Late-Glacial and Early Holocene Vegetation and Climate Change near Owens Lake, Eastern California

2001 ◽  
Vol 55 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Scott A. Mensing
Keyword(s):  
Climate Change ◽  
Sierra Nevada ◽  
Great Basin ◽  
Younger Dryas ◽  
Late Glacial ◽  
Lake Levels ◽  
Owens Valley ◽  
Desert Shrubs ◽  
Owens Lake ◽  
Lake Record

AbstractPollen and algae from Owens Lake in eastern California provide evidence for a series of climatic oscillations late in the last glaciation. Juniper woodland, which dominated the Owens Valley from 16,200 to 15,500 cal yr B.P., suggests much wetter conditions than today. Although still wetter and cooler than today, the area then became fairly warm and dry, with woodland being replaced by shrubs (mainly sagebrush) from 15,500 to 13,100 cal yr B.P. Next, Chenopodiaceae (shadscale) increased, woody species declined, and lake levels fell—all evidence for a brief (ca. 100–200 yr) drought about 13,000 cal yr B.P. The climate continued to oscillate between wet and dry from 13,000 to 11,000 cal yr B.P. After 11,000 cal yr B.P., low lake levels and the increased dominance of desert shrubs indicate the beginning of warm, dry Holocene conditions. The region's climate was unstable during the Younger Dryas but uncertainities in dating prevent identification of the Younger Dryas interval in the Owens Lake record. Comparison of the Owens Lake record with studies in the Sierra Nevada and Great Basin suggest that the climate was generally wetter between 13,000 and 11,000 cal yr B.P., with warmer summers, although no consistent pattern of climate change emerges.

Sierra Nevada-Great Basin boundary zone: Earthquake hazard related to structure, active tectonic processes, and anomalous patterns of earthquake occurrence

1980 ◽  
Vol 70 (5) ◽  
pp. 1557-1572
Author(s):  
J. D. VanWormer ◽  
Alan S. Ryall
Keyword(s):  
Sierra Nevada ◽  
Great Basin ◽  
Temporal Variations ◽  
Mono Lake ◽  
Local Network ◽  
Low Velocity ◽  
Owens Valley ◽  
Walker Lake ◽  
Fault Plane Solutions ◽  
The North

abstract Precise epicentral determinations based on local network recordings are compared with mapped faults and volcanic features in the western Great Basin. This region is structurally and seismically complex, and seismogenic processes vary within it. In the area north of the rupture zone of the 1872 Owens Valley earthquake, dispersed clusters of epicenters agree with a shatter zone of faults that extend the 1872 breaks to the north and northwest. An area of frequent earthquake swarms east of Mono Lake is characterized by northeast-striking faults and a crustal low-velocity zone; seismicity in this area appears to be related to volcanic processes that produced thick Pliocene basalt flows in the Adobe Hills and minor historic activity in Mono Lake. In the Garfield Hills between Walker Lake and the Excelsior Mountains, there is some clustering of epicenters along a north-trending zone that does not correlate with major Cenozoic structures. In an area west of Walker Lake, low seismicity supports a previous suggestion by Gilbert and Reynolds (1973) that deformation in that area has been primarily by folding and not by faulting. To the north, clusters of earthquakes are observed at both ends of a 70-km-long fault zone that forms the eastern boundary of the Sierra Nevada from Markleeville to Reno. Clusters of events also appear at both ends of the Dog Valley Fault in the Sierra west of Reno, and at Virginia City to the east. Fault-plane solutions for the belt in which major earthquakes have occurred in Nevada during the historic period (from Pleasant Valley in the north to the Excelsior Mountains on the California-Nevada Border) correspond to normaloblique slip and are similar to that found by Romney (1957) for the 1954 Fairview Peak shock. However, mechanisms of recent moderate earthquakes within the SNGBZ are related to right- or left-lateral slip, respectively, on nearly vertical, northwest-, or northeast-striking planes. These mechanisms are explained by a block faulting model of the SNGBZ in which the main fault segments trend north, have normal-oblique slip, and are offset or terminated by northwest-trending strike-slip faults. This is supported by the observation that seismicity during the period of observation has been concentrated at places where major faults terminate or intersect. Anomalous temporal variations, consisting of a general decrease in seismicity in the southern part of the SNGBZ from October 1977 to September 1978, followed by a burst of moderate earthquakes that has continued for more than 18 months, is suggestive of a pattern that several authors have identified as precursory to large earthquakes. The 1977 to 1979 variations are particularly noteworthy because they occurred over the entire SNGBZ, indicating a regional rather than local cause for the observed changes.

