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Jeff Pigati

I grew up in central Illinois and didn't travel much as a child. In fact, I never even saw a mountain in person until I attended summer field camp in Red Lodge, Montana at the age of 20 (no joke!). Needless to say, I was hooked immediately and have spent the last couple of decades making up for lost time.

I am currently doing research all over the southwestern U.S., the Atacama Desert of northern Chile, the Middle East (Jordan), and the California Channel Islands. My work focuses primarily on using geologic deposits associated with springs and wetlands to understand the hydrologic response of small desert watersheds to past episodes of abrupt climate change. I also develop and test new and innovative methods for dating various materials by radiocarbon, including gastropod shells, old charcoal, tufa, and concentrated organic matter.

 

 

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scientists near Saratoga Springs, Death Valley

Quaternary Hydroclimate Records of Spring Ecosystems

Desert springs and wetlands are among the most biologically productive, diverse, and fragile ecosystems on Earth. They are home to thousands of rare, endemic, and endangered plants and animals and reflect the availability and health of emergent groundwater. Despite the ecological importance of these wetlands, our knowledge of how they might respond to predicted future climate change is limited...
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Climate Research and Development Program, Geosciences and Environmental Change Science Center
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Quaternary Hydroclimate Records of Spring Ecosystems

Desert springs and wetlands are among the most biologically productive, diverse, and fragile ecosystems on Earth. They are home to thousands of rare, endemic, and endangered plants and animals and reflect the availability and health of emergent groundwater. Despite the ecological importance of these wetlands, our knowledge of how they might respond to predicted future climate change is limited...
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Coral reef and overlying marine deposits a few meters above sea level, south of Kaena Point, Hawaii

Geologic Records of High Sea Levels

This project studies past high sea levels on coastlines that preserve fossil coral reefs or marine terraces. We ascertain the magnitudes of sea-level high stands by field mapping, stratigraphic measurements, and precise elevation measurements. Geochronology is accomplished by radiocarbon dating of mollusks (for Holocene-to-last-glacial deposits), uranium-series dating of corals (for high-sea...
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Climate Research and Development Program, Geosciences and Environmental Change Science Center
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Geologic Records of High Sea Levels

This project studies past high sea levels on coastlines that preserve fossil coral reefs or marine terraces. We ascertain the magnitudes of sea-level high stands by field mapping, stratigraphic measurements, and precise elevation measurements. Geochronology is accomplished by radiocarbon dating of mollusks (for Holocene-to-last-glacial deposits), uranium-series dating of corals (for high-sea...
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Desert wetland at Point of Rocks Spring

Paleohydrology of Desert Wetlands

Springs and wetlands are among the most highly threatened ecosystems on Earth. Although geographically limited, they support more than 20% of all the threatened and endangered species in the United States. Scientists from the U.S. Geological Survey are examining the rock record to determine how springs and wetlands responded to abrupt climate change during prehistoric times and the recent geologic...
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Climate Research and Development Program, Geosciences and Environmental Change Science Center
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Paleohydrology of Desert Wetlands

Springs and wetlands are among the most highly threatened ecosystems on Earth. Although geographically limited, they support more than 20% of all the threatened and endangered species in the United States. Scientists from the U.S. Geological Survey are examining the rock record to determine how springs and wetlands responded to abrupt climate change during prehistoric times and the recent geologic...
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Data release for Seasonality of precipitation in the southwestern United States during the late Pleistocene inferred from stable isotopes in herbivore tooth enamel

The late Pleistocene was a climatically dynamic period, with abrupt shifts between cool-wet and warm-dry conditions. Increased effective precipitation supported large pluvial lakes and long-lived spring ecosystems in valleys and basins throughout the western and southwestern U.S., but the source and seasonality of the precipitation are debated. Here we present stable carbon and oxygen isotope data
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Geosciences and Environmental Change Science Center

Data release for Hydroclimate response of spring ecosystems to a two-stage Younger Dryas event in western North America

The Younger Dryas (YD) climate event is the preeminent example of abrupt climate change in the recent geologic past. Climate conditions during the YD were spatially complex, and high-resolution sediment cores in the North Atlantic, western Europe, and East Asia have revealed it unfolded in two distinct stages, including an initial stable climatic period between ~12.9 and 12.2 ka associated with a
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Geosciences and Environmental Change Science Center

Data release for Oxygen isotopes of land snail shells in high latitude regions

The present study investigates the environmental significance of the oxygen isotopic composition of several modern land snail species collected along two north-to-south transects in Alaska and Scandinavia at latitudes between 60 and 70 degrees N. We tested the hypothesis that land snail shell Delta18O values primarily track precipitation Delta18O. The results show that shell Delta18O values from S
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Data release for Evidence of humans in North America during the Last Glacial Maximum

Archaeologists and researchers in allied fields have long sought to understand human colonization of North America. Questions remain about when and how people migrated, where they originated, and how their arrival affected the established fauna and landscape. Here, we present evidence from excavated surfaces in White Sands National Park (New Mexico, United States), where multiple in situ human foo
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Radiocarbon dating of an alluvial deposit with associated faunal remains

