Pervasive Desiccation of North American Lakes During the Late Quaternary

Shuman, Bryan N.

doi:10.1029/2019gl086412

Cited by 16 publications

(14 citation statements)

References 57 publications

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“…The dominant vegetation is dryland scrub and the soils are mostly relatively saline and alkaline. During most of the Pleistocene, the region was much wetter and cooler than today, with the transition to arid and semiarid conditions similar to the present climate taking place from about 12 to 6 ka BP (BP: before present, referring to the year 2000 CE), involving highly variable conditions [65][66][67]. An extensive drought period occurred between about 5000 and 4000 BP [68, and references therein].…”

Section: Study Region Climate and Historymentioning

confidence: 99%

Geochemical studies on rock varnish and petroglyphs in the Owens and Rose Valleys, California

Alamri

Andreae

Garfinkel³

et al. 2020

PLoS ONE

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We investigated rock varnish, a thin, manganese- and iron-rich, dark surface crust, on basaltic lava flows and petroglyphs in the Owens and Rose Valleys (California) by portable X-ray fluorescence (pXRF) and femtosecond laser-ablation inductively-coupled-plasma mass spectrometry (fs-LA-ICPMS). The major element composition of the varnish was consistent with a mixture of Mn-Fe oxyhydroxides and clay minerals. As expected, it contained elevated concentrations of elements that are typically enriched in rock varnish, e.g., Mn, Pb, Ba, Ce, and Co, but also showed unusually high enrichments in U, Cu, and Th. The rare earth and yttrium (REY) enrichment pattern revealed a very strong positive cerium (Ce) anomaly and distinct negative europium (Eu) and Y anomalies. The light rare earth elements (REE) were much more strongly enriched than the heavy REY. These enrichment patterns are consistent with a formation mechanism by leaching of Mn and trace elements from aeolian dust, reprecipitation of Mn and Fe as oxyhydroxides, and scavenging of trace elements by these oxyhydroxides. We inferred accumulation rates of Mn and Fe in the varnish from their areal densities measured by pXRF and the known ages of some of the lava flow surfaces. The areal densities of Mn and Fe, as well as their accumulation rates, were comparable to our previous results from the desert of Saudi Arabia. There was a moderate dependence of the Mn areal density on the inclination of the rock surfaces, but no relationship to its cardinal orientation. We attempted to use the degree of varnish regrowth on the rock art surfaces as an estimate of their age. While an absolute dating of the petroglyphs was not possible because of the lack of suitable calibration surfaces and a considerable amount of variability, the measured degree of varnish regrowth on the various petroglyphs was consistent with chronologies based on archeological and other archaeometric techniques. In particular, our results suggest that rock art creation in the study area continued over an extended period of time, possibly starting around the Pleistocene/Holocene transition and extending into the last few centuries.

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Section: Study Region Climate and Historymentioning

confidence: 99%

Geochemical studies on rock varnish and petroglyphs in the Owens and Rose Valleys, California

Alamri

Andreae

Garfinkel³

et al. 2020

PLoS ONE

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“…However, the timing of peak sedimentation and therefore organic carbon burial would have varied widely among different closed basins, due to regional differences in climate, vegetation and lake evolution since the LGM. Pluvial Great Basin during the LGM and Green Sahara during the Holocene are prime examples of this difference in lake evolution [ 14 , 27 , 42 , 44 ]. Another source of uncertainty in lake organic carbon sink estimation is that many closed-basin lakes, active since the LGM, have dried out in recent times, exposing organic carbon in lake sediments to oxidizing atmosphere conditions.…”

Section: Resultsmentioning

confidence: 99%

Changes of lake organic carbon sinks from closed basins since the Last Glacial Maximum and quantitative evaluation of human impacts

Liu

Zhang

et al. 2021

Carbon Balance Manage

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Background Closed basins occupy 21% of the world’s land area and can substantially affect global carbon budgets. Conventional understanding suggests that the terminal areas of closed basins collect water and carbon from throughout the entire basin, and changes in lake organic carbon sinks are indicative of basin-wide organic carbon storages. However, this hypothesis lacks regional and global validation. Here, we first validate the depositional process of organic carbon in a typical closed-basin region of northwest China using organic geochemical proxies of both soil and lake sediments. Then we estimate the organic carbon sinks and human impacts in extant closed-basin lakes since the Last Glacial Maximum (LGM). Results Results show that 80.56 Pg organic carbon is stored in extant closed-basin lakes mainly found in the northern mid-latitudes. Carbon accumulation rates vary from 17.54 g C m−2 yr−1 during modern times, 6.36 g C m−2 yr−1 during the mid-Holocene and 2.25 g C m−2 yr−1 during the LGM. Then, we evaluated the influence by human activities during the late Holocene (in the past three thousand years). The ratio of human impacts on lake organic carbon storage in above closed basins is estimated to be 22.79%, and human-induced soil organic carbon emissions in the past three thousand years amounted to 207 Pg. Conclusions While the magnitude of carbon storage is not comparable to those in peatland, vegetation and soil, lake organic carbon sinks from closed basins are significant to long-term terrestrial carbon budget and contain information of climate change and human impact from the whole basins. These observations improve our understanding of carbon sinks in closed basins at various time scales, and provide a basis for the future mitigation policies to global climate change.

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“…In this study, we compiled the continuous reconstructed lake-level records in global closed basin, as sedimentary records of lake-level fluctuations have long provided unambiguous evidence of past hydrologic changes (Liefert and Shuman, 2020). The reconstructed lake level must cover at least one cycle of cold and warm events (MH-LGM, B/A-YD, or MCA-LIA).…”

Section: Methodsmentioning

confidence: 99%

Timescale-dependent responses of hydrological changes from global closed basins since the last glacial maximum

Zhang

Qin

et al. 2021

Progress in Physical Geography: Earth and Environment

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Water shortage has plagued the social development and human well-being of global closed basins. However, the hydroclimate research on different time scales in these regions remains inadequate at a global scale. In this paper, the hydrological responses from global closed basins to millennial-scale and centennial-scale cold/warm events since the Last Glacial Maximum were explored. Closed-basin lake records indicate that the westerlies-dominated closed basins are generally wetter during cold events than the corresponding warm ones on the millennial and centennial scales. In contrast, the monsoon-influenced closed basins prevail wetter climates during warm events. According to the hydroclimate simulations, precipitation seasonality plays a significant role in causing above spatial–temporal patterns. There is more winter rainfall in westerlies-dominated closed basins during cold events in the Last Glacial Maximum and Little Ice Age and more summer rainfall in monsoon-influenced closed basins during warm events in the mid-Holocene and Medieval Climate Anomaly. Under modern and future global warming, the hydroclimate changes in global closed basins show more regional differentiation, resulting in wetter mid-latitude Asian and low-latitude African closed basins but drier southwest North American and Australian closed basins.

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Pervasive Desiccation of North American Lakes During the Late Quaternary

Cited by 16 publications

References 57 publications

Geochemical studies on rock varnish and petroglyphs in the Owens and Rose Valleys, California

Geochemical studies on rock varnish and petroglyphs in the Owens and Rose Valleys, California

Changes of lake organic carbon sinks from closed basins since the Last Glacial Maximum and quantitative evaluation of human impacts

Timescale-dependent responses of hydrological changes from global closed basins since the last glacial maximum

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