DOI: 10.1016/j.palaeo.2015.01.012
论文题名: Fluvial tufa evidence of Late Pleistocene wet intervals from Santa Barbara, California, U.S.A.
作者: Ibarra Y. ; Corsetti F.A. ; Feakins S.J. ; Rhodes E.J. ; Kirby M.E.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2015
卷: 422 起始页码: 36
结束页码: 45
语种: 英语
英文关键词: Infra-red stimulated luminescence
; Palaeoclimate
; Pluvial
; Radiocarbon
; Tufa
英文摘要: Past pluvials in the western United States provide valuable context for understanding regional hydroclimate variability. Here we report evidence of conditions substantially wetter than today from fluvial tufa deposits located near Zaca Lake, Santa Barbara County, California that have been dated by radiocarbon (14C) and Infra-Red Stimulated Luminescence (IRSL). Two successions of tufa deposition occur within a small catchment that drains Miocene Monterey Formation bedrock: 1) a fluvial deposit (0-0.5m thick, 200m in extent) that formed along a narrow valley below a modern spring, and 2) a perched deposit ~10m higher (2m thick, 15m in extent). IRSL and radiocarbon dating of the perched carbonates suggest at least two episodes of carbonate growth: one at 19.4±2.4 (1σ) through 17.8±2.8 (1σ)ka and another at 11.9±1.5 (1σ)ka verified with a charcoal 14C age of 10.95±0.12 (2σ)calkaBP. The relationship between the perched and fluvial spring deposits is inferred to represent a drop in the water table of more than 10m associated with a transition from a wet climate in the late glacial to a dry Holocene today. The wet period indicated by the perched tufa deposit between 19.4 and 17.8. ka is relatively consistent with other California climate records both north and south of Zaca Lake. However, tufa growth ca. 12 to 11. ka demonstrates wet conditions occurred as far south as Zaca Lake during the Younger Dryas event, in contrast to climate records farther south in Lake Elsinore that indicate a drying trend through this interval. A small shift north in the average position of the winter season storm track could explain wet winters at Zaca while at the same time generating dry winters at Lake Elsinore, ~. 275. km southwest of Zaca. If true, these data indicate that rather small latitudinal shifts in the average winter season storm track can produce large changes in regional hydroclimate. © 2015 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69020
Appears in Collections: 过去全球变化的重建
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作者单位: University of Southern California, Department of Earth Sciences, 3651 Trousdale Avenue, Los Angeles, CA, United States; University of California, Los Angeles, Department of Earth and Space Sciences, 595 Charles Young Drive East, Los Angeles, CA, United States; California State University, Fullerton, Department of Geological Sciences, Fullerton, CA, United States
Recommended Citation:
Ibarra Y.,Corsetti F.A.,Feakins S.J.,et al. Fluvial tufa evidence of Late Pleistocene wet intervals from Santa Barbara, California, U.S.A.[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2015-01-01,422