ERUPTION STYLES AND LATE PLEISTOCENE AGES FROM 36CL DATING OF GROUNDHOG CONE, THE MOST RECENT AND UNGLACIATED BASALTIC VOLCANO IN THE GOLDEN TROUT VOLCANIC FIELD, KERN PLATEAU, SIERRA NEVADA

AbstractSeven packrat midden samples make possible a comparison between the modern and late Pleistocene vegetation in Kings Canyon on the western side of the southern Sierra Nevada. One modern sample contains macrofossils and pollen derived from the present-day oak-chaparral vegetation. Macrofossils from the six late Pleistocene samples record a mixed coniferous forest dominated by the xerophytic conifers Juniperus occidentalis, Pinus cf. ponderosa, and P. monophylla. The pollen spectra of these Pleistocene middens are dominated by Pinus sp., Taxodiaceae-Cupressaceae-Taxaceae (TCT), and Artemisia sp. Mesophytic conifers are represented by low macrofossil concentrations. Sequoiadendron giganteum is represented by a few pollen grains in the full glacial. Edaphic control and snow dispersal are the most likely causes of these mixed assemblages.The dominant macrofossils record a more xeric plant community than those that now occur on similar substrates at higher elevations or latitudes in the Sierra Nevada. These assemblages suggest that late Wisconsin climates were cold with mean annual precipitation not necessarily greater than modern values. This conclusion supports a model of low summer ablation allowing for the persistence of the glaciers at higher elevations during the late Wisconsin. The records in these middens also suggest that S. giganteum grew at lower elevations along the western side of the range and that P. monophylla was more widely distributed in cismontane California during the Pleistocene.

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Timing of the last Deglaciation in the Sierra Nevada of the Mérida Andes, Venezuela

Quaternary Research ◽

10.1016/j.yqres.2013.08.001 ◽

2013 ◽

Vol 80 (3) ◽

pp. 482-494 ◽

Cited By ~ 13

Author(s):

Julien Carcaillet ◽

Isandra Angel ◽

Eduardo Carrillo ◽

Franck A. Audemard ◽

Christian Beck

Keyword(s):

Sierra Nevada ◽

Late Pleistocene ◽

Younger Dryas ◽

Ice Cover ◽

Published Data ◽

Last Deglaciation ◽

The Last Deglaciation ◽

Absolute Age ◽

Glacial Landforms

In the tropical Mérida Andes (northwestern Venezuela), glacial landforms were found at altitudes between 2600 and 5000 m, corresponding to 600 km2 of ice cover during the maximum glacial extension. However, the lack of sufficient absolute age data prevents detailed reconstruction of the timing of the last deglaciation. On the northwestern flank of the Mucuñuque Massif, successive moraines and striated eroded basement surfaces were sampled for cosmogenic 10Be investigation. Their compilation with published data allows the establishment of a detailed chronology of the post-LGM glacier history. The oldest moraines (18.1 and 16.8 ka) correspond to the Oldest Dryas. Successive moraine ridges indicate stops in the overall retreat between the LGM and the Younger Dryas. The cold and short Older Dryas stadial has been identified. Results indicate that most of the ice withdrew during the Pleistocene. The dataset supports an intensification of the vertical retreat rate from ~ 25 m/ka during the late Pleistocene to ~ 310 m/ka during the Pleistocene/Holocene. Afterwards, the glacier was confined and located in the higher altitude zones. The altitude difference of the Younger Dryas moraines in the Mucubají, La Victoria and Los Zerpa valleys indicates a strong effect of valley orientation on the altitude of moraine development.

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Late Pleistocene rhyolitic explosive volcanism at Los Azufres Volcanic Field, central Mexico

The Southern Cordillera and Beyond ◽

10.1130/2012.0025(04) ◽

2012 ◽

pp. 45-82 ◽

Cited By ~ 3

Author(s):

José Luis Arce ◽

José Luis Macías ◽

Elizabeth Rangel ◽

Paul Layer ◽

Víctor Hugo Garduño-Monroy ◽

...

Keyword(s):

Late Pleistocene ◽

Explosive Volcanism ◽

Volcanic Field ◽

Central Mexico

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Late Pleistocene and Late Holocene Lake Highstands in the Pyramid Lake Subbasin of Lake Lahontan, Nevada, USA

Quaternary Research ◽

10.1016/j.yqres.2005.02.011 ◽

2005 ◽

Vol 64 (2) ◽

pp. 257-263 ◽

Cited By ~ 39

Author(s):

Richard W. Briggs ◽

Steven G. Wesnousky ◽

Kenneth D. Adams

Keyword(s):

Sierra Nevada ◽

Late Pleistocene ◽

Late Holocene ◽

Large Lakes ◽

Western Basin ◽

Radiocarbon Dates ◽

Beach Ridges ◽

Climate Proxy ◽

Pyramid Lake ◽

Proxy Records

AbstractShoreline geomorphology, shoreline stratigraphy, and radiocarbon dates of organic material incorporated in constructional beach ridges record large lakes during the late Pleistocene and late Holocene in the Pyramid Lake subbasin of Lake Lahontan, Nevada, USA. During the late Holocene, a transgression began at or after 3595 ± 35 14C yr B.P. and continued, perhaps in pulses, through 2635 ± 40 14C yr B.P., resulting in a lake as high as 1199 m. During the latest Pleistocene and overlapping with the earliest part of the Younger Dryas interval, a lake stood at approximately 1212 m at 10,820 ± 35 14C yr B.P. and a geomorphically and stratigraphically distinct suite of constructional shorelines associated with this lake can be traced to 1230 m. These two lake highstands correspond to periods of elevated regional wetness in the western Basin and Range that are not clearly represented in existing northern Sierra Nevada climate proxy records.

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