Deccan volcanic sequences （DYS） in the central Deccan volcanic province （CDYP） are designated as Sahyadri Group having -500 m thick lava pile associated with multiple sedimentary beds at different strati-graphic l...Deccan volcanic sequences （DYS） in the central Deccan volcanic province （CDYP） are designated as Sahyadri Group having -500 m thick lava pile associated with multiple sedimentary beds at different strati-graphic levels. In the eastern part of CDYP between the latitude 19°55-20°25 ′N and the longitudes 78°15-78° 30′E, palynological investigation of the intertrappean sedimentary beds at five stratigraphic levels was carried out. The study was basically aimed for tracking the floral and environmental changes across the Deccan transi-tion. The resulting finds indicate that the intertrappean sediments at the lowest stratigraphic level between the earliest lava flows are characterized by presence of marker Maastrichtian palynomorphs - Gabonisporis vigour- ouxii, Aquilapollenites bengalensis, Azolla cretacea and Farabeipollis associated with triporate and tricolpate pol-len grains, phytoliths of Oryzeae of Poaceae family and peridinoid dinoflagellate cysts. The increasing volcanism deteriorated the existing flora as evident by absence of pollen-spores and presence of only structured biodegraded organic matter, fungal spores, acritarchs and algal （Botryococcus） remains in the sediments of higher-up in the sequence. For chronostratigraphic constraints on the lava flows magnetic polarity of the flows bracketing the in-tertrappean beds was investigated. The results indicated presence of N-R-N-R magnetic polarity in the basal la-va pile that are interpreted as representing the magnetochron C30N to C28R （ Maastrichtian-Paleogene）. The floral change begins with the onset of volcanism in the chron C30N and floral deterioration is observed in C29N with increasing volcanism and it is only in the chron C28 R （ Danian） that some evidence of recovery of flora is recorded. The current study shows that in eastern part of CDYP the post Cretaceous-Paleogene boundary erup-tions represent the main phase of eruptions that triggered deterioration of the flora.展开更多
Considered the question about stratigraphic position of coal-bearing continental deposits of the Amur area,the main attention is paid to the definition of pollen of angiosperms.Khlonova(1960),Zaklinskaya(1963),Bratsev...Considered the question about stratigraphic position of coal-bearing continental deposits of the Amur area,the main attention is paid to the definition of pollen of angiosperms.Khlonova(1960),Zaklinskaya(1963),Bratseva(1969) and other scientists reported a lot about the significance of the pollen.Among the new taxa the special interest represents the first description of Engelhardtia pollen of late Maestrichtian and Paleocene deposits.A new kind of pollen Vacuopollis triplicatus sp.nov.is described.展开更多
Cretaceous climate was warmer than today.The Songliao Basin contains one of the most important Late Cretaceous non-marine deposits in China for the research of the paleoenvironment and paleoclimate.This research is ba...Cretaceous climate was warmer than today.The Songliao Basin contains one of the most important Late Cretaceous non-marine deposits in China for the research of the paleoenvironment and paleoclimate.This research is based on core samples from the SK1(S)borehole.The strata sampled are the upper part of the Quantou Formation to member 2 of the Nenjiang Formation,where spores,pollen,dinoflagellates,and other microfossils are abundantly preserved.Based on analysis of the spores and pollen fossils from the core samples,the following six fossil assemblage zones have been recognized in ascending order:The Cicatricosisporites-Cyathidites-Pinuspollenites,Schizaeoisporites-Cyathidites-Classopollis,Cyathidites-Schizaeoisporites,Schizaeoisporites-Cyathidites-Proteacidites,Proteacidites-Cyathidites-Dictyotriletes,and the Lythraites-Callistipollenites-Schizaeoisporites zones.The six fossil zones range from the late Cenomanian to early Campanian.The Late Cretaceous dinoflagellate cysts in the Songliao Basin are of high abundance and low diversity.Specific phytoplankton types reflect salinity changes of the Songliao Lake.Paleoecology of the dinoflagellates suggests that sediments of members 2 and 3 of the Yaojia Formation(K2y2+3)were deposited in a freshwater environment,whereas members 2 and 3 of the Qingshankou Formation(K2q2+3)and members 1 and 2 of the Nenjiang Formation(K2n1+2)were deposited in freshwater to brackish water environments.Combined with the paleoecology of dinoflagellates and the palynomorph biozones,valuable information of the paleoclimate was provided.The quantitative analyses of spores and pollen fossils,such as vegetation type,climate type,and humidity type,diversity and dominance,indicate a relatively sub-humid,mid-subtropical paleoclimate,with slight climatic fluctuation and/or temporal change.展开更多
