scholarly journals Late Pleistocene Age of the Type Temple Lake Moraine, Wind River Range, Wyoming, U.S.A.

2007 ◽  
Vol 41 (3) ◽  
pp. 397-401 ◽  
Author(s):  
Gregory A. Zielinski ◽  
P. Thompson Davis

ABSTRACT The type Temple Lake moraine lies about 3 km beyond and roughly 120 m lower than the modern glacier margin and the Gannett Peak (Little Ice Age) moraines deposited in the last few centuries. Because numerous glacial deposits throughout the western United States have been correlated to the Temple Lake moraine its age is important. We retrieved two sediment cores up to six meters long from Rapid Lake, outside the outer type Temple Lake moraine. The 383-413 cm depth dates 11,770 ± 710 yrs (GX-11,772), which we believe reflects the time when silt flux into Rapid Lake was abruptly reduced by the formation of a new sediment trap at Miller Lake as the valley glacier receded from its position at the outer Temple Lake moraine. A radiocarbon date of 11,400 ± 630 yrs BP (GX-12,719) obtained from the lower basin of Temple Lake, inside the inner type Temple Lake moraine, supports this interpretation. Sediments from Miller Lake, inside the outer Temple Lake moraine, that date 8300 ± 475 yrs BP (GX-12,277) are probably well above the bottom of the lake sediment sequence and possibly thousands of years younger than the moraine. We feel that the type Temple Lake moraine dates about 12,000 yrs BP, thus is Late Pleistocene in age. This interpretation is supported by maximum percentages of organic detritus in lake sediments between 10,000 and 8,000 yrs BP, and challenges BEGET's (1983) suggestion that the type Temple Lake moraine is early Holocene in age, a period he calls "Mesogiaciation".

The Holocene ◽  
2014 ◽  
Vol 24 (11) ◽  
pp. 1439-1452 ◽  
Author(s):  
José M García-Ruiz ◽  
David Palacios ◽  
Nuria de Andrés ◽  
Blas L Valero-Garcés ◽  
Juan I López-Moreno ◽  
...  

The Marboré Cirque, which is located in the southern Central Pyrenees on the north face of the Monte Perdido Peak (42°40′0″N; 0.5°0″W; 3355 m), contains a wide variety of Holocene glacial and periglacial deposits, and those from the ‘Little Ice Age’ (‘LIA’) are particularly well developed. Based on geomorphological mapping, cosmogenic exposure dating and previous studies of lacustrine sediment cores, the different deposits were dated and a sequence of geomorphological and paleoenvironmental events was established as follows: (1) The Marboré Cirque was at least partially deglaciated before 12.7 kyr BP. (2) Some ice masses are likely to have persisted in the Early Holocene, although their moraines were destroyed by the advance of glaciers during the Mid Holocene and ‘LIA’. (3) A glacial expansion occurred during the Mid Holocene (5.1 ± 0.1 kyr), represented by a large push moraine that enclosed a unique ice mass at the foot of the Monte Perdido Massif. (4) A melting phase occurred at approximately 3.4 ± 0.2 and 2.5 ± 0.1 kyr (Bronze/Iron Ages) after one of the most important glacial advances of the Neoglacial period. (5) Another glacial expansion occurred during the Dark Age Cold Period (1.4–1.2 kyr), followed by a melting period during the Medieval Climate Anomaly. (6) The ‘LIA’ represented a clear stage of glacial expansion within the Marboré Cirque. Two different pulses of glaciation were detected, separated by a short retraction. The first pulse occurred most likely during the late 17th century or early 18th century (Maunder Minimum), whereas the second occurred between 1790 and ad 1830 (Dalton Minimum). A strong deglaciation process has affected the Marboré Cirque glaciers since the middle of the 19th century. (7) A large rock avalanche occurred during the Mid Holocene, leaving a chaotic deposit that was previously considered to be a Late Glacial moraine.


2003 ◽  
Vol 60 (3) ◽  
pp. 294-306 ◽  
Author(s):  
Kenneth D. Adams

AbstractNew dating in the Carson Sink at the termini of the Humboldt and Carson rivers in the Great Basin of the western United States indicates that lakes reached elevations of 1204 and 1198 m between 915 and 652 and between 1519 and 1308 cal yr B.P., respectively. These dates confirm Morrison's original interpretation (Lake Lahontan: Geology of the Southern Carson Desert, Professional Paper 40, U.S. Geol. Survey, 1964) that these shorelines are late Holocene features, rather than late Pleistocene as interpreted by later researchers. Paleohydrologic modeling suggests that discharge into the Carson Sink must have been increased by a factor of about four, and maintained for decades, to account for the 1204-m lake stand. The hydrologic effects of diversions of the Walker River to the Carson Sink were probably not sufficient, by themselves, to account for the late Holocene lake-level rises. The decadal-long period of increased runoff represented by the 1204-m lake is also reflected in other lake records and in tree ring records from the western United States.


