The components of the primary elements in the dune sands for the MGS1 subsection of the Milanggouwan section in the Salawusu River valley, compared with those of modern dune sands, show that they were caused by East A...The components of the primary elements in the dune sands for the MGS1 subsection of the Milanggouwan section in the Salawusu River valley, compared with those of modern dune sands, show that they were caused by East Asian winter monsoon in the Mu Us desert during Holocene. The examined ages for the 11 layers of dune sands, based on the average sedimentary rate, are： 0 to 960, 1350-2240, 2470 to 3530, 4000 to 4180, 4290 to 4350, 4380 to 4760, 5040 to 5920, 6570 to 8270, 9020 to 9700, 9880 to 10160 and 10580 to 11080 a BP, respectively. The climatic events indicated by these dune sands are consistent with those records in the Huguangyan volcanic lake, Zoige peat bog, Hulu cave and Dunde ice core, particularly with the climatic fluctuations of the North Atlantic since 11 000 a BP. Among them, patterns from B0 to B8 correspond to the peak values of 0MD, 2D, 4D, 6D＋8D＋10D, 12D, 14D, 16D, 18D and 20D respectively. It might be caused by the North Atlantic ice age induced by the heat circulation, which strengthened the polar high pressure and Siberian-Mongolian high pressure and further led to the dominance of the winter monsoon over China＇s desert area.展开更多
在国内外研究的基础上,对印太暖池区的沃克环流和厄尔尼诺-南方涛动(ENSO)、热带辐合带(ITCZ)等低纬过程的空间分布和随时间的变化规律及其研究方法进行初步归纳,并指出研究中存在的问题。本文论述了厄尔尼诺-南方涛动变率在全新世早期...在国内外研究的基础上,对印太暖池区的沃克环流和厄尔尼诺-南方涛动(ENSO)、热带辐合带(ITCZ)等低纬过程的空间分布和随时间的变化规律及其研究方法进行初步归纳,并指出研究中存在的问题。本文论述了厄尔尼诺-南方涛动变率在全新世早期及中世纪气候异常期(1 000~700 a BP)的晚期逐渐增强,介绍了热带辐合带在BA暖期(B?llingAller?d Warm Period)和前北方期(pre-Boreal,10.3~9.5 ka BP)的北移,以及在新仙女木事件(Younger Dryas Event,12.5~11.5 ka BP)和北大西洋冷期(距今7.5~5 ka BP)期间的南移。对低纬过程长时间尺度轨道周期的探讨表明,末次冰盛期赤道东太平洋出现了较偏南的热带辐合带锋面系统,甚至在1.65 Ma冰期,热带辐合带也有快速南移的证据。海洋沉积的粒度、黏土矿物、陆源粉尘、元素和同位素、有孔虫分析等研究方法在推测厄尔尼诺-南方涛动和热带辐合带位移中有很好的应用,建议以陆源生态系统对气候的响应为切入点、以孢粉为手段来探讨陆源植被、气候、火灾和海-陆大气环流等低纬过程的变化特征,进而反演沃克环流(或厄尔尼诺-南方涛动)演化和热带辐合带位移的影响。展开更多
Studies of lithology, sedimentary facies and the distribution regularity of SiO2 and Al2O3 contents and Al2O3/SiO2 ratio allow us to divide the Upper Pleistocene-Holocene Series represented by the MUanggouwan section ...Studies of lithology, sedimentary facies and the distribution regularity of SiO2 and Al2O3 contents and Al2O3/SiO2 ratio allow us to divide the Upper Pleistocene-Holocene Series represented by the MUanggouwan section in China＇s Salawnsu River valley into six segments： MGS1, MGS2, MGS3, MGS4, MGS5 and MGS6. The boundary ages for MGS1 （the Dishaogouwan and Dagouwan Formations）, MGS2 （the upper Chengchuan Formation）, MGS3 （the middle Chengchuan Formation）, MGS4 （the lower Chengchuan Formation）, MGS5 （most strata of the Salawusu Formation） and MGS6 （the bottom of the Salawusu Formation and the top of the Lishi Formation） correspond to those of MIS1, MIS2, MIS3, MIS4, MISS and MIS6, respectively, from deep sea sediments or continental glaciers. MGS5 can be subdivided into five subsegments （MGS5a, MGS5b, MGS5c, MGS5d and MGS5e） and the boundary ages of these subsegments correspond to those of MISSa, MISSb, MIS5c, MIS5d and MIS5e, respectively. Based on the paleoenvironment and paleoecology indicated by the primary chemical elements, fossil vertebrates, mollusks and pollen grains, we hypothesize that MGS1, MGS2, MGS3, MGS4, MGS5 and MGS6 and the subsegments of MGS5 match the corresponding stages for oxygen isotopes in the deep sea sediments and continental glaciers, and the substages of MIS5 in terms of climatic characters, further explaining the phenomena that determined the formation of the late Quaternary strata and the paleontology of the Salawusu River valley. These phenomena relate to fluctuations in the global climate （and particularly in the East Asian monsoon） during the glacial and interglacial periods.展开更多
