The Earliest Oligocene Glacial Maxmum: Records from ODP Site 1265, South Atlantic
-
摘要: 始新世—渐新世(EO) 过渡期间, 地球由两极无冰的“温室地球”进入到南极有冰的“冰室地球”, 其中以发生在早渐新世初的大冰期事件尤为意义重大.南大西洋ODP1265站氧碳稳定同位素在EO过渡期间发生重大变化, 表明早渐新世全球气温迅速下降, 南极大陆东部首次出现大规模永久性冰盖, 同时全球碳储库发生重大改组, 这一结果与全球其他地区的记录一致.碳酸盐含量、粗组分、浮游有孔虫碎壳率以及碳酸钙软泥的粒度在EO界线附近都发生了突变, 指示了海洋表层生产力的升高、碳酸盐补偿深度(CCD) 的突然加深以及气候快速变冷对生物和碳酸盐沉积的影响.Abstract: The most prominent cooling event of the Cenozoic earth surface during the long-term transition from a non-glaciated planet, or "green-house world", to a polar glaciated planet, or "ice-house world", is the earliest Oligocene glacial maximum (EOGM), immediately following the Eocene-Oligocene (E/O) boundary at about 33.7 Ma. This study analyzed benthic foraminiferal oxygen and carbon isotopes, carbonate content, coarse fraction, planktonic foraminiferal fragmentation, benthic foraminiferal percentage, and carbonate ooze grain size in samples from deep-water Site 1265, Ocean Drilling Program (ODP) Leg 208 on the Walvis Ridge, South Atlantic. The results show that the earliest Oligocene δ18O values represent the magnitude of continental ice sheets on east Antarctica and indicate a large decrease in both surface and deep water temperatures of worldwide oceans during the Eocene-Oligocene transition. Carbonate content, coarse fraction, planktonic foraminiferal fragmentation, benthic foraminiferal percentage and grain size of ODP Site 1265 indicate that carbonate content increases rapidly across the E/O boundary, reflecting the increasing of ocean paleo-productivity, the abrupt deepening in the carbonate compensation depth (CCD) and their impacts on faunas and carbonate deposition.
-
Key words:
- earliest Oligocene glacial maximum /
- South Atlantic /
- ODP site 1265 /
- Eocene /
- Oligocene
-
图 1 ODP1265站始新世—渐新世过渡期的年龄—深度模式(据Shipboard Scientific Party, 2004)
Fig. 1. Age model of the Eocene-Oligocene transition at ODP Site 1265
图 2 ODP1265和DSDP522站氧碳稳定同位素及古温度对比(DSDP522站资料据Zachos et al., 1996, 2001)
Fig. 2. Comparison of oxygen and carbon stable isotopes and estimated paleo-temperatures from ODP Site 1265 and DSDP Site 522
图 3 ODP1265站碳酸盐溶解指标和氧碳稳定同位素对比(磁化率和颜色反射率据Shipboard Scientific Party, 2004)
Fig. 3. Carbonate dissolution proxies and oxygen and carbon stable isotopes of ODP Site 1265
-
Balsam, W.L., Deaton, B.C., Damuth, J.E., 1999. Evaluating optical lightness as a proxy for carbonate content in marine sediments cores. Marine Geology, 161: 141 -153. doi: 10.1016/S0025-3227(99)00037-7 Berger, W. H., 1973. Deep-sea carbonates: Evidence for a coccolith lysocline. Deep Sea Research, 20: 917 -921. https://www.doc88.com/p-98539083930844.html Coxall, H.K., Wilson, P.A., Palike, H., et al., 2005. Rapid stepwise onset of Antarctic glacition and deeper calcite compensation in the Pacific Ocean. Nature, 433(6): 53 -57. https://www.nature.com/articles/nature03135 Department of Marine Geology, Tongji University, 1989. Itroduction to paleoceanography. Tongji University Press, Shanghai(in Chinese). Diester-Haass, L., Robert, C., Chamley, H., 1993. Paleceanographic and paleoclimatic evolution in the Weddell Sea(Antarctica)during the Middle Eocene-Late Oligcene, from coarse sediment fraction and clay mineral dta(ODP Site 689). Marine Geology, 114: 233 -250. doi: 10.1016/0025-3227(93)90030-Y Diester-Haass, L., 1995. Middle Eocene to Early Oligocene paleoceanography of the Antarctic Ocean(Maud Rise, ODP Leg 113, Site 689): Change from a low to high productivity ocean. Palaeogeography, Palaeoclimatolgy, Palaeoecology, 113: 311 -334. doi: 10.1016/0031-0182(95)00067-V Diester-Haass, L., 1996. Late Eocene-Oligocene paleoceanoraphy in the southern Indian Ocean(ODP Site 744). Marine Geology, 130: 99 -119. doi: 10.1016/0025-3227(95)00128-X Diester-Haass, L., Zahn, R., 2001. Paleoproductivity increase at the Eocene-Oligocene climatic transition: ODP/DSDP sites 763 and 592. Palaeogeography, Palaeoclimatolgy, Palaeoecology, 172: 153 -170. doi: 10.1016/S0031-0182(01)00280-2 Diester-Haass, L., Zachos, J. C., 2003. The Eocene-Oligcene transition in the equatorial