早上新世非洲季风与地中海表层生产力变化的岁差节律-地球科学.PDF

32 3 ——— Vol.32　No.3 2 0 0 7 5 Earth Science—Journal of China University of Geosciences May 　2 0 0 7 黄恩清 , 田军, 2 .同济大学海洋地质国家重点实验室, 上海 200092 2.不来梅大学地质科学系与海洋边缘研究中心, 不来梅D-28359, 德国 :, .Cape Sper- tivento , (5.3～4.8 M a)-. , ., , , C/N , , G.obliquus , .. , . :;;;;. :P732　　　　:000-2383(2007)03-03 3-09　　　　:2006- 0-26 Early Pliocene Precession Rhythm of African Monsoon and Mediterranean Sea Surface Productivity HUANG En-qing , TIAN Jun ,2 .State Key Laboratory of Marine Geology, Tongj i University , Shanghai 200092, China 2.Department of Geosciences and esearch Center of Ocean Margins, University of Bremen, D-28359 Bremen, Germany Abstract:The Profile Cape Spertivento, located in the Calabria peninsula of Italy, is composed of the Early Pliocene (5.3- 4.8 Ma)Mediterranean marl-clay sediments.Based on the former w ork, a more accurate astronomically tuned timescale has been reconstructed for the sequence Cape Spertivento in this paper.Paleoproductivity proxies show that during the Early Pli- ocene, the increases of the Northern Hemisphere summer insolation alw ays concurred with the increases of the organic car- 8 bon MAR, the high C/N ratios, the decreases of the carbonate MAR, and the negative excursions of G.obliquus δO and 3 δC, w hich w ere probably caused by the enhanced rainfall, resulting from the strengthened African summer monsoon.Mo- reover, the st rong African summer monsoon led to the flooding of the Nile River, increasing the discharge of continental nu- trients and fresh water into the Mediterranean Sea.Strong precession and abundant semi-precession cycles are found in the spe