2018 ◽  
Author(s):  
Daniel Enrique Ibarra

Knowledge of Earth’s climate history and sensitivity, combined with modeling past and future climate, are central to informing policy decisions regarding future climate change. The hydrologic response to future warming scenarios due to increased anthropogenic CO2 emissions remains uncertain. Freshwater availability in the arid western United States is projected to decrease in availability as increased agricultural, urban and industrial uses continue to stress supplies. Motivated by the potential for dramatic future hydrologic changes, studies recording the abrupt transitions between different equilibrium states of natural past climate variability shed light on our understanding of the modern climate system.The presence of pluvial lakes in the Basin and Range Province, in the western United States, during the late Pleistocene (40 to 10 ka) indicates far greater moisture availability during the Pleistocene glacials. This study investigates the timing and magnitude of the most recent pluvial lake cycle that filled Surprise Valley, California using geophysical, geochemical and geochronologic tools. Spanning 31.2 to 4.6 ka, this new lake level record places the highest lake level, at 180 meters above present day playa, at 13.9 ± 1.2 ka. This age appears to be nearly synchronous with highstands of Lake Lahontan to the south and the Chewaucan Basin to the north. Additionally, most of the Basin and Range lake highstands, including Lake Surprise, follow peaks in precipitation minus evapotranspiration (P-ET) by 8-10 kyr. By compiling a diverse set of paleoclimate data available for western North America, I found that the timing and geographic distribution of lake highstands is inconsistent with increased precipitation in response to shifting westerly winds, the current model for the genesis of large lakes in western North America. Rather, lakes levels are more strongly correlated with changes in summer insolation, suggesting that lake highstands were likely facilitated by colder temperatures and increased humidity due to the presence of continental ice sheets and increased atmospheric convergence. I compared the constraints from lake and soil-based records to Atmosphere-Ocean General Circulation Model simulations from the Paleoclimate Model Intercomparison Project 2. Based on model-proxy intercomparison, the Atmosphere-Ocean General Circulation Models, the same models used to also assess future climatic changes, poorly predict hydrologic quantities for the Last Glacial Maximum.


The Holocene ◽  
2021 ◽  
pp. 095968362110604
Author(s):  
Mauro Caffau ◽  
Emanuele Lodolo ◽  
Federica Donda ◽  
Massimo Zecchin ◽  
Jorge G Lozano ◽  
...  

The spectacular water outburst occurring semi-periodically when the ice-dam formed by the external front of the Perito Moreno glacier collapses, is one of the most attracting events in the UNESCO ‘Parque Nacional Los Glaciares’ of southern Patagonia. These occurrences have been documented since 1936. Instead, evidence of previous events has been only indirectly provided by dendrochronology analysis. Here we show for the first time radiocarbon-dated sediment cores collected within a small inlet of Brazo Sur, that is, the southern arm of Lago Argentino that record ice-dammings in the Little Ice Age, at 324–266 cal yrs BP, as measured on a vegetal fragment sampled at ca. 14 cm from the top of a core. A common characteristic of the three sediment cores is the abrupt change in the stratigraphic record found at variable depths of 14–18 cm from the top of the cores. This change is marked by a hiatus spanning ca. 3200 years, separating planar-laminated sediments below from an alternation of erosional and depositional events above it, indicating recurring high-energy conditions generated by the emptying of the lake basin. In addition, we observed significant changes in the abundance of environmental indicators as testate amoebae below and above the hiatus. These well-preserved stratigraphic records highlight the key role of glaciolacustine deposits in reconstructing the glacial dynamics and palaeoclimate evolution of a glaciated region.


2016 ◽  
Vol 37 (1) ◽  
pp. 23-48 ◽  
Author(s):  
Antti E.K. Ojala ◽  
Laura Arppe ◽  
Tomi P. Luoto ◽  
Lukas Wacker ◽  
Eija Kurki ◽  
...  

