Pollen grains deposited in marine sediments are transported from land to sea by wind or surface water flows.We analyzed pollen collected from the air and seawater from the coast of the Yellow Sea near China and into t...Pollen grains deposited in marine sediments are transported from land to sea by wind or surface water flows.We analyzed pollen collected from the air and seawater from the coast of the Yellow Sea near China and into the western Pacific Ocean between December 2008 and January 2009 during the cruise "KX08-973".Results showed that abundant pollen grains of Artemisia and Chenopodiaceae were probably transported to the continental shelf of the East China Sea,the East Philippine Sea and the equatorial regions of the Pacific Ocean by the winter monsoon.Some pollen may have even traveled over 2000 km from the East Asia continent to the tropical Pacific Ocean.However,a gradual decline of temperate components and an increase in tropical components was observed towards the tropical regions.Fern spores were rare in the air samples,but much more abundant in seawater samples,even though they were collected in nearly the same areas,which indicates that most fern spores were carried to the ocean by flowing water.These results suggest that the winter monsoon may be the major pollen carrier and transporter in the study area during winter.展开更多
Aeolian dust, a primary terrigenous component of ocean sediments, has been widely used to reconstruct the paleoclimatic evolution because its transported distance, grain size and concentration are sensitive to climate...Aeolian dust, a primary terrigenous component of ocean sediments, has been widely used to reconstruct the paleoclimatic evolution because its transported distance, grain size and concentration are sensitive to climate changes. To further characterize the aeolian dust, the deposits at site Ocean Drilling Program (ODP) 882A in northwestern Pacific Ocean are divided into four grain-size fractions (<8, 8-16, 16-64, >64 μm) using the gravitative differentiation method. Detailed rock magnetism results show that magnetite and hematite are dominant magnetic minerals for the dust components. In addition, the aeolian dust (<8 μm) represented by the concentration of magnetic minerals increases sharply at 2.73 Ma, which corresponds to the onset of major glaciation in the Northern Hemisphere. In contrast, the ice-rafted detritus (IRD) (>64 μm) contributes little to the magnetic enhancement of the sediments at 2.73 Ma. These new results greatly improve our understanding of paleoenvironmental evolution during late Pliocene-early Pleistocene in this area.展开更多
基金supported by National Basic Research Program of China (Grant No. 2007CB815900)National Natural Science Foundation of China (Grant No. 40771072)the Discretionary Foundation of State Key Laboratory of Marine Geology,Tongji University (Grant No. MG20080207)
文摘Pollen grains deposited in marine sediments are transported from land to sea by wind or surface water flows.We analyzed pollen collected from the air and seawater from the coast of the Yellow Sea near China and into the western Pacific Ocean between December 2008 and January 2009 during the cruise "KX08-973".Results showed that abundant pollen grains of Artemisia and Chenopodiaceae were probably transported to the continental shelf of the East China Sea,the East Philippine Sea and the equatorial regions of the Pacific Ocean by the winter monsoon.Some pollen may have even traveled over 2000 km from the East Asia continent to the tropical Pacific Ocean.However,a gradual decline of temperate components and an increase in tropical components was observed towards the tropical regions.Fern spores were rare in the air samples,but much more abundant in seawater samples,even though they were collected in nearly the same areas,which indicates that most fern spores were carried to the ocean by flowing water.These results suggest that the winter monsoon may be the major pollen carrier and transporter in the study area during winter.
基金supported by National Natural Science Foundation of China (Grants Nos. 40974036, 41025013 and 40821091)the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘Aeolian dust, a primary terrigenous component of ocean sediments, has been widely used to reconstruct the paleoclimatic evolution because its transported distance, grain size and concentration are sensitive to climate changes. To further characterize the aeolian dust, the deposits at site Ocean Drilling Program (ODP) 882A in northwestern Pacific Ocean are divided into four grain-size fractions (<8, 8-16, 16-64, >64 μm) using the gravitative differentiation method. Detailed rock magnetism results show that magnetite and hematite are dominant magnetic minerals for the dust components. In addition, the aeolian dust (<8 μm) represented by the concentration of magnetic minerals increases sharply at 2.73 Ma, which corresponds to the onset of major glaciation in the Northern Hemisphere. In contrast, the ice-rafted detritus (IRD) (>64 μm) contributes little to the magnetic enhancement of the sediments at 2.73 Ma. These new results greatly improve our understanding of paleoenvironmental evolution during late Pliocene-early Pleistocene in this area.