火事件的发生与气候变化以及植被变化密切相关,系统性地研究全新世火活动的时空演化规律,可以更清晰地理解火活动机制与区域性气候、植物变化的关联,同时有助于预测未来火的演化趋势。为了解安达曼海周边地区火灾活动的演化以及可能的...火事件的发生与气候变化以及植被变化密切相关,系统性地研究全新世火活动的时空演化规律,可以更清晰地理解火活动机制与区域性气候、植物变化的关联,同时有助于预测未来火的演化趋势。为了解安达曼海周边地区火灾活动的演化以及可能的驱动因素,以安达曼海南部的海洋钻孔ADM-C1为研究材料,对其全新世以来的炭屑记录进行深入分析,并综合安达曼海周边地区其余的5个炭屑记录,重建了全新世以来安达曼海周边地区火灾活动的演变过程。研究表明,尽管点火、火灾天气和植被组成在各地不尽相同,导致火灾发生频率在区域和地方范围有所不同,但在广泛的气候变化背景下,全新世安达曼海周边各地的火事件发生频率变化具有广泛同步性。全新世安达曼海周边的火灾活动发生频率受到区域性植被和降水变化影响,并最终受控于印度夏季风强度的变化。与末次冰消期相比,12.0~9.0 ka BP安达曼海周边区域火灾活动的发生频率呈下降趋势,反映了印度夏季风降水逐步增加以及木本植物含量逐渐上升的区域环境;9.0~5.0 ka BP较低的区域火灾活动发生频率同时受到较高的印度夏季风降水量和区域木本植物含量的制约;5.0 ka BP后高频的区域火灾活动更多反映了印度夏季风降水的降低。此外,研究结果还表明全新世安达曼海周边区域火灾活动发生频率与厄尔尼诺—南方涛动强度、印度洋偶极子位相和热带辐合带位置的变化相关。展开更多
The paleoenvironment indicated by the geochronology,major oxides——SiO2,Al2O3 and TOFE(Fe2O3 + FeO),and CIA(Chemical Index of Alteration) value of the red earth and brown-yellow silt primarily characterized by the Li...The paleoenvironment indicated by the geochronology,major oxides——SiO2,Al2O3 and TOFE(Fe2O3 + FeO),and CIA(Chemical Index of Alteration) value of the red earth and brown-yellow silt primarily characterized by the Linjiang stratigraphic section,based on the geological investigation of Late Quaternary along the river banks of northeastern part of China's Guangdong Province,south to the Nanling Mountains,allow us to hypothesize that the red earth on the first terrace in northeastern part of Guangdong belongs to reticulated red clay developed in a hot-wet environment of the last interglacial period(132―73 ka BP),similar to the monsoon environment in the northern margin of modern tropical zone,while the overlying brown-yellow silt layer mainly accumulated in a monsoon environment of warm temperate zone in the last glacial period(73―11 ka BP),with the aeolian sand LJ3 representing an extreme period of worsening climate.Such a hypothesis corresponds well with predecessors' research on the paleoenvironment indicated by abundant fossils in both south and east to the Nanling Mountains.Hence,it follows that the bioclimatic zone did experience a large and rapid vicissitude in northeastern part of China's Guangdong Province,and even in the full extent of the region south to the Nanling Mountains from the last interglacial period to the last glacial period,with the red earth being replaced by the brown-yellow silty sediment,and even maybe with the Ailuropoda-Stegodon Fauna being replaced by the Penghu Fauna.This study may provide an important geological demonstration for the environmental response to global change in China's low latitudes on a 10 ka scale.展开更多
基金National Basic Research Program of China, No.2004CB720206 National Natural Science Foundation of China, No.40772118+1 种基金 No.49971009 Knowledge Innovation Project of CAS, No.KZCX2-SW-118
