南沙群岛南永2井沉积层“红色事件”和“黑色事件”的成因探讨
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摘要
南沙群岛南永2井的红色沉积层和黑色沉积层标志着两次异常事件,简称为“红色事件”和“黑色事件”。这两个特殊沉积层的主要特征是磁化率为正值、锰铝(黑色沉积)和铁铝(红色沉积)含量高。关于它们的成因主要有两种观点:一种是火山喷发或地震活动,另一种是气候突变。将红色沉积层和黑色沉积层与南海其它珊瑚礁钻井资料、南海及其周缘火山活动和深海沉积中的微玻陨石进行详细对比,并综合分析几种成因的可能性大小。“红色事件”和“黑色事件”在南海其它珊瑚礁钻井中的反映不明显或无反映,表明两事件的影响范围很有限。尽管南海周缘的一些火山活动期次、全球气候变化的一些代用指标和深海沉积中的微玻陨石层在时间上与“红”、“黑”两事件有较好的对比,成岩作用也能使某些沉积层位形成铁富集或锰富集,但综合考虑各个因素可以排除周缘火山喷发、气候突变、撞击事件及成岩作用等4种成因。火山或地震活动引起的铁或锰热泉上涌可以对“红”、“黑”两事件作出较好的解释,是可能性较大的成因。
The second drill core at the Yongshu Reef(core Nanyong-2) of Nansha Islands in the South China Sea is located at 9°33′N,112°52′E.It has been drilled down to 413.69 m,penetrating through the whole Quaternary into the upper Miocene. In this core,red-colored and black-colored sedimentary rocks are found at the depths of 195.96—196.26m and 96.59—99.69m,respectively.These unusual rocks are dominantly characterized with positive susceptibility and very rich in Mn-Al(black-colored sediments) and Fe-Al(red-colored sediments).They imply two abnormal events suddenly taking place during the accumulation of coral reefs,which are called "Red Event" and "Black Event" for short,respectively.At present,two explanations for their formations have been proposed—volcanic activity and sudden climate change.We try to correlate detailedly these unusual rocks with other reef drill cores,microtektites from deep-sea sediments and volcanic activities occurring in the South China Sea and its vicinity.Further more,all possible origins of the "Red Event" and "Black Event" have been systematically analyzed.These two events have only little reflection in core Nanyong-1,which is only 100m away from core Nanyong-2,and no reflection in other reef cores.That means the coverage of these two events is very limited.Therefore,volcanic activity and sudden climate change seem unlikely to be the origins of the "Red Event" and "Black Event".Although the red-colored and black-colored sediments can be correlated well with the microtektites from deep-sea sediments in age,they are greatly different in distribution,shape,configuration and other characteristics.Accordingly,celestial body impacts as the origins of these two events also should be eliminated.Diagenesis may lead to the concentration of Fe or Mn in certain sedimentary layers;however,the properties of such concentration are quite different from those of the studied layers.In the end,we come to the conclusion based on available data that Fe(Fe-rich hydrothermal fluid) and Mn plumes(Mn-rich hydrothermal fluid) are more favorable for explaining the formation causes of the red-colored and black-colored sedimentary rocks in core Nanyong-2.
The second drill core at the Yongshu Reef(core Nanyong-2) of Nansha Islands in the South China Sea is located at 9°33′N,112°52′E.It has been drilled down to 413.69 m,penetrating through the whole Quaternary into the upper Miocene. In this core,red-colored and black-colored sedimentary rocks are found at the depths of 195.96—196.26m and 96.59—99.69m,respectively.These unusual rocks are dominantly characterized with positive susceptibility and very rich in Mn-Al(black-colored sediments) and Fe-Al(red-colored sediments).They imply two abnormal events suddenly taking place during the accumulation of coral reefs,which are called "Red Event" and "Black Event" for short,respectively.At present,two explanations for their formations have been proposed—volcanic activity and sudden climate change.We try to correlate detailedly these unusual rocks with other reef drill cores,microtektites from deep-sea sediments and volcanic activities occurring in the South China Sea and its vicinity.Further more,all possible origins of the "Red Event" and "Black Event" have been systematically analyzed.These two events have only little reflection in core Nanyong-1,which is only 100m away from core Nanyong-2,and no reflection in other reef cores.That means the coverage of these two events is very limited.Therefore,volcanic activity and sudden climate change seem unlikely to be the origins of the "Red Event" and "Black Event".Although the red-colored and black-colored sediments can be correlated well with the microtektites from deep-sea sediments in age,they are greatly different in distribution,shape,configuration and other characteristics.Accordingly,celestial body impacts as the origins of these two events also should be eliminated.Diagenesis may lead to the concentration of Fe or Mn in certain sedimentary layers;however,the properties of such concentration are quite different from those of the studied layers.In the end,we come to the conclusion based on available data that Fe(Fe-rich hydrothermal fluid) and Mn plumes(Mn-rich hydrothermal fluid) are more favorable for explaining the formation causes of the red-colored and black-colored sedimentary rocks in core Nanyong-2.