Atlantic(ODP Site 925): Paleoproductivity increase and positiveδ13 C ecursion. In: Prothero, D. R., Ivany, L.C., Nesbitt, E. A., eds., From greenhouse to icehouse: The marine Eocene-Oligocene transition. Columbia University Press, New York, 397 -416. Elderfield, H., 2002. Carbonate mysteries. Science, 296: 1618 -1621. doi: 10.1126/science.1072079 Emerson, S., Hedges, J.I., 1988. Processes controlling the organic carbon content of open ocean sediments. Paleceanography, 3: 621 -634. doi: 10.1029/PA003i005p00621 Erez, J., Luz, B., 1983. Experimental paleotemperature eqution for planktonic foraminifera. Geochim. Cosmochim. Acta, 47: 1025 -1031. doi: 10.1016/0016-7037(83)90232-6 Jones, A., Kaiteris, P., 1983. A vacuum gasometic technique for rapid and precise analysis of calcium carbonate in sediments and soils. Journal of Sedimentary Petrolgy, 53: 655 -660. doi: 10.1306/212F825B-2B24-11D7-8648000102C1865D Le, J., Shackleton, N.J., 1992. Carbonate dissolution fluctations in the western equatorial Pacific during the Late Quaternary. Paleoceanography, 7: 21 -42. doi: 10.1029/91PA02854 Liu, Z.F., Tuo, S.T., Zhao, Q.H., et al., 2004. Deep sewater earliest Oligocene glacial maxmium in South Alantic. Chinese Science Bulletin, 49(20): 2190 -2197. doi: 10.1007/BF03185787 Mackensen, A., Bickert, T., 1999. Stable isotopes in benthic foraminifera: Proxies for deep and bottom water circultion and new production. In: Fischer, G., Wefer, G., eds., Use of proxies in paleoceanography: Examples from the South Atlantic. Springer-Verlag, Berlin, Hedelberg, 229 -254. Nilsen, E.B., Anderson, L.D., Delaney, M.L., 2003. Paleproductivity, nutrient burial, climate change and carbon cycle in the western equatorial Atlantic across the Ecene/Oligocene boundary. Paleoceanography, 18: doi:10.1029 /2002PA000804. Peterson, L.C., Backman, J., 1990. Late Cenozoic carbonate accumulation and the history of the carbonate compesation depth in the western equatorial Indian Ocean. Proceeding Ocean Drilling Program Scientific Rsults, 115: 467 -507. https://www.researchgate.net/publication/291849159_Late_Cenozoic_Carbonate_Accumulation_and_the_History_of_the_Carbonate_Compensation_Depth_in_the_Western_Equatorial_Indian_Ocean Salamy, K.A., Zachos, J.C., 1999. Latest Eocene-Early Olgocene climate change and southern Ocean fertility: Iferences from sediment accumulation and stable isotope data. Palaeogeography, Palaeoclimatology, Palaeecology, 145: 61 -77. Shipboard Scientific Party, 2004. Leg 208 summary. In: Zchos, J. C., Kroon, D., Blum, P., et al., eds., Proc Ocean Drill Program Init. Repts. 208: College Station TX(Ocean Drilling Program), 1 -112. Tuo, S. T., Liu, Z. F., 2003. Global climate event at the Eocene-Oligocene transition: From greenhouse to ichouse. Advances in Earth Science, 18(5): 691 -696(in Chinese with English abstract). https://en.cnki.com.cn/Article_en/CJFDTotal-DXJZ200305008.htm Wang, P.X., Tian, J., Cheng, X.R., et al., 2003. Exploring cyclic changes of the ocean carbon reservoir. Chinese Science Bulletin, 48(23): 2356 -2548. doi: 10.1360/03wd0155 Zachos, J.C., Stott, L.D., Lohmann, K.C., 1994. Evolution of Early Cenozoic marine temperatures. Paleoceanogrphy, 9(2): 353 -387. doi: 10.1029/93PA03266 Zachos, J. C., Quinn, T. M., Salamy, K. A., 1996. Higresolution(104 years)deep-sea foraminiferal stable istope records of the Eocene-Oligocene climate transition. Paleoceanography, 11: 251 -266. doi: 10.1029/96PA00571 Zachos, J.C., Pagani, M., Sloan, L., et al., 2001. Trends, rhythms, and aberrations in global climate 65 Ma to present. Science, 292: 686 -693. https://pubmed.ncbi.nlm.nih.gov/11326091/ 刘志飞, 拓守廷, 赵泉鸿, 等, 2004. 南大西洋深水渐新世初大冰期事件. 科学通报, 49(17): 1793 -1800. https://www.cnki.com.cn/Article/CJFDTOTAL-KXTB200417020.htm 同济大学海洋地质系, 1989. 古海洋学概论. 上海: 同济大学出版社. 拓守廷, 刘志飞, 2003. 始新世—渐新世界线的全球气候事件: 从"温室"到"冰室". 地球科学进展, 18(5): 691 -696. https://www.cnki.com.cn/Article/CJFDTOTAL-DXJZ200305008.htm 汪品先, 田军, 成鑫荣, 等, 2003. 探索大洋碳储库的演变周期. 科学通报, 48(21): 2216 -2227. https://www.cnki.com.cn/Article/CJFDTOTAL-KXTB200321003.htm