文摘The components of the primary elements in the dune sands for the MGS1 subsection of the Milanggouwan section in the Salawusu River valley, compared with those of modern dune sands, show that they were caused by East Asian winter monsoon in the Mu Us desert during Holocene. The examined ages for the 11 layers of dune sands, based on the average sedimentary rate, are： 0 to 960, 1350-2240, 2470 to 3530, 4000 to 4180, 4290 to 4350, 4380 to 4760, 5040 to 5920, 6570 to 8270, 9020 to 9700, 9880 to 10160 and 10580 to 11080 a BP, respectively. The climatic events indicated by these dune sands are consistent with those records in the Huguangyan volcanic lake, Zoige peat bog, Hulu cave and Dunde ice core, particularly with the climatic fluctuations of the North Atlantic since 11 000 a BP. Among them, patterns from B0 to B8 correspond to the peak values of 0MD, 2D, 4D, 6D＋8D＋10D, 12D, 14D, 16D, 18D and 20D respectively. It might be caused by the North Atlantic ice age induced by the heat circulation, which strengthened the polar high pressure and Siberian-Mongolian high pressure and further led to the dominance of the winter monsoon over China＇s desert area.
文摘在国内外研究的基础上,对印太暖池区的沃克环流和厄尔尼诺-南方涛动(ENSO)、热带辐合带(ITCZ)等低纬过程的空间分布和随时间的变化规律及其研究方法进行初步归纳,并指出研究中存在的问题。本文论述了厄尔尼诺-南方涛动变率在全新世早期及中世纪气候异常期(1 000~700 a BP)的晚期逐渐增强,介绍了热带辐合带在BA暖期(B?llingAller?d Warm Period)和前北方期(pre-Boreal,10.3~9.5 ka BP)的北移,以及在新仙女木事件(Younger Dryas Event,12.5~11.5 ka BP)和北大西洋冷期(距今7.5~5 ka BP)期间的南移。对低纬过程长时间尺度轨道周期的探讨表明,末次冰盛期赤道东太平洋出现了较偏南的热带辐合带锋面系统,甚至在1.65 Ma冰期,热带辐合带也有快速南移的证据。海洋沉积的粒度、黏土矿物、陆源粉尘、元素和同位素、有孔虫分析等研究方法在推测厄尔尼诺-南方涛动和热带辐合带位移中有很好的应用,建议以陆源生态系统对气候的响应为切入点、以孢粉为手段来探讨陆源植被、气候、火灾和海-陆大气环流等低纬过程的变化特征,进而反演沃克环流(或厄尔尼诺-南方涛动)演化和热带辐合带位移的影响。
基金This study was supported by the National Basic Research Program of China （No. 2004CB720206） the National Natural Science Foundation of China （No. 49971009）the RGC （HKU 7243/04H） Grant of the HKSAR and the Chinese Academy of Sciences （No. KZCX2-SW-118）
文摘Studies of lithology, sedimentary facies and the distribution regularity of SiO2 and Al2O3 contents and Al2O3/SiO2 ratio allow us to divide the Upper Pleistocene-Holocene Series represented by the MUanggouwan section in China＇s Salawnsu River valley into six segments： MGS1, MGS2, MGS3, MGS4, MGS5 and MGS6. The boundary ages for MGS1 （the Dishaogouwan and Dagouwan Formations）, MGS2 （the upper Chengchuan Formation）, MGS3 （the middle Chengchuan Formation）, MGS4 （the lower Chengchuan Formation）, MGS5 （most strata of the Salawusu Formation） and MGS6 （the bottom of the Salawusu Formation and the top of the Lishi Formation） correspond to those of MIS1, MIS2, MIS3, MIS4, MISS and MIS6, respectively, from deep sea sediments or continental glaciers. MGS5 can be subdivided into five subsegments （MGS5a, MGS5b, MGS5c, MGS5d and MGS5e） and the boundary ages of these subsegments correspond to those of MISSa, MISSb, MIS5c, MIS5d and MIS5e, respectively. Based on the paleoenvironment and paleoecology indicated by the primary chemical elements, fossil vertebrates, mollusks and pollen grains, we hypothesize that MGS1, MGS2, MGS3, MGS4, MGS5 and MGS6 and the subsegments of MGS5 match the corresponding stages for oxygen isotopes in the deep sea sediments and continental glaciers, and the substages of MIS5 in terms of climatic characters, further explaining the phenomena that determined the formation of the late Quaternary strata and the paleontology of the Salawusu River valley. These phenomena relate to fluctuations in the global climate （and particularly in the East Asian monsoon） during the glacial and interglacial periods.