引文
[1]朱袁智,沙庆安,郭丽芬,等.南沙群岛永暑礁新生代珊瑚礁地质[M].北京:科学出版社,1997:1—123.
[2]颜文,汤贤赞,陈忠,等.南永2井珊瑚礁“红色与黑色沉积夹层”的成因及环境意义初探[J].科学通报,2001,46(17):1476—1480.
[3]胡修棉,黄永健.与“南永2井珊瑚礁‘红色与黑色沉积夹层’的成因及环境意义初探”商榷[J].科学通报,2002,47(4):318—319.
[4]颜文.对胡修棉等人的答复[J].科学通报,2002,47(4):319—320.
[5]中国科学院南沙综合科学考察队.南沙群岛永暑礁第四纪珊瑚礁地质[M].北京:海洋出版社,1992:47—143.
[6]张明书.西沙珊瑚礁区的第四纪事件[J].第四纪研究,1991,(2):165—177.
[7]张明书,刘健,周墨清.西琛一井礁序列锶同位素组分变化[J].海洋地质与第四纪地质,1995,15(1):125—130.
[8]张明书,周墨清,刘健.西沙礁序列的磁性地层学研究[J].海洋地质与第四纪地质,1996,16(3):61—65.
[9]张明书.西沙西永1井礁相第四纪地层的划分[J].海洋地质与第四纪地质,1990,10(2):57—64.
[10]阎贫,刘海龄.南海及其周缘中新生代火山活动时空特征与南海的形成模式[J].热带海洋学报,2005,24(2):33—41.
[11]黄镇国,蔡福祥,韩中元,等.雷琼第四纪火山[M].北京:科学出版社,1993:179—220.
[12]HO K S,CHEN J C,JUANG W S.Geochronology and ge-ochemistry of late Cenozoic basalts from the Leiqiong area,southern China[J].Journal of Asian Earth Sciences,2000,18(3):307—324.
[13]邹和平.南海北部—台湾海峡及邻区新生代火山活动时序与分布[J].华东地质学院学报,1993,16(1):24—31.
[14]王汝建.南沙海区更新世以来的火山灰及其地质意义[J].海洋地质与第四纪地质,2000,20(1):51—56.
[15]彭汉昌,丛友滋,庄世杰,等.太平洋岩芯微玻璃陨石层的发现和与地磁事件及地磁倒转的联系[J].科学通报,1992,37(2):150—153.
[16]李志珍.南海中部深海沉积物中的宇宙尘[J].沉积学报,1989,7(3):31—38.
[17]李志珍,张富元.南海深海铁锰微粒的元素地球化学特征[J].海洋通报,1990,9(6):41—50.
[18]赵泉鸿,翦知湣,李保华,等.南沙深海沉积中的中更新世微玻陨石[J].中国科学(D辑),1999,29(1):45—49.
[19]韦刚健,梁细荣,李献华,等.ODP1144站钻孔沉积物中微玻璃陨石的元素地球化学特征[J].地球化学,2002,31(1):35—42.
[20]张蕾,刘建忠,赵泉鸿,等.南海ODP1144孔微玻璃陨石物理化学性质及母源物质的复杂性[J].地质地球化学,2003,31(2):65—72.
[21]李霞,赵泉鸿,黄宝琦,等.中更新世撞击事件年龄的高分辨率估算[J].海洋地质与第四纪地质,2004,24(2):73—77.
[22]杨育标.南海中部海区表层沉积物中火山碎屑的初步研究[J].南海研究与开发,1989,(3):48—55.
[23]杨育标,范时清.南海深海晚第四纪火山沉积及其起源探讨[J].热带海洋,1990,9(1):52—60.
