studied with a submersible in the Gulf of California PETER LONSDALE; PETER LONSDALE 1University of California, San Diego, Marine Physical Laboratory of Scripps Institution of Oceanography, La Jolla, California 92093 Search for other works by this author on: GSW Google Scholar L. A. LAWVER L. A. LAWVER 1University of California, San Diego, Marine Physical Laboratory of Scripps Institution of Oceanography, La Jolla, California 92093 Search for other works by this author on: GSW Google Scholar Author and Article Information PETER LONSDALE 1University of California, San Diego, Marine Physical Laboratory of Scripps Institution of Oceanography, La Jolla, California 92093 L. A. LAWVER 1University of California, San Diego, Marine Physical Laboratory of Scripps Institution of Oceanography, La Jolla, California 92093 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1980) 91 (9): 555–569. https://doi.org/10.1130/0016-7606(1980)91<555:IPBZSW>2.0.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 LONSDALE, L. A. LAWVER; Immature plate boundary zones studied with a submersible in the Gulf of California. GSA Bulletin 1980;; 91 (9): 555–569. doi: https://doi.org/10.1130/0016-7606(1980)91<555:IPBZSW>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 The two spreading axes and a marginal transform fault in Guaymas Basin were examined during six dives to depths of 1,900 to 2,000 m in the submersible Sea Cliff. The plate boundary zones differ from those at mid-ocean ridges because of their youth: they are buried by thick sediment, partly derived from the adjacent continents whose rifted edges are still at the plate boundary along some transform faults. The accretionary margins have rift valleys bounded by normal fault scarps of diatomaceous mud; they are true grabens, not regenerating axial troughs like those at some mid-ocean ridges. The rifts are the main sites of turbidite deposition, igneous intrusion, and extensional faulting, processes that compete to level, buckle, and fracture the rift floors. Intrusion is by emplacement of sills and thicker bysmalith-like bodies, which episodically raise hills of folded and faulted semiconsolidated turbidites. Some of the fault scarps bounding the hills have very fresh, near-vertical faces, while others are cavernously weathered. A small hill within the Northern Trough has extensive young hydrothermal deposits of talc and sulfides on its crest and at a dissecting fault scarp. No extrusive volcanic rocks were found in the axial rift valleys nor at a marginal transform fault, where a belt of obliquely faulted sediments probably overlies the strike-slip axis. The transform-fault shear zone lies in a very asymmetric graben, with a sag at the edge of the basin floor and a fresh fault scarp truncating lithified sandstones on the continental side. 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.