Plioceneâ€“Pleistocene climate of the northern margin of Saharanâ€“Arabian Desert recorded in speleothems from the Negev Desert, Israel
- Permanent Link:
- Plioceneâ€“Pleistocene climate of the northern margin of Saharanâ€“Arabian Desert recorded in speleothems from the Negev Desert, Israel
- Series Title:
- Earth and Planetary Science Letters
- Vaks, A.
Cliff, R. A.
- Publication Date:
- Subjects / Keywords:
- Speleothems ( local )
Negev Desert ( local )
Paleoclimate ( local )
Uâ€“Pb Chronology ( local )
Pliocene ( local )
Pleistocene ( local )
- serial ( sobekcm )
- The Middleâ€“Late Pliocene climate was 2â€“3 °C warmer than today, but with similar levels of atmospheric CO2. This period reflects climate conditions expected in the near future, and is therefore an important target for current data-modeling studies. This study reconstructs the Plioceneâ€“Quaternary evolution of arid conditions on the northern margin of the Saharanâ€“Arabian desert, using radiometrically (Uâ€“Pb) dated periods of speleothem deposition from three caves of the Negev Desert, Israel. Speleothem growth started between âˆ¼3.75 and âˆ¼3 Ma, at the end of the first significant tectonic uplift of the western shoulder of the Dead Sea Rift. Major speleothem deposition, indicating wet conditions, occurred during the Pliocene around âˆ¼3.1 Ma, with subsequent aridity during the last 3 Myr, punctuated by short wet episodes â€“ the Pleistocene Negev Humid Periods (NHP). The oldest dated NHP occurred between âˆ¼1.7 and âˆ¼1.25 Ma, and other short humid episodes continued intermittently later. Speleothem Î´18O values (âˆ’6.9â€° to âˆ’11.2â€°) show that the humid episodes were associated with periods of low global ice volume and warm temperatures. After correction for rainfall Î´18O changes associated with ice volume and temperature effects, the observed relative constancy of speleothem Î´18O values from Pliocene to Late Pleistocene indicates rainfall was from a common source, most probably the eastern Mediterranean Sea. The humid Pliocene conditions could be generated by more southerly position of the Mediterranean coast (allowing the access of Mediterranean precipitation to the Negev), as well as by warmer Atlantic Sea Surface Temperatures, that weakened the Azores High Pressure Cell. Maximum amounts of precipitation were 500â€“600 mm/a during the Pliocene and >300 mm/a during Pleistocene NHP. The Pliocene and the earliest Pleistocene NHP are associated with formation of lakes in the Negev. Low 87Sr/86Sr ratios of âˆ¼0.7078 in the Pliocene speleothems are indicative of low dust supply, low water residence time in the vadose zone and relatively hig
- Original Version:
- Earth and Planetary Science Letters, Vol. 368 (2013-04-15).
- Source Institution:
- University of South Florida Library
- Holding Location:
- University of South Florida
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- This object is protected by copyright, and is made available here for research and educational purposes. Permission to reuse, publish, or reproduce the object beyond the bounds of Fair Use or other exemptions to copyright law must be obtained from the copyright holder.
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