[24]王慧中,周福根,翦知湣.中沙台缘碳酸盐软泥中的火山碎屑及其古环境意义[C]//南海晚第四纪古海洋学研究.青岛:青岛海洋大学出版社,1992:42—55.
[25]谈丽芳.南海火山玻璃的初步研究[J].南海地质研究,1991,(3):158—171.
[26]李志珍.南海深海表层沉积物中的火山碎屑矿物及火山作用[J].海洋学报,1989,11(2):176—184.
[27]时振波,林晓彤,杨群慧,等.南海东部晚更新世以来的火山沉积特征[J].中国海洋大学学报,2004,34(6):1063—1068.
[28]邱传珠.南海铁锰沉积物和火山碎屑沉积物特征及其分布规律的研究[J].热带海洋,1983,2(4):269—277.
[29]郭丽芬,陈婉颜,陈丽虹.南沙群岛永暑礁区近百万年来的古气候变化———南永1井的锰含量分析[J].热带海洋,1993,12(4):39—46.
[30]SHEN G T,CAMPBELL R B,DUNBAR R B,et al.Pa-leochemistry of manganese in corals from the GalapagosIslands[J].Coral Reef,1991,10(2):91—100.
[31]张兴茂,翁焕新.南海东北部陆坡铁锰沉积记录对环境变化的指示意义[J].海洋学报,2005,27(1):93—100.
[32]李延,宋金明,朱仲斌.辽东湾海底铁、锰的氧化还原过程及化学成岩作用[J].海洋与湖沼,1991,22(5):451—457.
[33]BOGDANOV Y A,LISITZIN A P,BINNS R A,et al.Low-temperature hydrothermal deposits of Franklin Sea-mount,Woodlark Basin,Papua New Guinea[J].MarineGeology,1997,142:99—117.
[34]CANET C,PROL-LEDESMA R M,PROENZA J A,et al.Mn-Ba-Hg mineralization at shallow submarine hydrother-mal vents in Bahía Concepción,Baja California Sur,Mexico[J].Chemical Geology,2005,224:96—112.
[35]DORIS S,PETER S,JEAN L C,et al.Manganese,meth-ane,iron,zinc,and nickel anomalies in hydrothermalplumes from Teahitia and Macdonald volcanoes[J].Geochimica et Cosmochimica Acta,1992,56(10):3 693—3 704.
[36]JOHNSON K S,CHILDRESS J J,HESSLER R R,et al.Chemical and biological interactions in the Rose Garden hy-drothermal vent field,Galapagos spreading center[J].DeepSea Research Part A,1988,35(10/11):1 723—1 744.
[2]颜文,汤贤赞,陈忠,等.南永2井珊瑚礁“红色与黑色沉积夹层”的成因及环境意义初探[J].科学通报,2001,46(17):1476—1480.
[3]胡修棉,黄永健.与“南永2井珊瑚礁‘红色与黑色沉积夹层’的成因及环境意义初探”商榷[J].科学通报,2002,47(4):318—319.
[4]颜文.对胡修棉等人的答复[J].科学通报,2002,47(4):319—320.
[5]中国科学院南沙综合科学考察队.南沙群岛永暑礁第四纪珊瑚礁地质[M].北京:海洋出版社,1992:47—143.
[6]张明书.西沙珊瑚礁区的第四纪事件[J].第四纪研究,1991,(2):165—177.
[7]张明书,刘健,周墨清.西琛一井礁序列锶同位素组分变化[J].海洋地质与第四纪地质,1995,15(1):125—130.
[8]张明书,周墨清,刘健.西沙礁序列的磁性地层学研究[J].海洋地质与第四纪地质,1996,16(3):61—65.
[9]张明书.西沙西永1井礁相第四纪地层的划分[J].海洋地质与第四纪地质,1990,10(2):57—64.
[10]阎贫,刘海龄.南海及其周缘中新生代火山活动时空特征与南海的形成模式[J].热带海洋学报,2005,24(2):33—41.
[11]黄镇国,蔡福祥,韩中元,等.雷琼第四纪火山[M].北京:科学出版社,1993:179—220.
[12]HO K S,CHEN J C,JUANG W S.Geochronology and ge-ochemistry of late Cenozoic basalts from the Leiqiong area,southern China[J].Journal of Asian Earth Sciences,2000,18(3):307—324.