We assessed a construction site in the northern Las Vegas Valley that was initially reported as an "ice age" deposit. Alluvial deposits exposed at the site were inset into the Las Vegas Formation and contained semi-articulated Equus remains. Calibrated radiocarbon dates on two different materials associated with the remains centered on 1957, thus rendering the horse bones as modern.
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Data release for Oxygen isotopes in terrestrial gastropod shells track Quaternary climate change in the American Southwest

Recent studies have shown the oxygen isotopic composition (delta18O) of modern terrestrial gastropod shells is determined largely by the delta18O of precipitation. This implies that fossil shells could be used to reconstruct the delta18O of paleo-precipitation as long as the hydrologic pathways of the local watershed and the shell isotope systematics are well understood. In this study, we measured
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Data release for Climatically driven displacement on the Eglington fault, Las Vegas, Nevada, USA

The Eglington fault is one of several intrabasinal faults in the Las Vegas Valley, Nevada, USA, and is the only one recognized as a source for significant earthquakes. Its broad warp displaces Late Pleistocene spring deposits of the Las Vegas Formation, which record hydrologic fluctuations that occurred in response to millennial- and submillennial-scale climate oscillations throughout the late Qua
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Geosciences and Environmental Change Science Center
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Seasonality of precipitation in the southwestern United States during the late Pleistocene inferred from stable isotopes in herbivore tooth enamel

The late Pleistocene was a climatically dynamic period, with abrupt shifts between cool-wet and warm-dry conditions. Increased effective precipitation supported large pluvial lakes and long-lived spring ecosystems in valleys and basins throughout the western and southwestern U.S., but the source and seasonality of the increased precipitation are debated. Increases in the proportions of C4/(C4+ C3)
By
Geosciences and Environmental Change Science Center

Hydroclimate response of spring ecosystems to a two-stage Younger Dryas event in western North America

The Younger Dryas (YD) climate event is the preeminent example of abrupt climate change in the recent geologic past. Climate conditions during the YD were spatially complex, and high-resolution sediment cores in the North Atlantic, western Europe, and East Asia have revealed it unfolded in two distinct stages, including an initial stable climatic period between ~ 12.9 and 12.2 ka associated with a
By
Climate Research and Development Program, Geosciences and Environmental Change Science Center

Reply to “Evidence for humans at White Sands National Park during the Last Glacial Maximum could actually be for Clovis people ~13,000 years ago” by C. Vance Haynes, Jr.

Bennett et al. (2021, Science 373, 1528–1531) reported that ancient human footprints discovered in White Sands National Park, New Mexico date to between ∼23,000 and 21,000 years ago. Haynes (2022, PaleoAmerica, this issue) proposes two alternate hypotheses to explain the antiquity of the footprints. One is that they were made by humans crossing over older sediments sometime during the Holocene. Th
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Oxygen isotopes of land snail shells in high latitude regions

The present study investigates the environmental significance of the oxygen isotopic composition of several modern land snail species collected along two north-to-south transects in Alaska and Scandinavia at latitudes between 60 and 70 °N. We tested the hypothesis that land snail shell δ18O values primarily track precipitation δ18O. The results show that shell δ18O values from Scandinavia were ∼5.
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Response to comment on “Evidence of humans in North America during the Last Glacial Maximum”

Madsen et al. question the reliability of calibrated radiocarbon ages associated with human footprints discovered recently in White Sands National Park, New Mexico, USA. On the basis of the geologic, hydrologic, stratigraphic, and chronologic evidence, we maintain that the ages are robust and conclude that the footprints date to between ~23,000 and 21,000 years ago.Madsen et al. (1) question the v
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Evidence of glacial activity during MIS 4 in the Rocky Mountains, Colorado, USA

The Ziegler Reservoir fossil site near Snowmass Village, Colorado, provides a rare opportunity to examine environmental conditions in the Rocky Mountains during marine isotope stage (MIS) 4 (71–57 ka). Although recognized as a global-scale cold event, MIS 4 is typically absent from Rocky Mountain glacial chronologies because the geologic evidence was covered or destroyed during the subsequent, and
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Evidence for humans in North America during the Last Glacial Maximum

Archaeologists and researchers in allied fields have long sought to understand human colonization of North America. When, how, and from where did people migrate, and what were the consequences of their arrival for the established fauna and landscape are enduring questions. Here, we present evidence from excavated surfaces of in situ human footprints from White Sands National Park (New Mexico, USA)
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Aeolian sediments in paleowetland deposits of the Las Vegas Formation

The Las Vegas Formation (LVF) is a well-characterized sequence of groundwater discharge (GWD) deposits exposed in and around the Las Vegas Valley in southern Nevada. Nearly monolithologic bedrock surrounds the valley, which provides an excellent opportunity to test the hypothesis that GWD deposits include an aeolian component. Mineralogical data indicate that the LVF sediments are dominated by car
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Oxygen isotopes in terrestrial gastropod shells track Quaternary climate change in the American Southwest