文摘火事件的发生与气候变化以及植被变化密切相关,系统性地研究全新世火活动的时空演化规律,可以更清晰地理解火活动机制与区域性气候、植物变化的关联,同时有助于预测未来火的演化趋势。为了解安达曼海周边地区火灾活动的演化以及可能的驱动因素,以安达曼海南部的海洋钻孔ADM-C1为研究材料,对其全新世以来的炭屑记录进行深入分析,并综合安达曼海周边地区其余的5个炭屑记录,重建了全新世以来安达曼海周边地区火灾活动的演变过程。研究表明,尽管点火、火灾天气和植被组成在各地不尽相同,导致火灾发生频率在区域和地方范围有所不同,但在广泛的气候变化背景下,全新世安达曼海周边各地的火事件发生频率变化具有广泛同步性。全新世安达曼海周边的火灾活动发生频率受到区域性植被和降水变化影响,并最终受控于印度夏季风强度的变化。与末次冰消期相比,12.0~9.0 ka BP安达曼海周边区域火灾活动的发生频率呈下降趋势,反映了印度夏季风降水逐步增加以及木本植物含量逐渐上升的区域环境;9.0~5.0 ka BP较低的区域火灾活动发生频率同时受到较高的印度夏季风降水量和区域木本植物含量的制约;5.0 ka BP后高频的区域火灾活动更多反映了印度夏季风降水的降低。此外,研究结果还表明全新世安达曼海周边区域火灾活动发生频率与厄尔尼诺—南方涛动强度、印度洋偶极子位相和热带辐合带位置的变化相关。
基金Supported by National Natural Science Foundation of China (Grant No.40471139)National Basic Research Program of China (Grant No.2004CB720206)+1 种基金the Special Fund of Scientific Research for Doctoral Subjects of Chinese Universities (Grant No. 20070574005)the RGC Grant of the HKSAR (HKU7243/04H)
文摘The paleoenvironment indicated by the geochronology,major oxides——SiO2,Al2O3 and TOFE(Fe2O3 + FeO),and CIA(Chemical Index of Alteration) value of the red earth and brown-yellow silt primarily characterized by the Linjiang stratigraphic section,based on the geological investigation of Late Quaternary along the river banks of northeastern part of China's Guangdong Province,south to the Nanling Mountains,allow us to hypothesize that the red earth on the first terrace in northeastern part of Guangdong belongs to reticulated red clay developed in a hot-wet environment of the last interglacial period(132―73 ka BP),similar to the monsoon environment in the northern margin of modern tropical zone,while the overlying brown-yellow silt layer mainly accumulated in a monsoon environment of warm temperate zone in the last glacial period(73―11 ka BP),with the aeolian sand LJ3 representing an extreme period of worsening climate.Such a hypothesis corresponds well with predecessors' research on the paleoenvironment indicated by abundant fossils in both south and east to the Nanling Mountains.Hence,it follows that the bioclimatic zone did experience a large and rapid vicissitude in northeastern part of China's Guangdong Province,and even in the full extent of the region south to the Nanling Mountains from the last interglacial period to the last glacial period,with the red earth being replaced by the brown-yellow silty sediment,and even maybe with the Ailuropoda-Stegodon Fauna being replaced by the Penghu Fauna.This study may provide an important geological demonstration for the environmental response to global change in China's low latitudes on a 10 ka scale.
