Cordilleran Metamorphic Core Complexes

Cordilleran Metamorphic Core Complexes
Title Cordilleran Metamorphic Core Complexes PDF eBook
Author Max D. Crittenden
Publisher Geological Society of America
Pages 497
Release 1980
Genre Science
ISBN 0813711533

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Tectonic Setting of Faulted Tertiary Strata Associated with the Catalina Core Complex in Southern Arizona

Tectonic Setting of Faulted Tertiary Strata Associated with the Catalina Core Complex in Southern Arizona
Title Tectonic Setting of Faulted Tertiary Strata Associated with the Catalina Core Complex in Southern Arizona PDF eBook
Author William R. Dickinson
Publisher Geological Society of America
Pages 130
Release 1991
Genre Science
ISBN 9780813722641

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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.

Geologic Excursions in Southwestern North America

Geologic Excursions in Southwestern North America
Title Geologic Excursions in Southwestern North America PDF eBook
Author Philip A. Pearthree
Publisher
Pages 553
Release 2019
Genre Geology
ISBN 9780813756554

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Ecosystem Dynamics in a Polar Desert

Ecosystem Dynamics in a Polar Desert
Title Ecosystem Dynamics in a Polar Desert PDF eBook
Author
Publisher American Geophysical Union
Pages 224
Release 1998
Genre Desert ecology
ISBN 9780875905

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Presents information from the primary abiotic forces defining the system, and from the present hydrology, biogeochemistry and physics of major sites of organic carbon production of the McMurdo Dry Valleys. Additionally, research on the physical, chemical, and biological properties of the dry valley soils is included. The role of environmental management in long-term ecological studies is also addressed. The accompanying CDROM provides details and scale to visualize the McMurdo Dry Valleys from an ecosystem perspective.

Cordilleran Section of the Geological Society of America

Cordilleran Section of the Geological Society of America
Title Cordilleran Section of the Geological Society of America PDF eBook
Author Mason L. Hill
Publisher Geological Society of America
Pages 505
Release 1987
Genre Science
ISBN 0813754011

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Laurentia

Laurentia
Title Laurentia PDF eBook
Author Steven J. Whitmeyer
Publisher Geological Society of America
Pages 824
Release 2023-01-04
Genre Science
ISBN 0813712203

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"This Memoir focuses on 7 'turning points' that had specific and lasting impacts on Laurentian evolution: The Neoarchean, characterized by cratonization; the Paleoproterozoic and the initial assembly of Laurentia; the Mesoproterozoic southern margin of Laurentia; the Midcontinent rift and the Grenville orogeny; (5) the Neoproterozoic breakup of Rodinia; the mid-Paleozoic phases of the Appalachian-Caledonian orogen; and the Jurassic-Paleogene assembly of the North American Cordillerar"--

Bibliography and Index of the Geology and Mineral Resources of Washington, 1963-1980

Bibliography and Index of the Geology and Mineral Resources of Washington, 1963-1980
Title Bibliography and Index of the Geology and Mineral Resources of Washington, 1963-1980 PDF eBook
Author Connie Manson
Publisher
Pages 416
Release 1983
Genre Geology
ISBN

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