DOI: 10.1016/j.quascirev.2015.09.011
Scopus记录号: 2-s2.0-84949216261
论文题名: Timing and characteristics of Late Pleistocene and Holocene wetter periods in the Eastern Desert and Sinai of Egypt, based on 14C dating and stable isotope analysis of spring tufa deposits
作者: Hamdan M.A. ; Brook G.A.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2015
卷: 130 起始页码: 168
结束页码: 188
语种: 英语
英文关键词: Eastern Desert
; Egypt
; Holocene
; Isotopes
; Paleoclimate
; Pleistocene
; Sinai
; Tufa
Scopus关键词: Carbon
; Deposits
; Exploratory geochemistry
; Groundwater
; Igneous rocks
; Isotopes
; Metamorphic rocks
; Petrography
; Rain
; Sea level
; Volcanic rocks
; Eastern Desert
; Egypt
; Holocenes
; Paleoclimates
; Pleistocene
; Sinai
; Tufa
; Landforms
; geochemistry
; geochronology
; Heinrich event
; Holocene
; oxygen isotope
; paleoclimate
; petrography
; Pleistocene
; radiocarbon dating
; sapropel
; tufa
; Arabian Sea
; Eastern Desert
; Egypt
; Gulf of Aden
; Indian Ocean
; Mediterranean Sea
; Red Sea [Indian Ocean]
; Sinai
英文摘要: There is very little dated evidence on wet periods in the Eastern Desert and Sinai Peninsula of Egypt during the Late Pleistocene and Holocene. To obtain such information, we have studied the petrography, isotope geochemistry and AMS radiocarbon ages of mostly relict tufas deposited by springs draining perched ground water bodies in metamorphic and volcanic rocks. The tufas unconformably overly Precambrian basic igneous rocks (basalt, diabase and gabbro). As the ages of tufa carbonate are frequently older than the true ages of the deposits because of the incorporation of old, 14C-dead carbon, we have dated both the carbonate matrix and insoluble organic material of the tufas. These ages show that the tufas were largely formed during two broad time periods, the most recent from 12,058 to 6678 cal yr BP (African Humid Period), and the other from ~31,200-22,500 cal yr BP, with preferential growth during the coldest times of this period namely during Heinrich Events 2 and 3 (H2 and H3) and the Last Glacial Maximum (LGM). The time span between 19,000-9000 cal yr BP, including the YD and H1, appears to have been relatively more arid than the earlier LGM or H2 periods or the later Holocene. The Late Pleistocene tufas are depleted in 18O relative to the Holocene tufas and were deposited at a lower temperature (~14.0°-20.8 °C vs. 18.4°-23.4 °C). We believe that the Holocene tufas in the Sinai were formed by rainfall from the Mediterranean and those in the southern part of the Eastern Desert by African monsoon rainfall derived from the Red Sea-Gulf of Aden and Indian Ocean. In contrast, the moisture that fed the Late Pleistocene tufas, which are depleted in 18O relative to Holocene deposits, and progressively depleted from north to south, was probably brought by the Westerlies from the Atlantic-Mediterranean Sea when the Westerly circulation was pushed southwards during the coldest periods of the Late Pleistocene. Periods of tufa deposition correlate with major documented paleoclimatic events in North Africa during the late Pleistocene and Holocene; such as the Nile floods, high sea level and the formation of sapropels in the Mediterranean. © 2015 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59751
Appears in Collections: 过去全球变化的重建
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作者单位: Geology Department, Faculty of Science, Cairo University, Egypt; Department of Geography, University of Georgia, USA, Athens, GA
Recommended Citation:
Hamdan M.A.,Brook G.A.. Timing and characteristics of Late Pleistocene and Holocene wetter periods in the Eastern Desert and Sinai of Egypt, based on 14C dating and stable isotope analysis of spring tufa deposits[J]. Quaternary Science Reviews,2015-01-01,130