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1. Thermal legacy of a large paleolake in Taylor Valley, East Antarctica, as evidenced by an airborne electromagnetic survey

   https://doi.org/10.5194/tc-15-3577-2021  

   Myers, Krista F.; Doran, Peter T.; Tulaczyk, Slawek M.; Foley, Neil T.; Bording, Thue S.; Auken, Esben; Dugan, Hilary A.; Mikucki, Jill A.; Foged, Nikolaj; Grombacher, Denys; et al (January 2021, The Cryosphere)

   null (Ed.)

   Abstract. Previous studies of the lakes of the McMurdo Dry Valleys haveattempted to constrain lake level history, and results suggest the lakeshave undergone hundreds of meters of lake level change within the last20 000 years. Past studies have utilized the interpretation of geologicdeposits, lake chemistry, and ice sheet history to deduce lake levelhistory; however a substantial amount of disagreement remains between thefindings, indicating a need for further investigation using new techniques.This study utilizes a regional airborne resistivity survey to provide novelinsight into the paleohydrology of the region. Mean resistivity mapsrevealed an extensive brine beneath the Lake Fryxell basin, which isinterpreted as a legacy groundwater signal from higher lake levels in thepast. Resistivity data suggest that active permafrost formation has beenongoing since the onset of lake drainage and that as recently as 1500–4000 years BP, lake levels were over 60 m higher than present. This coincideswith a warmer-than-modern paleoclimate throughout the Holocene inferred bythe nearby Taylor Dome ice core record. Our results indicate Mid to LateHolocene lake level high stands, which runs counter to previous researchfinding a colder and drier era with little hydrologic activity throughoutthe last 5000 years. 

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2. Bugeye Lakes Complex Water Level Sensor Data, Arctic Coastal Plain of northern Alaska, 2021-2022

   https://doi.org/10.18739/A21V5BG0D  

   Jones, Benjamin (January 2023, NSF Arctic Data Center)

   Taken together, lakes and drained lake basins may cover up to 80% of the lowland landscapes in permafrost regions of the Arctic. Lake formation, growth, and drainage in lowland permafrost regions create a terrestrial and aquatic landscape mosaic of importance to geomorphic and hydrologic processes, tundra vegetation communities, permafrost and ground-ice characteristics, biogeochemical cycling, wildlife habitat, and human land-use activities. Our project focuses on quantifying the role of thermokarst lake expansion, drainage, and drained lake basin evolution in the Arctic System. We did this through a combination of field studies, environmental sensor networks, remote sensing, and modeling. This dataset consists of environmental sensor records that record temperature and water level at three lakes in the Bugeye Lakes Complex in 2021 and 2022. Onset HOBO water level loggers (U2OL-04) were deployed in Bugeye Lakes 1, 2, and 4 in 2021 and 2022 to record temperature and pressure changes at 30-minute intervals. Water level was determined in Onset Hoboware Pro v. 3.7.23 using the barometric compensation assistant based on pressure transducer measurements below the water and from nearby atmospheric pressure measurements from a local pressure transducer mounted to pole on the tundra. The sensor data capture the partial drainage of Bugeye Lakes 2 and 4 into Bugeye Lake 1. Bugeye Lakes 1 and 2 also measure snow dam outburst flooding associated with the recently drained lake basins. 

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3. Holocene Rupture History of the Central Teton Fault at Leigh Lake, Grand Teton National Park, Wyoming

   https://doi.org/10.1785/0120190129  

   Zellman, Mark S.; DuRoss, Christopher B.; Thackray, Glenn D.; Personius, Stephen F.; Reitman, Nadine G.; Mahan, Shannon A.; Brossy, Cooper C. (November 2019, Bulletin of the Seismological Society of America)

   Abstract Prominent scarps on Pinedale glacial surfaces along the eastern base of the Teton Range confirm latest Pleistocene to Holocene surface‐faulting earthquakes on the Teton fault, but the timing of these events is only broadly constrained by a single previous paleoseismic study. We excavated two trenches at the Leigh Lake site near the center of the Teton fault to address open questions about earthquake timing and rupture length. Structural and stratigraphic evidence indicates two surface‐faulting earthquakes at the site that postdate deglacial sediments dated by radiocarbon and optically stimulated luminescence to ∼10–11  ka. Earthquake LL2 occurred at ∼10.0  ka (9.7–10.4 ka; 95% confidence range) and LL1 at ∼5.9  ka (4.8–7.1 ka; 95%). LL2 predates an earthquake at ∼8  ka identified in the previous paleoseismic investigation at Granite Canyon. LL1 corresponds to the most recent Granite Canyon earthquake at ∼4.7–7.9  ka (95% confidence range). Our results are consistent with the previously documented long‐elapsed time since the most recent Teton fault rupture and expand the fault’s earthquake history into the early Holocene. 

