A5049678616- Geology and Paleoclimatology Research
- Cryospheric studies and observations
- Geological formations and processes
- Methane Hydrates and Related Phenomena
- Climate change and permafrost
- Pleistocene-Era Hominins and Archaeology
- Environmental and Cultural Studies in Latin America and Beyond
- Geomagnetism and Paleomagnetism Studies
- earthquake and tectonic studies
- Geochemistry and Geologic Mapping
- Archaeology and Natural History
- Geological Studies and Exploration
- Geological and Geochemical Analysis
- Marine and environmental studies
- Tree-ring climate responses
- Geological and Geophysical Studies
- Landslides and related hazards
- Geological and Tectonic Studies in Latin America
- Hydrocarbon exploration and reservoir analysis
- Isotope Analysis in Ecology
- Historical and Archaeological Studies
- Archaeological and Geological Studies
- Botany and Geology in Latin America and Caribbean
- Groundwater and Isotope Geochemistry
- Coastal and Marine Dynamics
Occidental College
2015-2024
University of Pittsburgh
2014-2022
Planetary Science Institute
2016
University of Colorado Boulder
2011-2015
Institute of Arctic and Alpine Research
2011-2015
University of Iceland
2011-2015
University of Colorado System
2012
Northern Hemisphere summer temperatures over the past 8000 years have been paced by slow decrease in insolation resulting from precession of equinoxes. However, causes superposed century‐scale cold anomalies, which Little Ice Age (LIA) is most extreme, remain debated, largely because natural forcings are either weak or, case volcanism, short lived. Here we present precisely dated records ice‐cap growth Arctic Canada and Iceland showing that LIA ice began abruptly between 1275 1300 AD,...
Abstract. Strong similarities in Holocene climate reconstructions derived from multiple proxies (BSi, TOC – total organic carbon, δ13C, C∕N, MS magnetic susceptibility, δ15N) preserved sediments both glacial and non-glacial lakes across Iceland indicate a relatively warm early to mid 10 6 ka, overprinted with cold excursions presumably related meltwater impact on North Atlantic circulation until 7.9 ka. Sediment catchments indicates their were ice-free during this interval. Statistical...
Abstract Our understanding of the climatic teleconnections that drove ice-age cycles has been limited by a paucity well-dated tropical records glaciation span several glacial–interglacial intervals. Glacial deposits offer discrete snapshots glacier extent but cannot provide continuous required for detailed interhemispheric comparisons. By contrast, lakes located within glaciated catchments can archives upstream glacial activity, few such extend beyond last cycle. Here piston core from Lake...
Abstract Global climate during the Holocene was relatively stable compared to late Pleistocene. However, evidence from lacustrine records in South America suggests that tropical latitudes experienced significant water balance variability Holocene, rather than quiescence. For example, a tight coupling between insolation and carbonate δ 18 O central Andean lakes (e.g., Lakes Junín, Pumacocha) suggest is tied directly American summer monsoon (SASM) strength. lake also incorporate information...
Geological evidence indicates that glaciers in the western United States fluctuated response to Holocene changes temperature and precipitation. However, because moraine chronologies are characteristically discontinuous, glacier fluctuations their climatic drivers remain ambiguous, future uncertain. Here, we construct a continuous 10-thousand-year (ka) record of activity Teton Range, Wyoming, using glacial environmental indicators alpine lake sediments. We show persisted some form through...
Abstract Geologic records of past earthquakes are rare but critical for identifying long‐term patterns in fault behavior and assessing modern earthquake hazards. We present a continuous 14,000‐year paleoearthquake reconstruction using precisely dated lacustrine sediments landslide deposits from lake basin positioned directly on the Teton normal fault, which cuts across Grand National Park, WY, is among most hazardous intraplate faults western United States. show that beginning immediately...
Research Article| February 01, 2015 Precise chronology of Little Ice Age expansion and repetitive surges Langjökull, central Iceland Darren J. Larsen; Larsen 1Institute Earth Sciences, University Iceland, Reykjavík 101, Iceland2Institute Arctic Alpine Research, Department Geological Colorado, Boulder, Colorado 80309, USA *Current address: Geology Planetary Science, Pittsburgh, Pennsylvania 15260, USA. Search for other works by this author on: GSW Google Scholar Áslaug Geirsdóttir;...
Lakes in seismically active regions preserve valuable sedimentary archives of paleoseismic activity within their catchment and beyond. A series glacially-excavated lakes positioned directly along the surface trace Teton normal fault at base Range, WY, are ideally situated to record past since formation approximately 15,000 years ago. Here, we focus on sediment fill contained Jenny Lake (5 km 2 ; 73 m max depth) located bottom Cascade Canyon, central Tetons, where postglacial slip rates...
Hvitarvatn is a proglacial lake adjacent to Langjokull, the second largest ice cap in Iceland. The 422 m a.s.l. and 36 km2 with maximum depth of 85 (Fig. 1). Langjokull feeds two outlet glaciers, Suðurjokull Norðurjokull, which both terminated during Little Ice Age (LIA; AD 1300–1900). LIA extent glaciers clearly defined by moraines visible on land high-frequency multibeam sonar bathymetric images bottom (Geirsdottir et al. 2008). bathymetry, chirp profiles numerous sediment cores contain...
Abstract Beaver-based restoration is emerging as a cost-effective conservation and climate adaptation strategy, but efforts are constrained by limited knowledge of pre-colonial beaver distribution their long-term ecosystem impacts. Here, we apply sedimentary ancient DNA (sedaDNA) techniques to investigate the history occupancy at three lakes in Grand Teton National Park, Wyoming over last ∼10 ka, well interactions with local plant community. We documented dynamic presence two sub-alpine...