Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
Structural Evolution Of Djebel-Debadib Anticline : A Clue To The Regional Tectonic Style Of The Tunisian Atlas, Art Snoke, S. Schamel, R. M. Karasek
Structural Evolution Of Djebel-Debadib Anticline : A Clue To The Regional Tectonic Style Of The Tunisian Atlas, Art Snoke, S. Schamel, R. M. Karasek
Art Snoke
Djebel Debadib is a northeast trending anticline in the Tunisian Atlas, near El Kef, Tunisia. The core of the anticline consists of a deformed Triassic, gypsum-matrix breccia containing clasts of supratidal dolomite, terrigeneous clastic rocks, and ophites (metabasites). Locally, low-grade metasedimentary rocks, occurring as clasts in the evaporite, may represent fragments of basement rock plucked from salt subcrop during deep-seated flowage. The multiply deformed Triassic rocks are juxtaposed against Cretaceous or younger rocks, and Jurassic and Neocomian strata are not present in outcrop. These characteristics have been cited in many studies to suggest a history of diapirism to explain both …
Nature And Origin Of Seismic-Reflection Fabric, Ruby East Humboldt Metamorphic Core Complex, Nevada, P. A. Valasek, Art Snoke, C. A. Hurich, S. B. Smithson
Nature And Origin Of Seismic-Reflection Fabric, Ruby East Humboldt Metamorphic Core Complex, Nevada, P. A. Valasek, Art Snoke, C. A. Hurich, S. B. Smithson
Art Snoke
Seismic reflection profiling across exposed upper and middle crustal rocks of the Ruby-East Humboldt metamorphic core complex delineates important characteristics of the crustal structure developed during Tertiary extensional deformation. The goals of this study were to trace a Tertiary extensional shear zone from mylonitic surface outcrops into a seismic section and to characterize the deeper crustal fabric associated with the polyphase deformational history of the complex. Reflections in the shallow surface correlate with a plastic to brittle shear zone that formed during the tectonic unroofing of the middle crustal rocks. Constructive interference from strong planar layering in the mylonitic shear …
The Mesozoic-Cenozoic Tectonothermal Evolution Of The Ruby Mountains, East Humboldt Range, Nevada : A Cordilleran Metamorphic Core Complex, R. D. Dallmeyer, Art Snoke, E. H. Mckee
The Mesozoic-Cenozoic Tectonothermal Evolution Of The Ruby Mountains, East Humboldt Range, Nevada : A Cordilleran Metamorphic Core Complex, R. D. Dallmeyer, Art Snoke, E. H. Mckee
Art Snoke
A combined K-Ar and 40Ar/39Ar geochronological study of the Ruby Mountains-East Humboldt Range, Nevada, a Cordilleran metamorphic core complex, has revealed a complex tectonothermal history. The three structural subdivisions of the core complex (migmatitic core, mylonitic zone, and cover) share magmatic and deformational histories in part, but also display important contrasts in structural style, metamorphic paragenesis, and thermal history. During the Late Jurassic (ca 160 Ma), miogeoclinal rocks were polyphase-deformed, metamorphosed under amphibolite facies conditions, and pervasively intruded by peraluminous granitic magmas, thereby forming an igneous and metamorphic complex. Late Jurassic muscovite granite porphyry plugs also intruded unmetamorphosed cover rocks. …
Differential Stress, Strain Rate, And Temperatures Of Mylonitization In The Ruby Mountains, Nevada: Implications For The Rate And Duration Of Uplift, B. R. Hacker, A. Yin, J. M. Christie, Art Snoke
Differential Stress, Strain Rate, And Temperatures Of Mylonitization In The Ruby Mountains, Nevada: Implications For The Rate And Duration Of Uplift, B. R. Hacker, A. Yin, J. M. Christie, Art Snoke
Art Snoke
Knowledge of the magnitude of the differential stress during the formation of mylonitic rocks provides constraints on mechanical and thermal models for the exhumation of the metamorphosed foot walls of major low-angle detachment faults. We have analyzed the differential flow stress during the mylonitization of quartzose rocks in the Ruby Mountains, Nevada, using grain-size piezometers and kinetic laws for grain growth. Quartzites from mylonitic shear zones in Lamoille Canyon and Secret Creek gorge have grain sizes of 91–151 μm and 42–64 μm, respectively. The peak temperature during mylonitization was 630°±50°C, and analysis of grain-growth kinetics indicates that mylonitization continued during …
Thermochronologic Evidence Of Major Tectonic Denudation Associated With Detachment Faulting, Northern Ruby Mountains : East Humboldt Range, Nevada, R. K. Dokka, M. J. Mahaffie, Art Snoke
Thermochronologic Evidence Of Major Tectonic Denudation Associated With Detachment Faulting, Northern Ruby Mountains : East Humboldt Range, Nevada, R. K. Dokka, M. J. Mahaffie, Art Snoke
Art Snoke
Fission track (FT) thermochronology studies on igneous and metamorphic rocks from the Ruby Mountains-East Humboldt Range metamorphic core complex provide important constraints on the timing and nature of major mid-Tertiary extension in northeast Nevada. Rocks from within the Ruby-East Humboldt detachment (brittle-ductile normal-sense shear) zone were analyzed; the dominant lithology studied was variably mylonitic mafic orthogneiss. Nonmylonitic amphibolite from the top of the structurally lower migmatitic core and porphyritic biotite granodiorite from the Oligocene (circa 36 Ma) Harrison Pass pluton were also studied. FT ages on apatite, zircon, and sphene (except one 18.4-Ma apatite from the basal portion of the …