scholarly journals Contemporary vertical velocity of the central Basin and Range and uplift of the southern Sierra Nevada

2008 ◽  
Vol 35 (20) ◽  
Author(s):  
Noah P. Fay ◽  
Richard A. Bennett ◽  
Sigrún Hreinsdóttir
Keyword(s):  
Sierra Nevada ◽  
Vertical Velocity ◽  
Basin And Range ◽  
Central Basin

Microseismicity and tectonics of the Nevada Seismic Zone

1971 ◽  
Vol 61 (5) ◽  
pp. 1413-1432 ◽  
Author(s):  
Frank J. Gumper ◽  
Christopher Scholz
Keyword(s):  
Sierra Nevada ◽  
Focal Mechanism ◽  
Basin And Range ◽  
Mono Lake ◽  
Tectonic Activity ◽  
Seismic Zone ◽  
Owens Valley ◽  
Western Basin ◽  
Focal Mechanism Solutions ◽  
Composite Focal Mechanism

abstract Microseismicity, composite focal-mechanism solutions, and previously-published focal parameter data are used to determine the current tectonic activity of the prominent zone of seismicity in western Nevada and eastern California, termed the Nevada Seismic Zone. The microseismicity substantially agrees with the historic seismicity and delineates a narrow, major zone of activity that extends from Owens Valley, California, north past Dixie Valley, Nevada. Focal parameters indicate that a regional pattern of NW-SE tension exists for the western Basin and Range and is now producing crustal extension within the Nevada Seismic Zone. An eastward shift of the seismic zone along the Excelsior Mountains and left-lateral strike-slip faulting determined from a composite focal mechanism indicate transform-type faulting between Mono Lake and Pilot Mountain. Based on these results and other data, it is suggested that the Nevada Seismic Zone is caused by the interaction of a westward flow of mantle material beneath the Basin and Range Province with the boundary of the Sierra Nevada batholith.

scholarly journals Two-phase westward encroachment of Basin and Range extension into the northern Sierra Nevada

Tectonics ◽  
2002 ◽  
Vol 21 (1) ◽  
pp. 2-1-2-10 ◽  
Author(s):  
Benjamin E. Surpless ◽  
Daniel F. Stockli ◽  
Trevor A. Dumitru ◽  
Elizabeth L. Miller
Keyword(s):  
Sierra Nevada ◽  
Basin And Range ◽  
Range Extension ◽  
Two Phase

Timing and synchrony of births in bighorn sheep: implications for reintroduction and conservation

2012 ◽  
Vol 39 (7) ◽  
pp. 565 ◽  
Author(s):  
Jericho C. Whiting ◽  
Daniel D. Olson ◽  
Justin M. Shannon ◽  
R. Terry Bowyer ◽  
Robert W. Klaver ◽  
...  
Keyword(s):  
Life History ◽  
Environmental Conditions ◽  
Release Site ◽  
Source Area ◽  
Bighorn Sheep ◽  
Basin And Range ◽  
Central Basin ◽  
Uinta Mountains ◽  
Life History Characteristics ◽  
Normalised Difference Vegetation Index

Context Timing (mean birthdate) and synchrony (variance around that date) of births can influence survival of young and growth in ungulate populations. Some restored populations of ungulates may not adjust these life-history characteristics to environments of release sites until several years after release, which may influence success of reintroductions. Aims We quantified timing and synchrony of births from 2005 to 2007 in four populations of reintroduced bighorn sheep (Ovis canadensis) occupying two ecoregions (Central Basin and Range and Wasatch and Uinta Mountains) in Utah, USA, to investigate whether bighorns would adjust these life-history characteristics to environmental conditions of the two ecoregions. We also compared timing and synchrony of births for bighorns in their source herd (Antelope Island) with bighorns in an ecologically similar release site (Stansbury Mountains) during 2006 and 2007. Methods We relocated female bighorns to record birthdates of young, and observed groups of collared bighorns to quantify use of elevation by those ungulates. We also calculated the initiation, rate and timing of peak green-up by ecoregion, using the normalised difference vegetation index. Key results We quantified 274 birthdates, and although only separated by 57 km, bighorn populations occupying the Central Basin and Range Mountains gave birth an average of 29 days earlier than did those on the Wasatch and Uinta Mountains, which corresponded with the initiation of vegetation green-up. Additionally, bighorn sheep on the Stansbury Mountains (ecologically similar release site) gave birth at similar times as did bighorns on Antelope Island (source area). Conclusions Populations of bighorn sheep that were reintroduced into adjacent ecoregions adjusted timing of births to environments and green-up of vegetation in restoration areas. Timing and synchrony of births for reintroduced bighorn sheep in an ecologically similar release site were the same as those of their source area. Implications Consideration should be given to the adjustment of timing and synchrony of births when reintroducing bighorns, especially when animals are released into different ecoregions. Also, biologists should select release sites that are ecologically similar to source areas, thereby reducing potential negative effects of animals adjusting timing and synchrony of births to environmental conditions of restoration areas.

scholarly journals Stratigraphy of the Eocene–Oligocene Titus Canyon Formation, Death Valley, California, and Eocene extensional tectonism in the Basin and Range

Geosphere ◽  
2021 ◽  
Author(s):  
Nikolas Midttun ◽  
Nathan A. Niemi ◽  
Bianca Gallina
Keyword(s):  
Detrital Zircon ◽  
Convergence Rates ◽  
Plate Boundary ◽  
Basin And Range ◽  
Late Eocene ◽  
Death Valley ◽  
Central Basin ◽  
Geologic Mapping ◽  
Extensional Basin ◽  
Stress Changes

Geologic mapping, measured sections, and geochronologic data elucidate the tectono-stratigraphic development of the Titus Canyon extensional basin in Death Valley, California, and provide new constraints on the age of the Titus Canyon Formation, one of the earliest syn-extensional deposits in the central Basin and Range. Detrital zircon maximum depositional ages (MDAs) and compiled 40Ar/39Ar ages indicate that the Titus Canyon Formation spans 40(?)–30 Ma, consistent with an inferred Duchesnean age for a unique assemblage of mammalian fossils in the lower part of the formation. The Titus Canyon Formation preserves a shift in depositional environment from fluvial to lacustrine at ca. 35 Ma, which along with a change in detrital zircon provenance may reflect both the onset of local extensional tectonism and climatic changes at the Eocene–Oligocene boundary. Our data establish the Titus Canyon basin as the southernmost basin in a system of late Eocene extensional basins that formed along the axis of the Sevier orogenic belt. The distribution of lacustrine deposits in these Eocene basins defines the extent of a low-relief orogenic plateau (Nevadaplano) that occupied eastern Nevada at least through Eocene time. As such, the age and character of Titus Canyon Formation implies that the Nevadaplano extended into the central Basin and Range, ~200 km farther south than previously recognized. Development of the Titus Canyon extensional basin precedes local Farallon slab removal by ca. 20 Ma, implying that other mechanisms, such as plate boundary stress changes due to decreased convergence rates in Eocene time, are a more likely trigger for early extension in the central Basin and Range.

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