The Normal-Faulting 2020 Mw 5.8 Lone Pine, Eastern California, Earthquake Sequence

2020 ◽  
Author(s):  
Egill Hauksson ◽  
Brian Olson ◽  
Alex Grant ◽  
Jennifer R. Andrews ◽  
Angela I. Chung ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Great Basin ◽  
Plate Boundary ◽  
Warning System ◽  
Seismic Energy ◽  
Normal Faulting ◽  
Owens Valley ◽  
Waveform Data ◽  
Earthquake Early Warning System ◽  
Rupture Length

Abstract The 2020 Mw 5.8 Lone Pine earthquake, the largest earthquake on the Owens Valley fault zone, eastern California, since the nineteenth century, ruptured an extensional stepover in that fault. Owens Valley separates two normal-faulting regimes, the western margin of the Great basin and the eastern margin of the Sierra Nevada, forming a complex seismotectonic zone, and a possible nascent plate boundary. Foreshocks began on 22 June 2020; the largest Mw 4.7 foreshock occurred at ∼6  km depth, with primarily normal faulting, followed ∼40  hr later on 24 June 2020 by an Mw 5.8 mainshock at ∼7  km depth. The sequence caused overlapping ruptures across a ∼0.25  km2 area, extended to ∼4  km2, and culminated in an ∼25  km2 aftershock area. The mainshock was predominantly normal faulting, with a strike of 330° (north-northwest), dipping 60°–65° to the east-northeast. Comparison of background seismicity and 2020 Ridgecrest aftershock rates showed that this earthquake was not an aftershock of the Ridgecrest mainshock. The Mw–mB relationship and distribution of ground motions suggest typical rupture speeds. The aftershocks form a north-northwest-trending, north-northeast-dipping, 5 km long distribution, consistent with the rupture length estimated from analysis of regional waveform data. No surface rupture was reported along the 1872 scarps from the 2020 Mw 5.8 mainshock, although, the dipping rupture zone of the Mw 5.8 mainshock projects to the surface in the general area. The mainshock seismic energy triggered rockfalls at high elevations (>3.0  km) in the Sierra Nevada, at distances of 8–20 km, and liquefaction along the western edge of Owens Lake. Because there were ∼30% fewer aftershocks than for an average southern California sequence, the aftershock forecast probabilities were lower than expected. ShakeAlert, the earthquake early warning system, provided first warning within 9.9 s, as well as subsequent updates.

Black Mats, Spring-Fed Streams, and Late-Glacial-Age Recharge in the Southern Great Basin

1998 ◽  
Vol 49 (2) ◽  
pp. 129-148 ◽  
Author(s):  
Jay Quade ◽  
Richard M. Forester ◽  
William L. Pratt ◽  
Claire Carter
Keyword(s):  
Great Basin ◽  
Age Distribution ◽  
Younger Dryas ◽  
Late Glacial ◽  
Land Snails ◽  
Spring Discharge ◽  
Carbon 14 ◽  
Total Absence ◽  
Stratigraphic Record ◽  
Shallow Ponds

Black mats are prominent features of the late Pleistocene and Holocene stratigraphic record in the southern Great Basin. Faunal, geochemical, and sedimentological evidence shows that the black mats formed in several microenvironments related to spring discharge, ranging from wet meadows to shallow ponds. Small land snails such as Gastrocopta tappaniana and Vertigo berryi are the most common mollusk taxa present. Semiaquatic and aquatic taxa are less abundant and include Catinellids, Fossaria parva, Gyraulus parvus, and others living today in and around perennial seeps and ponds. The ostracodes Cypridopsis okeechobi and Scottia tumida, typical of seeps and low-discharge springs today, as well as other taxa typical of springs and wetlands, are common in the black mats. Several new species that lived in the saturated subsurface also are present, but lacustrine ostracodes are absent. The δ13C values of organic matter in the black mats range from −12 to −26‰, reflecting contributions of tissue from both C3 (sedges, most shrubs and trees) and C4 (saltbush, saltgrass) plants. Carbon-14 dates on the humate fraction of 55 black mats fall between 11,800 to 6300 and 2300 14C yr B.P. to modern. The total absence of mats in our sample between 6300 and 2300 14C yr B.P. likely reflects increased aridity associated with the mid-Holocene Altithermal. The oldest black mats date to 11,800–11,600 14C yr B.P., and the peak in the 14C black mat distribution falls at ∼10,000 14C yr B.P. As the formation of black mats is spring related, their abundance reflects refilling of valley aquifers starting no later than 11,800 and peaking after 11,000 14C yr B.P. Reactivation of spring-fed channels shortly before 11,200 14C yr B.P. is also apparent in the stratigraphic records from the Las Vegas and Pahrump Valleys. This age distribution suggests that black mats and related spring-fed channels in part may have formed in response to Younger Dryas (YD)-age recharge in the region. However, the inception of black mat formation precedes that of the YD by at least 40014C yr, and hydrological change is gradual, not rapid.

