Structural geology of the upper plate of the Bullfrog Hills detachment fault system, southern Nevada

Research Article| July 01, 1990 Structural geology of the upper plate of the Bullfrog Hills detachment fault system, southern Nevada FLORIAN MALDONADO FLORIAN MALDONADO 1U.S. Geological Survey, MS. 913, Box 25046, Denver Federal Center, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1990) 102 (7): 992–1006. https://doi.org/10.1130/0016-7606(1990)102<0992:SGOTUP>2.3.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation FLORIAN MALDONADO; Structural geology of the upper plate of the Bullfrog Hills detachment fault system, southern Nevada. GSA Bulletin 1990;; 102 (7): 992–1006. doi: https://doi.org/10.1130/0016-7606(1990)102<0992:SGOTUP>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 An extremely distended terrane containing two detachment faults and an overlying complex of normal faults is exposed in the Bullfrog Hills, southern Nevada. Shallow crustal rocks have been extended along the detachment faults by listric and planar-rotational normal faults. The detachment faults define three structurally discordant plates. The lower detachment fault separates a lower plate of metamorphosed Late Proterozoic rocks from an overlying middle plate, composed of slivers of lower and middle Paleozoic clastic and carbonate rocks. The middle-plate rocks are brecciated and essentially unmetamorphosed, and the stratigraphic succession is incomplete and highly attenuated. The upper detachment fault separates the middle-plate rocks from an upper-plate succession of block-faulted Miocene volcanic, volcaniclastic, and sedimentary rocks.Miocene rocks of the upper plate dip at moderate to steep angles into the upper detachment fault, or, where the middle plate has been tectonically removed, into the lower detachment fault. The rocks are broken, tilted, and repeated in blocks bounded by normal faults that terminate against, or flatten and merge into, the upper detachment fault or, where the middle plate has been removed, the lower detachment fault. The normal faults in the upper plate are (1) planarrotational faults that form imbricate map patterns and (2) listric faults that are characterized by oval and horseshoe map patterns. These fault map patterns may be due to (1) curvilinear intersection of a listric or planar fault with an antithetic fault, (2) complex intersection of two or more faults of different ages, (3) rotated listric faults, (4) extremely rotated planar normal faults that resemble listric faults, (5) nearly flat-lying normal faults, or (6) topographic and erosional effects.Attenuation of the Late Proterozoic and Paleozoic strata indicates large movement on the detachment faults; the upper plate has been extended more than 100% and possibly more than 275% locally. The geometry of the normal faults and the repetition and dip direction of the Miocene rocks indicate that major extension, at least of the upper plate, was west-northwest-east-southeast and occurred mostly between about 10 and 8 Ma. 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.