Abstract The sedimentary environment, sediment characteristics and age-depth models of sediment sequences from Arctic lakes Revvatnet and Svartvatnet, located near the Polish Polar Station in Hornsund, southern Svalbard (77°N), were studied with a view to establishing a basis for paleolimnological climate and environmental reconstructions. The results indicate that catchment-to-lake hydroclimatic processes probably affect the transportation, distribution and accumulation of sediments in different parts of lakes Revvatnet and Svartvatnet. Locations with continuous and essentially stable sedimentary environments were found in both lakes between water depths of 9 and 26 m. We used several different dating techniques, including 137Cs, 210Pb, AMS 14C, and paleomagnetic dating, to provide accurate and secured sediment chronologies. Arecovered sequence from the northern basin of Revvatnet spans more than one thousand years long with laminated stratigraphy in the upper part of the sediment. Based on AMS 14C dates, it is possible to suppose that Revvatnet basin was not occupied by a valley glacier during the Little Ice Age. The dates were supported by 137Cs chronologies, but not confirmed with other independent dating methods that extent beyond the last 50 years. A sedimentary sequence from the northern basin of Svartvatnet provides a potential archive for the study of climate and environmental change for the last ca. 5000 years. Based on the stratigraphy and a Bayesian age-depth model of AMS14C and paleosecular variation (PSV) dates, the recovered sediment sections represent a continuous and stable sedimentation for the latter half of the Holocene.


2018 ◽  
Vol 91 (1) ◽  
pp. 367-382 ◽  
Author(s):  
Priyanka Raja ◽  
Hema Achyuthan ◽  
Anjum Farooqui ◽  
Rengaswamy Ramesh ◽  
Pankaj Kumar ◽  
...  

AbstractA multiproxy study involving sedimentology, palynology, radiocarbon dating, stable isotopes, and geochemistry was carried out on the Parsons Valley Lake deposit, Nilgiris, India, to determine palaeoclimatic fluctuations and their possible impact on vegetation since the late Pleistocene. The 72-cm-deep sediment core that was retrieved reveals five distinct palaeoclimatic phases: (1) Warm and humid conditions with a high lake stand before the last glacial maximum (LGM; ~29,800 cal yr BP), subsequently changing to a relatively cool and dry phase during the LGM. (2) Considerable dry conditions and lower precipitation occurred between ~16,300 and 9500 cal yr BP. During this period, the vegetation shrank and perhaps was confined to moister pockets or was a riparian forest cover. (3) An outbreak in the shift of monsoonal precipitation was witnessed in the beginning of the mid-Holocene, around 8400 cal yr BP, implying alteration in the shift toward warm and humid conditions, resulting in relatively high pollen abundance for evergreen taxa. (4) This phase exhibits a shift to heavier δ13C values around ~1850 cal yr BP, with an emergence of moist deciduous plants pointing to drier conditions. (5) Human activities contributed to the exceedingly high percentage ofAcaciaandPinuspollen during the Little Ice Age.


1986 ◽  
Vol 8 ◽  
pp. 65-68 ◽  
Author(s):  
Jane G. Ferrigno

Grasshopper Glacier is a cirque glacier in the central Rocky Mountains of the United States. It is a remnant of the “Little Ice Age”, rather than the more widespread and older Pinedale Glaciation. The glacier has not been monitored on a regular basis and very few maps have been published of the area, but it has been studied, photographed, occasionally mapped, and described by scientific and non-scientific groups, at different times since 1898. These photographic, cartographic, and written records make it possible to trace the fluctuations of this glacier since 1898. Grasshopper Glacier has had periods of positive mass balance, but the overall trend has been negative, with accelerated melting in recent years. It is estimated that Grasshopper Glacier has lost about 50% of its area and as much as 90% of its volume, since 1898. Other Rocky Mountain glaciers are experiencing similar wastage and, if current conditions continue, these glaciers will disappear by the middle of the next century.


1986 ◽  
Vol 8 ◽  
pp. 65-68 ◽  
Author(s):  
Jane G. Ferrigno

Grasshopper Glacier is a cirque glacier in the central Rocky Mountains of the United States. It is a remnant of the “Little Ice Age”, rather than the more widespread and older Pinedale Glaciation. The glacier has not been monitored on a regular basis and very few maps have been published of the area, but it has been studied, photographed, occasionally mapped, and described by scientific and non-scientific groups, at different times since 1898. These photographic, cartographic, and written records make it possible to trace the fluctuations of this glacier since 1898. Grasshopper Glacier has had periods of positive mass balance, but the overall trend has been negative, with accelerated melting in recent years. It is estimated that Grasshopper Glacier has lost about 50% of its area and as much as 90% of its volume, since 1898. Other Rocky Mountain glaciers are experiencing similar wastage and, if current conditions continue, these glaciers will disappear by the middle of the next century.


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