Evidence of temperature depression and hydrological variations in the eastern Sierra Nevada during the Younger Dryas Stade

2008 ◽  
Vol 70 (2) ◽  
pp. 131-140 ◽  
Author(s):  
Glen M. MacDonald ◽  
Katrina A. Moser ◽  
Amy M. Bloom ◽  
David F. Porinchu ◽  
Aaron P. Potito ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Great Basin ◽  
North Atlantic ◽  
Younger Dryas ◽  
East Central ◽  
The North ◽  
Dry Conditions ◽  
Maximum Temperatures ◽  
Temperature Depression ◽  
The North Pacific

AbstractSediment records from two lakes in the east-central Sierra Nevada, California, provide evidence of cooling and hydrological shifts during the Younger Dryas stade (YD; ~ 12,900–11,500 cal yr BP). A chironomid transfer function suggests that lake-water temperatures were depressed by 2°C to 4°C relative to maximum temperatures during the preceding Bølling–Allerød interstade (BA; ~ 14,500–12,900 cal yr BP). Diatom and stable isotope records suggest dry conditions during the latter part of the BA interstade and development of relatively moist conditions during the initiation of the YD stade, with a reversion to drier conditions later in the YD. These paleohydrological inferences correlate with similar timed changes detected in the adjacent Great Basin. Vegetation response during the YD stade includes the development of more open and xeric vegetation toward the end of the YD. The new records support linkages between the North Atlantic, the North Pacific, and widespread YD cooling in western North America, but they also suggest complex hydrological influences. Shifting hydrological conditions and relatively muted vegetation changes may explain the previous lack of evidence for the YD stade in the Sierra Nevada and the discordance in some paleohydrological and glacial records of the YD stade from the western United States.

A 740,000-yr-long Mohawk Lake record, Mohawk Valley, northeastern California, USA

2019 ◽  
Author(s):  
Joanna R. Redwine ◽  
Kenneth D. Adams
Keyword(s):  
Sierra Nevada ◽  
Lake Levels ◽  
Valley Bottom ◽  
Closed Basin ◽  
Mohawk Valley ◽  
Ice Cap ◽  
Lake History ◽  
Middle And Late Pleistocene ◽  
Tephra Beds ◽  
Lake Record

ABSTRACT Mohawk Valley lies in northeastern California on the margin of the northernmost Sierra Nevada and was occupied by Mohawk Lake during much of the middle and late Pleistocene. Throughout that time, the Sierra Nevada ice cap repeatedly extended northward into Mohawk Lake, and ice-contact deltaic sediments were deposited along the valley margins and in the valley bottom. Nearly 200 m of lacustrine and deltaic sediments are now well exposed along streams draining the Sierra Nevada. Tephra beds deposited within the deltaic sediments allow correlation of stratigraphic sections around the valley margin and, together with geomorphic evidence of former lake levels, permit interpretation of a Mohawk Lake history as far back as 740 ka. Mohawk Valley changed from a through-flowing fluvial setting to an intermittent closed basin sometime before 740 ka. After this change occurred, relatively small lakes intermittently formed in Mohawk Valley until ca. 600 ka, when the lake dramatically deepened. Mohawk Lake fluctuated in size over the next ~400,000 yr and increased in size to its highest levels after ca. 200 ka, possibly due to drainage integration with the upstream Lake Beckwourth. After this time, Mohawk Lake spilled over its westward sill, incrementally eroding and lowering lake levels until Mohawk Lake was emptied by ca. 7 ka.

Desert wetlands record hydrologic variability within the Younger Dryas chronozone, Mojave Desert, USA

2018 ◽  
Vol 91 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Jeffrey S. Pigati ◽  
Kathleen B. Springer ◽  
Jeffrey S. Honke
Keyword(s):  
Climate Change ◽  
Great Basin ◽  
Mojave Desert ◽  
Late Quaternary ◽  
Younger Dryas ◽  
Human Society ◽  
Wetland Ecosystems ◽  
Hydrologic Variability ◽  
Dry Conditions ◽  
Wet And Dry Cycles

AbstractOne of the enduring questions in the field of paleohydrology is how quickly desert wetland ecosystems responded to past episodes of abrupt climate change. Recent investigations in the Las Vegas Valley of southern Nevada have revealed that wetlands expanded and contracted on millennial and sub-millennial timescales in response to changes in climate during the late Quaternary. Here, we evaluate geologic evidence from multiple localities in the Mojave Desert and southern Great Basin that suggests the response of wetland systems to climate change is even faster, occurring at centennial, and possibly decadal, timescales. Paleowetland deposits at Dove Springs Wash, Mesquite Springs, and Little Dixie Wash, California, contain evidence of multiple wet and dry cycles in the form of organic-rich black mats, representing periods of past groundwater discharge and wet conditions, interbedded with colluvial, alluvial, and aeolian sediments, each representing dry conditions. Many of these wet-dry cycles date to within the Younger Dryas (YD) chronozone (12.9–11.7 ka), marking the first timeintra-YD hydrologic variability has been documented in paleowetland deposits. Our results illustrate that desert wetland ecosystems are exceptionally sensitive to climate change and respond to climatic perturbations on timescales that are relevant to human society.

