TY - JOUR
T1 - Radiocarbon and cation-radio ages for rock varnish on Tioga and Tahoe marainal boulders of Pine Creek, eastern Sierra Nevada, California, and their paleoclimatic implications
AU - Dorn, Ronald I.
AU - Turrin, Brent D.
AU - Jull, A. J.Timothy
AU - Linick, Timothy W.
AU - Donahue, Douglas J.
N1 - Funding Information:
Rock varnish work was funded by NSF Grant SES 86-01937. The accelerator facility is funded by NSF Grant EAR-8309448. K-Ar dating was supported by the Department of Energy, and the Land Processes Branch of NASA through Cal-Tech/Jet Propulsion Laboratory to Alan Gillespie. Thanks to Denise Dom and Alan Gillespie for field assistance and L. J. Toolin and L. F. Warneke for technical assistance. Comments by Brian Atwater, Margaret Berry, Peter W. Birkeland, Owen K. Davis, Debbie Elliot-Fisk, and Scott Stine improved the manuscript.
PY - 1987/7
Y1 - 1987/7
N2 - Accelerator mass spectrometry 14C analyses of organic matter extracted from rock varnishes on morainal boulders yield limiting minimum ages for three crests of the Tioga glaciation. At Pine Creek in the eastern Sierra Nevada, varnish started to form on boulders of the outermost Tioga moraine before 19,000 yr B.P., and varnish originated on the innermost Tioga moraine before 13,200 yr B.P. Comparisons with lake-level, paleohydrological, paleoecological, colluvial, and rock varnish micromorphological data indicate that central-eastern California and western Nevada experienced a moisture-effective period during the late Pleistocene but after the Tioga maximum, and perhaps as Tioga glaciers receded from the mouth of Pine Creek canyon. Varnishes on Tahoeage morainal boulders at Pine Creek have cation-ratio ages of about 143,000-156,000 yr B.P., suggesting that the Tahoe glaciation should not be correlated with oxygen-isotope stage 4 in the early Wisconsin, but rather with stage 6. Varnishes on morainal boulders of an older glaciation at Pine Creek are dated by cation ratio at about 182,000-187,000 yr B.P.
AB - Accelerator mass spectrometry 14C analyses of organic matter extracted from rock varnishes on morainal boulders yield limiting minimum ages for three crests of the Tioga glaciation. At Pine Creek in the eastern Sierra Nevada, varnish started to form on boulders of the outermost Tioga moraine before 19,000 yr B.P., and varnish originated on the innermost Tioga moraine before 13,200 yr B.P. Comparisons with lake-level, paleohydrological, paleoecological, colluvial, and rock varnish micromorphological data indicate that central-eastern California and western Nevada experienced a moisture-effective period during the late Pleistocene but after the Tioga maximum, and perhaps as Tioga glaciers receded from the mouth of Pine Creek canyon. Varnishes on Tahoeage morainal boulders at Pine Creek have cation-ratio ages of about 143,000-156,000 yr B.P., suggesting that the Tahoe glaciation should not be correlated with oxygen-isotope stage 4 in the early Wisconsin, but rather with stage 6. Varnishes on morainal boulders of an older glaciation at Pine Creek are dated by cation ratio at about 182,000-187,000 yr B.P.
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U2 - 10.1016/0033-5894(87)90031-7
DO - 10.1016/0033-5894(87)90031-7
M3 - Article
AN - SCOPUS:45949117208
SN - 0033-5894
VL - 28
SP - 36
EP - 49
JO - Quaternary Research
JF - Quaternary Research
IS - 1
ER -