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4. Holocene water balance variations in Great Salt Lake, Utah: Application of GDGT indices and the ACE salinity proxy

   https://doi.org/10.1029/2022PA004558  

   So, Rachel T.; Lowenstein, Tim K.; Jagniecki, Elliot; Tierney, Jessica E.; Feakins, Sarah J. (January 2023, Paleoceanography and Paleoclimatology)

   Abstract Great Salt Lake, Utah, is a hypersaline terminal lake in the Great Basin, and the remnant of the late glacial Lake Bonneville. Holocene hydroclimate variations cannot be interpreted from the shoreline record, but instead can be investigated by proxies archived in the sediments. GLAD1-GSL00-1B was cored in 2000 and recently dated by radiocarbon for the Holocene section with the top 11 m representing ∼7 ka to present. Sediment samples every 30 cm (∼220 years) were studied for the full suite of microbial membrane lipids, including those responsive to temperature and salinity. The Archaeol and Caldarchaeol Ecometric (ACE) index detects the increase in lipids of halophilic archaea, relative to generalists, as salinity increases. We find Holocene ACE values ranged from 81-98, which suggests persistent hypersalinity with <50 g/L variability across 7.2 ka. The temperature proxy, MBTʹ5Me, yields values similar to modern mean annual air temperature for months above freezing (MAF = 15.7°C) over the last 5.5 ka. Several GDGT metrics show a step shift in microbial communities and limnology at 5.5 ka. Extended archaeol detects elevated salinity during the regional mid-Holocene drought, not readily detected in the ACE record that is often near the upper limit of the index. We infer that the mid-Holocene GSL was shallower and saltier than the late Holocene. The current drying may be returning the lake to conditions not seen since the mid-Holocene. Plain Language Summary Great Salt Lake in Utah is the remnant of a once much larger lake and is currently at a historically low level. We study a lake sediment core, collected in 2000 from the floor of Great Salt Lake, and recently dated. We take new samples from the core and measure them for molecules made by microbes, whether living in the lake or washed in from the surrounding soils. We reconstruct lake conditions during the last 7,200 years and assess whether lake level fluctuated during that time. Over the past 7,200 years, we find evidence that the lake was shallower from 7,200 to 5,500 years ago but has been relatively stable until the modifications of the lake in the 20th century and the current drying trend. 

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5. Searles Lake evaporite sequences: Indicators of late Pleistocene/Holocene lake temperatures, brine evolution, and p CO2

   https://doi.org/10.1130/B35857.1  

   Olson, Kristian J.; Lowenstein, Tim K. (March 2021, GSA Bulletin)

   null (Ed.)

   Searles Lake, California, was a saline-alkaline lake that deposited >25 non-clastic minerals that record the history of lake chemistry and regional climate. Here, the mineralogy and petrography from the late Pleistocene/Holocene (32−6 ka) portion of a new Searles Lake sediment core, SLAPP-SRLS17, is combined with thermodynamic models to determine the geochemical and paleoclimate conditions required to produce the observed mineral phases, sequences, and abundances. The models reveal that the primary precipitates formed by open system (i.e., fractional crystallization), whereas the early diagenetic salts formed by salinity-driven closed system back-reactions (i.e., equilibrium crystallization). For core SLAPP-SRLS17, the defining evaporite sequence trona → burkeite → halite indicates brine temperatures within a 20−29 °C range, implying thermally insulating lake depths >10 m during salt deposition. Evaporite phases reflect lake water pCO2 consistent with contemporaneous atmospheric values of ∼190−270 ppmv. However, anomalous layers of nahcolite and thenardite indicate pulses of pCO2 > 700−800 ppm, likely due to variable CO2 injection along faults. Core sedimentology indicates that Searles Lake was continuously perennial between 32 ka and 6 ka such that evaporite units reflect periods of net evaporation but never complete desiccation. Model simulations indicate that cycles of partial evaporation and dilution strongly influence long-term brine evolution by amassing certain species, particularly Cl−, that only occur in late-stage soluble salts. A model incorporating long-term brine dynamics corrects previous mass-balance anomalies and shows that the late Pleistocene/Holocene (32−6 ka) salts are partially inherited from the solutes introduced into earlier lakes going back at least 150 ka. 

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