Recent studies have shown the oxygen isotopic composition (δ18O) of modern terrestrial gastropod shells is determined largely by the δ18O of precipitation. This implies that fossil shells could be used to reconstruct the δ18O of paleo-precipitation as long as the isotopic system, including the hydrologic pathways of the local watershed and the gastropod systematics, is well understood. In this stu
By
Climate Research and Development Program, Geosciences and Environmental Change Science Center

Climatically driven displacement on the Eglington fault, Las Vegas, Nevada

The Eglington fault is one of several intrabasinal faults in the Las Vegas Valley, Nevada and is the only one recognized as a source for significant earthquakes. Its broad warp displaces late Pleistocene paleo-spring deposits of the Las Vegas Formation, which record hydrologic fluctuations that occurred in response to millennial and submillennial-scale climate oscillations throughout the late Quat
By
Climate Research and Development Program, Geosciences and Environmental Change Science Center

Fluvial sedimentary history of Arlington Canyon, Channel Islands National Park, California

Arlington Canyon, in the northwest part of Santa Rosa Island, Channel Islands National Park, California, has been the setting for important scientific discoveries over the past half century, including the oldest human remains in North America, several vertebrate fossil sites, and purported evidence of a catastrophic extinction event at the end of the Pleistocene. The canyon is filled with alluvial
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Late Quaternary paleohydrology of desert wetlands and pluvial lakes in the Soda Lake basin, central Mojave Desert, California (USA)

Sediment cores taken near extant springs along the western margin of Soda Lake playa, as well as from the playa center, reveal dramatic hydrologic changes that occurred in the central Mojave Desert during the late Quaternary. Results of stratigraphic, chronologic, physical, chemical, and microfossil analyses of seven cores, ranging in length from 5 to 23 m, help refine the timing and character of
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Climate Research and Development Program, Geosciences and Environmental Change Science Center

Non-USGS Publications**

Pigati, J.S. Miller, D.M., 2008, Late Pleistocene wetland deposits at Valley Wells, eastern Mojave Desert, California: initial results. In Trough to trough: the Colorado River and the Salton Sea - 2008 Desert Symposium Field Guide and Proceedings, R.E. Reynolds (Ed.), California State University, Desert Studies Consortium, and LSA Associates, Inc., 138-142.
Pigati, J.S., Quade, J., Wilson, J., Jull, A.J.T., Lifton, N.A., 2007, Development of low-background vacuum extraction and graphitization systems for 14C dating of old (40-60 ka) samples. Quaternary International 166, 4-14.
Felton, A.A., Russell, J.M., Cohen, A.S., Baker, M.E., Chesley, J., Lezzar, K.E., McGlue, M.M., Pigati, J.S., Quade, J., Stager, J.C., 2007, Paleolimnological evidence for the onset and termination of glacial aridity from Lake Tanganyika, East Tropical Africa. Palaeogeography, Palaeoclimatology, Palaeoecology 252, 405-423.
Shanahan, T.S., Overpeck, J.T., Beck, J.W., Wheeler, C.W., Pigati, J.S., Talbot, M.R., Scholz, C.A., Peck, J., King, J.W., 2006, Paleoclimatic variations in West Africa from a record of late Pleistocene and Holocene lake level stands of Lake Bosumtwi, Ghana. Palaeogeography, Palaeoclimatology, Palaeoecology 242 (3-4), 287-302.
Shanahan, T.M., Pigati, J.S., Dettman, D.L., Quade, J., 2005, Isotopic variability in the aragonite shells of freshwater gastropods living in springs with nearly constant temperature and isotopic composition. Geochimica et Cosmochimica Acta 69 (16), 3949-3966.
Pigati, J.S., Lifton, N.A., 2004, Geomagnetic effects on time-integrated cosmogenic nuclide production with emphasis on in-situ 14C and 10Be. Earth and Planetary Science Letters 226, 193-205. (Elsevier Top 50 Most Cited Papers 2004-2007 Award).
Pigati, J.S., Quade, J., Shanahan, T.M., Haynes, C.V. Jr., 2004, Radiocarbon dating of minute gastropods and new constraints on the timing of late Quaternary spring-discharge deposits in southern Arizona, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 204 (1-2), 33-45.
Rech, J.A., Pigati, J.S., Quade, J., Betancourt, J.L., 2003, Re-evaluation of mid-Holocene wetland deposits at Quebrada Puripica, northern Chile. Palaeogeography, Palaeoclimatology, Palaeoecology 194, 207-222.
Pigati, J.S., 2002, On correcting 14C ages of gastropod shell carbonate for fractionation. Radiocarbon 44(3), 755-760.
Stiner, M.C., Achyuthan, H., Arsebuk, G., Howell, F.C., Josephson, S.C., Juell, K.E., Pigati, J.S., Quade, J., 1998, Reconstructing cave bear paleoecology from skeletons: A cross-disciplinary study of middle-Pleistocene bears from Yarimburgaz Cave, Turkey. Paleobiology 24, 74-96.

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

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Hydrologic response to climate change in the Las Vegas Valley

This article is part of the Spring 2016 issue of the Earth Science Matters Newsletter. 

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Paleowetland deposits showing black mat
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