Extensional Tectonics of the Southwestern United States PDF Download

Author: Larry Mayer
Publisher: Geological Society of America
ISBN: 081372208X
Category : Science
Languages : en
Pages : 131

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Author: Larry Mayer
Publisher:
ISBN:
Category : Geology, Structural
Languages : en
Pages : 0

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Author: Geological Survey (U.S.)
Publisher:
ISBN:
Category : Geology
Languages : en
Pages : 272

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Proceedings of a workshop held at the Desert Research Center, Soda Springs (Zzyzx), California, February 9-12, 1990.

Author:
Publisher:
ISBN:
Category : Earth (Planet)
Languages : en
Pages : 76

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Author: A.M.C. Sengör
Publisher: Springer Science & Business Media
ISBN: 9400922531
Category : Science
Languages : en
Pages : 722

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The ihsan Ketin NATO Advanced Study Institute on the Tectonic Evolution of the Tethyan Region was conceived in 1982 in Veszprem, Hungary, when three of the organizers (B. C. B. , L. H. R. and A. M. C. 9. ) had come together for a meeting on the tectonics of the Pannonian basin. All three of us had experience in the Tethyan belt and all three of us had been for some time deploring the lack of communication among workers of this immense orogenic belt. Much new work had been completed in such previously little-known areas as Turkey, Iran, Afghanistan, the People's Republic of China, the entire Himalayan region, as well as new work in the European parts of the chain. Also, ironically, parts of the belt had just been closed to field work for political reasons, so it seemed as if the time was right to sit back and consider what had been done so far. Because the Istanbul group had had an interest in the whole of the Tethyan belt and because that ancient city was more centrally locElted with excellent opportunities to see both Palaeo- and Neo-Tethyan rocks in a weekend excursion, we thought that Istanbul was a natural place for such a meeting, not mentioning its own considerable attractions for the would-be contributors. A happy coincidence was that Prof.

Author: Suzanne Hecker
Publisher: Utah Geological Survey
ISBN: 1557910944
Category : Earthquake hazard analysis
Languages : en
Pages : 117

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This report consolidates and synthesizes information on Quaternary faulting, folding, and volcanism in Utah and characterizes recent tectonic activity throughout the state. The primary purpose is to provide a comprehensive reference on fault-specific seismic sources and surface rupture to facilitate the evaluation of earthquake hazards in Utah. Two 1:500,000-scale maps show Quaternary tectonic features categorized according to probable ages of most recent surface deformation and ages of volcanic rocks. Two appendix tables summarize significant data on the activity of mapped features, including ages of surface displacements and volcanism, slip rates, recurrence intervals, displacement amounts, and lengths of surface ruptures. Good age control and quantitative activity data are available for relatively few tectonic features in Utah and detailed work is needed in many areas of the state. 157 pages + 2 plates

Author: Andrew Barth
Publisher: Geological Society of America
ISBN: 9780813723655
Category : Science
Languages : en
Pages : 338

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Author: National Research Council
Publisher: National Academies Press
ISBN: 0309029287
Category : Science
Languages : en
Pages : 211

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Author: Brian P. Wernicke
Publisher: Geological Society of America
ISBN: 0813711762
Category : Science
Languages : en
Pages : 540

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Author: William R. Dickinson
Publisher: Geological Society of America
ISBN: 9780813722641
Category : Science
Languages : en
Pages : 130

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Mid-Tertiary strata exposed as tilted homoclines along the flanks of the San Pedro trough and across broad uplands north of the Catalina core complex are assigned to the following formations, each of which includes informal local members and facies: (a) Mineta Formation, mid-Oligocene redbeds including both conglomeratic fluvial and finer-grained lacustrine deposits; (b) Galiuro Volcanics, including lavas and domes, air-fall and ash-flow tuffs, and intercalated volcaniclastic strata of late Oligocene to earliest Miocene age; (c) Cloudburst Formation, also of late Oligocene and earliest Miocene age but including a sedimentary upper member of conglomeratic strata as well as a volcanic lower member correlative with part of the Galiuro Volcanics; and (d) San Manuel Formation, composed of lower Miocene alluvial fan and braidplain deposits that display contrasting clast assemblages in different areas of exposure. Generally correlative Oligocene-Miocene strata exposed south of the Catalina core complex are assigned to the Pantano Formation, which contains similar lithologic components. Less-deformed Neogene strata of post-mid-Miocene basin fill are assigned to the Quiburis Formation along the San Pedro trough, but stratigraphic equivalents elsewhere lack adequate nomenclature. High benchlands mantled by paleosols mark the highest levels of Neogene aggradation. Successive stages of subsequent erosional dissection are recorded by multiple terrace levels incised into basin fill. Key exposures of syntectonic mid-Tertiary sedimentary sequences in several local subareas reveal typical structural and stratigraphic relationships. Multiple fault blocks expose pre-Tertiary bedrock overlain by tilted mid-Tertiary strata confined to intervening half-grabens. Bounding syndepositional faults dip southwest and associated homoclines dip northeast. Fanning dips and buttress unconformities reflect progressive tilt and burial of eroding fault blocks. Dips of block-bounding faults are inversely proportional to the ages of the faults. Steeper dips for younger faults suggest either progressive erosion of successive listric faults or progressive rotation of successive planar faults. Uniformly moderate to steep dihedral angles between fault surfaces and offset homoclinal bedding imply that the faults dipped more steeply near the surface when syntectonic mid-Tertiary strata were subhorizontal. Although the inference of listric faulting best links apparent strands of the Catalina detachment system, the alternate interpretation of rotational normal faulting is compatible with local structural relationships including tilt of porphyry copper orebodies. Within the San Pedro trough, multiple homo clines of mid-Tertiary strata are exposed locally in tilt-blocks exhumed by Neogene erosion from beneath nearly flat-lying basin fill of the Quiburis Formation. Faults bounding the mid-Tertiary exposures include backtilted strands of the Catalina detachment system, somewhat younger listric or rotational normal faults, and steeper basin-range normal faults that display offsets both synthetic and antithetic to the flanks of the San Petro trough. In Cienega Gap, flanking the Tucson Basin, multiple tilt-blocks of the Pantano Formation form part of the upper plate of the Catalina detachment system. Initial construction of alluvial fans by generally westward paleoflow was followed by ponding of lacustrine environments along the foot of secondary breakaway scarps that also generated massive megabreccia deposits. In summary, syntectonic Oligocene to Miocene sedimentation succeeded a prominent pulse of polymodal mid-Tertiary volcanism and was coeval with mylonitic deformation and detachment faulting along the flank of the Catalina core complex. The headwall rupture for the detachment system migrated westward from an initial position along the range front of the Galiuro Mountains. After mid-Miocene time, accumulation and subsequent dissection of essentially undeformed basin fill was accompanied by basin-range block faulting. The most challenging structural issue is whether fault strands of the Catalina detachment system are interconnected or are disconnected rotational segments.