基金SERB-DST ( no. SR / S4 / ES619 /2012 ) for financial assistance
文摘Deccan volcanic sequences （DYS） in the central Deccan volcanic province （CDYP） are designated as Sahyadri Group having -500 m thick lava pile associated with multiple sedimentary beds at different strati-graphic levels. In the eastern part of CDYP between the latitude 19°55-20°25 ′N and the longitudes 78°15-78° 30′E, palynological investigation of the intertrappean sedimentary beds at five stratigraphic levels was carried out. The study was basically aimed for tracking the floral and environmental changes across the Deccan transi-tion. The resulting finds indicate that the intertrappean sediments at the lowest stratigraphic level between the earliest lava flows are characterized by presence of marker Maastrichtian palynomorphs - Gabonisporis vigour- ouxii, Aquilapollenites bengalensis, Azolla cretacea and Farabeipollis associated with triporate and tricolpate pol-len grains, phytoliths of Oryzeae of Poaceae family and peridinoid dinoflagellate cysts. The increasing volcanism deteriorated the existing flora as evident by absence of pollen-spores and presence of only structured biodegraded organic matter, fungal spores, acritarchs and algal （Botryococcus） remains in the sediments of higher-up in the sequence. For chronostratigraphic constraints on the lava flows magnetic polarity of the flows bracketing the in-tertrappean beds was investigated. The results indicated presence of N-R-N-R magnetic polarity in the basal la-va pile that are interpreted as representing the magnetochron C30N to C28R （ Maastrichtian-Paleogene）. The floral change begins with the onset of volcanism in the chron C30N and floral deterioration is observed in C29N with increasing volcanism and it is only in the chron C28 R （ Danian） that some evidence of recovery of flora is recorded. The current study shows that in eastern part of CDYP the post Cretaceous-Paleogene boundary erup-tions represent the main phase of eruptions that triggered deterioration of the flora.
基金the Project 30220130698 (NSFC)Project 111 of China for supporting to publish this paper
文摘Considered the question about stratigraphic position of coal-bearing continental deposits of the Amur area,the main attention is paid to the definition of pollen of angiosperms.Khlonova(1960),Zaklinskaya(1963),Bratseva(1969) and other scientists reported a lot about the significance of the pollen.Among the new taxa the special interest represents the first description of Engelhardtia pollen of late Maestrichtian and Paleocene deposits.A new kind of pollen Vacuopollis triplicatus sp.nov.is described.
基金supported by National Basic Research Program of China(Grant No.2012CB822002)National Natural Science Foundation of China(Grant No.41172037),China Geological Survey(Grant No.1212011120145)+1 种基金State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,CAS)(Grant No.123111)Fundamental Research Funds for the Central Universities(Grant No.2012011)
文摘Cretaceous climate was warmer than today.The Songliao Basin contains one of the most important Late Cretaceous non-marine deposits in China for the research of the paleoenvironment and paleoclimate.This research is based on core samples from the SK1(S)borehole.The strata sampled are the upper part of the Quantou Formation to member 2 of the Nenjiang Formation,where spores,pollen,dinoflagellates,and other microfossils are abundantly preserved.Based on analysis of the spores and pollen fossils from the core samples,the following six fossil assemblage zones have been recognized in ascending order:The Cicatricosisporites-Cyathidites-Pinuspollenites,Schizaeoisporites-Cyathidites-Classopollis,Cyathidites-Schizaeoisporites,Schizaeoisporites-Cyathidites-Proteacidites,Proteacidites-Cyathidites-Dictyotriletes,and the Lythraites-Callistipollenites-Schizaeoisporites zones.The six fossil zones range from the late Cenomanian to early Campanian.The Late Cretaceous dinoflagellate cysts in the Songliao Basin are of high abundance and low diversity.Specific phytoplankton types reflect salinity changes of the Songliao Lake.Paleoecology of the dinoflagellates suggests that sediments of members 2 and 3 of the Yaojia Formation(K2y2+3)were deposited in a freshwater environment,whereas members 2 and 3 of the Qingshankou Formation(K2q2+3)and members 1 and 2 of the Nenjiang Formation(K2n1+2)were deposited in freshwater to brackish water environments.Combined with the paleoecology of dinoflagellates and the palynomorph biozones,valuable information of the paleoclimate was provided.The quantitative analyses of spores and pollen fossils,such as vegetation type,climate type,and humidity type,diversity and dominance,indicate a relatively sub-humid,mid-subtropical paleoclimate,with slight climatic fluctuation and/or temporal change.