[13]邹和平.南海北部—台湾海峡及邻区新生代火山活动时序与分布[J].华东地质学院学报,1993,16(1):24—31.
[14]王汝建.南沙海区更新世以来的火山灰及其地质意义[J].海洋地质与第四纪地质,2000,20(1):51—56.
[15]彭汉昌,丛友滋,庄世杰,等.太平洋岩芯微玻璃陨石层的发现和与地磁事件及地磁倒转的联系[J].科学通报,1992,37(2):150—153.
[16]李志珍.南海中部深海沉积物中的宇宙尘[J].沉积学报,1989,7(3):31—38.
[17]李志珍,张富元.南海深海铁锰微粒的元素地球化学特征[J].海洋通报,1990,9(6):41—50.
[18]赵泉鸿,翦知湣,李保华,等.南沙深海沉积中的中更新世微玻陨石[J].中国科学(D辑),1999,29(1):45—49.
[19]韦刚健,梁细荣,李献华,等.ODP1144站钻孔沉积物中微玻璃陨石的元素地球化学特征[J].地球化学,2002,31(1):35—42.
[20]张蕾,刘建忠,赵泉鸿,等.南海ODP1144孔微玻璃陨石物理化学性质及母源物质的复杂性[J].地质地球化学,2003,31(2):65—72.
[21]李霞,赵泉鸿,黄宝琦,等.中更新世撞击事件年龄的高分辨率估算[J].海洋地质与第四纪地质,2004,24(2):73—77.
[22]杨育标.南海中部海区表层沉积物中火山碎屑的初步研究[J].南海研究与开发,1989,(3):48—55.
[23]杨育标,范时清.南海深海晚第四纪火山沉积及其起源探讨[J].热带海洋,1990,9(1):52—60.
[24]王慧中,周福根,翦知湣.中沙台缘碳酸盐软泥中的火山碎屑及其古环境意义[C]//南海晚第四纪古海洋学研究.青岛:青岛海洋大学出版社,1992:42—55.
[25]谈丽芳.南海火山玻璃的初步研究[J].南海地质研究,1991,(3):158—171.
[26]李志珍.南海深海表层沉积物中的火山碎屑矿物及火山作用[J].海洋学报,1989,11(2):176—184.
[27]时振波,林晓彤,杨群慧,等.南海东部晚更新世以来的火山沉积特征[J].中国海洋大学学报,2004,34(6):1063—1068.
[28]邱传珠.南海铁锰沉积物和火山碎屑沉积物特征及其分布规律的研究[J].热带海洋,1983,2(4):269—277.
[29]郭丽芬,陈婉颜,陈丽虹.南沙群岛永暑礁区近百万年来的古气候变化———南永1井的锰含量分析[J].热带海洋,1993,12(4):39—46.
[30]SHEN G T,CAMPBELL R B,DUNBAR R B,et al.Pa-leochemistry of manganese in corals from the GalapagosIslands[J].Coral Reef,1991,10(2):91—100.
[31]张兴茂,翁焕新.南海东北部陆坡铁锰沉积记录对环境变化的指示意义[J].海洋学报,2005,27(1):93—100.
[32]李延,宋金明,朱仲斌.辽东湾海底铁、锰的氧化还原过程及化学成岩作用[J].海洋与湖沼,1991,22(5):451—457.
[33]BOGDANOV Y A,LISITZIN A P,BINNS R A,et al.Low-temperature hydrothermal deposits of Franklin Sea-mount,Woodlark Basin,Papua New Guinea[J].MarineGeology,1997,142:99—117.
[34]CANET C,PROL-LEDESMA R M,PROENZA J A,et al.Mn-Ba-Hg mineralization at shallow submarine hydrother-mal vents in Bahía Concepción,Baja California Sur,Mexico[J].Chemical Geology,2005,224:96—112.
[35]DORIS S,PETER S,JEAN L C,et al.Manganese,meth-ane,iron,zinc,and nickel anomalies in hydrothermalplumes from Teahitia and Macdonald volcanoes[J].Geochimica et Cosmochimica Acta,1992,56(10):3 693—3 704.
[36]JOHNSON K S,CHILDRESS J J,HESSLER R R,et al.Chemical and biological interactions in the Rose Garden hy-drothermal vent field,Galapagos spreading center[J].DeepSea Research Part A,1988,35(10/11):1 723—1 744.
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