Late-Glacial climatic changes in Eastern France (Lake Lautrey) from pollen, lake-levels, and chironomids

2005 ◽  
Vol 64 (2) ◽  
pp. 197-211 ◽  
Author(s):  
O. Peyron ◽  
C. Bégeot ◽  
S. Brewer ◽  
O. Heiri ◽  
M. Magny ◽  
...  
Keyword(s):  
Younger Dryas ◽  
Late Glacial ◽  
High Temporal Resolution ◽  
Lake Levels ◽  
Late Glacial Period ◽  
Climate Reconstructions ◽  
Quantitative Estimates ◽  
Abrupt Changes ◽  
Cold Events ◽  
Climate Signals

AbstractHigh-temporal resolution analyses of pollen, chironomid, and lake-level records from Lake Lautrey provide multi-proxy, quantitative estimates of climatic change during the Late-Glacial period in eastern France. Past temperature and moisture parameters were estimated using modern analogues and ‘plant functional types’ transfer-function methods for three pollen records obtained from different localities within the paleolake basin. The comparison of these methods shows that they provide generally similar climate signals, with the exception of the Bölling. Comparison of pollen- and chironomid-based temperature of the warmest month reconstructions generally agree, except during the Bölling. Major abrupt changes associated with the Oldest Dryas/Bölling, Alleröd/Younger Dryas, and the Younger Dryas/Preboreal transitions were quantified as well as other minor fluctuations related to the cold events (e.g., Preboreal oscillation). The temperature of the warmest month increased by ∼5°C at the start of Bölling, and by 1.5°�"3°C at the onset of the Holocene, while it fell by ca. 3° to 4°C at the beginning of Younger Dryas. The comparative analysis of the results based on the three Lautrey cores have highlighted significant differences in the climate reconstructions related to the location of each core, underlining the caution that is needed when studying single cores not taken from deepest part of lake basins.

Water and power

2013 ◽  
Vol 3 (3) ◽  
pp. 60-67
Author(s):  
Ron Nichols
Keyword(s):  
Climate Change ◽  
Los Angeles ◽  
Owens Valley ◽  
Owens Lake ◽  
The Past

An interview with Ron Nichols, director of the Los Angeles Department of Water and Power surveys the past, present, and future of the Los Angeles Aqueduct, the department's relationship with Owens Valley, restoration of Owens Lake, the role of the department and its unions in city politics, climate change and the challenges ahead.

Climatic/Hydrologic Oscillations since 155,000 yr B.P. at Owens Lake, California, Reflected in Abundance and Stable Isotope Composition of Sediment Carbonate

1997 ◽  
Vol 48 (1) ◽  
pp. 58-68 ◽  
Author(s):  
Kirsten M. Menking ◽  
James L. Bischoff ◽  
John A. Fitzpatrick ◽  
James W. Burdette ◽  
Robert O. Rye
Keyword(s):  
Climate Change ◽  
Grain Size ◽  
Sierra Nevada ◽  
Isotope Composition ◽  
Carbonate Content ◽  
Stable Isotope Composition ◽  
Sediment Grain Size ◽  
First Order ◽  
Owens Lake ◽  
Isotopic Records

Sediment grain size, carbonate content, and stable isotopes in 70-cm-long (∼1500-yr) channel samples from Owens Lake core OL-92 record many oscillations representing climate change in the eastern Sierra Nevada region since 155,000 yr B.P. To first order, the records match well the marine δ18O record. At Owens Lake, however, the last interglaciation appears to span the entire period from 120,000 to 50,000 yr B.P., according to our chronology, and was punctuated by numerous short periods of wetter conditions during an otherwise dry climate. Sediment proxies reveal that the apparent timing of glacial–interglacial transitions, notably the penultimate one, is proxy-dependent. In the grain-size and carbonate-content records this transition is abrupt and occurs at ∼120,000 yr B.P. In contrast, in the isotopic records the transition is gradual and occurs between 145,000 and 120,000 yr B.P. Differences in timing of the transition are attributed to variable responses by proxies to climate change.

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