Lake Qinghai 17,000 Year Sediment Visible Reflectance Data Ji, J.; Shen, J.; Balsam, W.; Chen, J.; Liu, L. Ji, J. Shen, J. Balsam, W. Chen, J. Liu, L. earth science/paleoclimate/paleolimnology (depth,null,null,centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (lightness,sediment,null,peak area integral,null,paleolimnology,null,spectrophotometry,N,brightness; nm*percent) earth science/paleoclimate/paleolimnology (age,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (red intensity,sediment,null,percent,null,paleolimnology,null,spectrophotometry,N,size fraction > 150 microns) earth science/paleoclimate/paleolimnology (Lake Qinghai>LATITUDE 37.058>LONGITUDE 100.303) Qinghai Lake is a large saline lake on the Qinghai-Tibetan Plateau of central Asia that is effected by both the Indian and Asian monsoons. We used reflectance spectroscopy to characterize the sediments in a 795-cm long core taken from the southeastern part of the lake. Sediment redness, which is related to iron oxide content, seems to monitor paleoclimatic changes in the core. Iron oxides appear to be eroded from nearby red beds or loess deposits and are transported by fluvial means into the lake. Thus, redness increases at times of increased precipitation, that is, as monsoon strength increases. Our redness monsoon proxy shows climate changes on several times scales. On a millennial scale, it records humid conditions during the Early and Mid-Holocene. From about 4200 to 2300 yr BP, low redness values suggest a two-millennial long dry period, which in the Late Holocene is followed by a more humid period. On a centennial scale, the redness proxy records not only the Little Ice Age, but also the Medieval Warm Period, the Dark Ages Cool Period and the Roman Warm Period. Time series analysis of the redness record indicates a 200 yr frequency, which corresponds to the de Vries solar cycle suggesting that, in addition to insolation changes resulting from orbital variations, solar forcing also results from cyclic changes in the sun's luminosity. STUDY NOTES: Sediment optical properties (brightness and %redness) data from a core in Lake Qinghai, central China, for the last 17,000 years. Sediment redness is a function of iron oxide content, eroded from nearby red beds or loess deposits, and thus is a proxy for increased precipitation and monsoon strength. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Ji, J. Investigator : Shen, J. Investigator : Balsam, W. Investigator : Chen, J. Investigator : Liu, L. 2009-01-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/8643 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/asia/china/qinghai2005.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/asia/china/qinghai2005.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/asia/china/qinghai2005.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/asia/china/qinghai2005.txt English https://www.ncdc.noaa.gov/paleo/study/8643 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/asia/china/qinghai2005.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/asia/china/qinghai2005.txt Ji, J., Shen, J., Balsam, W., Chen, J., Liu, L., Liu, X. 2005. Asian monsoon oscillations in the northeastern Qinghaiŋ-Tibet Plateau since the late glacial as interpreted from visible reflectance of Qinghai Lake sediments. Earth and Planetary Science Letters, 233(1-2), 61-70. START YEAR: 17404 cal yr BP * END YEAR: 31 cal yr BP 100.303 37.058 100.303 37.058