The Upper Cretaceous of Tantou Basin in western Henan has yielded many vertebrate fossils,which are featured by several non-avian dinosaurs.Meanwhile,studies on their eggs were yet inadequate though many eggshells hav...The Upper Cretaceous of Tantou Basin in western Henan has yielded many vertebrate fossils,which are featured by several non-avian dinosaurs.Meanwhile,studies on their eggs were yet inadequate though many eggshells have been reported.The newly discovered material 41HⅤ0199 was excavated from the Upper Cretaceous Qiupa Formation in 2021.The block preserves eight complete eggs arranged in two partial rings that form a partial clutch,and there are some scattered eggshells preserved closely with the block,showing a concave-up to concave-down ratio of 54.5:45.5,which indicates that the scattered eggshells come from the clutch and the clutch had been partially broken before it was buried.Based on morphological and microstructural characteristics,the eggs and eggshells can be assigned to Macroolithus yaotunensis(Elongatoolithidae),an oospecies known to be related to oviraptorids,which leads Yulong mini to be its probable producer.Besides,some eggshells show microstructural signs indicating egg retention,which marks the second example of egg retention in the oofamily Elongatoolithidae.展开更多
The special issue deals with the Cretaceous-Tertiary deserts in southwestern China and relevant sedimentological problems about deserts. The study area is located between 101°10＇- 107°00＇E and 28°00＇...The special issue deals with the Cretaceous-Tertiary deserts in southwestern China and relevant sedimentological problems about deserts. The study area is located between 101°10＇- 107°00＇E and 28°00＇-30°40′ N. The ancient desert study is so little in China that there has not been a systematic report about it up to now. Based on the study in many ways on Cretaceous-Tertiary deserts in southwestern China, plentiful data have been obtained. Though it is still a bit rough, the study is a good beginning of the ancient desert study in China. The main ideas and conclusions are summarized as follows.展开更多
A discontinuous line of ophiolitic bodies occurs along the Yarlung Zangbo Suture Zone (YTSZ), which stretches across southern Tibet and beyond. This zone marks the locus of collision between Eurasia and India in the E...A discontinuous line of ophiolitic bodies occurs along the Yarlung Zangbo Suture Zone (YTSZ), which stretches across southern Tibet and beyond. This zone marks the locus of collision between Eurasia and India in the Early Cenozoic. Should we assume that the entire Tethyan Ocean basin that lay between these two continental blocks was oceanic or might it have been more complex? Fragments of any terranes that developed within this once extensive ocean potentially lie within the YTSZ. Detailed investigations over the past three field seasons reveal the presence of several terranes distributed along this zone. Work is currently underway to analyze the nature of individual terranes and the timing of any inter\|relationships.展开更多
Marine uppermost Cretaceous to lowermost Tertiary sequence occurs in the Gamba and Tingri regions of southern Tibet. In previous work, the sequences in both regions were divided into the Zongshan, Jidula and Zhepure F...Marine uppermost Cretaceous to lowermost Tertiary sequence occurs in the Gamba and Tingri regions of southern Tibet. In previous work, the sequences in both regions were divided into the Zongshan, Jidula and Zhepure Formations (Wan, 1985; Hao and Wan, 1985; Xu, Wan, et al. 1990). The K/T boundary in Gamba was studied by Wan Xiaoqiao (1988). This paper deals with the boundary in the Tingri region. Willems (1993) discussed the Cretaceous to Tertiary sequence in the Tingri region. In his work, the Upper Cretaceous to Lower Tertiary passage beds involved the Zongshan, Zhepure Shanpo, Jidula and Zhepure Shan Formations. The lithologies in the Tingri and Gamba regions are generally comparable, and we describe the boundary sequence in the Tingri region as follows:1\ Zongshan Formation (Campanian—Middle Maastrichtian) Hao and Wan (1985) first described this formation in Tingri. It consists of limestones equivalent to the strata in Gamba. The nomination of the Zongshan formation has been used in both regions. The Formation in Gamba ranges from Campanian to Late Maastrichtian age. In Tingri, however, the upper beds were referred to the Zhepure Shanpo Formation because they are clastic sediments (Willems, 1993). Planktonic foraminifera are abundant, such as Globotruncana spp. and Omphalocyclus sp.展开更多
Abundant well-preserved Late Jurassic-Early Cretaceous radiolarian fossils were extracted from 31 bedded green chert samples collected from Zhilong section,Gyangse,southern Tibet.This
A section in the Zhepure Mountains near Old Tingri in SE-Tibet,ranging from the Upper Albian to Paleogene,was described in detail by Willems et al.(1996).These authors worked on the litho-and microfacies and set up th...A section in the Zhepure Mountains near Old Tingri in SE-Tibet,ranging from the Upper Albian to Paleogene,was described in detail by Willems et al.(1996).These authors worked on the litho-and microfacies and set up the biostratigraphical framework by planktonic foraminifera.Willems et al.(1996)established their section as a standard for southern Tibet and compared it to the Gamba area.During the 2004 Tibet-expedition of Chengdu University of Technology in China,in co-operation with Bremen and Kiel universities in Germany,the locality was revisited for the purpose of collecting invertebrate fossils.This field-work included only the Upper Cretaceous part of the Tingri section and its invertebrate faunal content.Until today almost no ammonite and inoceramid data existed for this section.This is true for most Cretaceous sections in Tibet,although the Upper Cretaceous succession was interpreted as shelf environment.which in other parts of the world contains rich faunas of these macrofossil groups.The newly discovered continuous record of rare ammonites and inoceramids is probably limited since the preservation in the wacke-and packstones is poor.In addition,sampling conditions were unfavorable and the environmental conditions disadvantageous for most groups of invertebrates,as possibly indicated by larger amounts of small bivalve debris(filaments)in the upper part of the Gamba Group.Although the collected fauna is sparse and poorly preserved,the following biostratigraphical data can be added to the hitherto described microfauna:Calycoceras?from the Upper Gamba Group is Late Cenomanian in age and is accompanied by indeterminable juvenile desmoceratids.Superjacent follows a record of the ammonite Forresteria sp.,indicating that this level in the upper part of the Gamba Group belongs to the Lower Coniacian.This supports the finding of Inoceramus(Cremnoceramus)waltersdorfensis?hannovrensis?from the same interval.Anagaudryceras?is an individual ammonite finding from the Zhepure Shanbei or Zhepure Shanpo Formation,corresponding to the Santonian-Maastrichtian part of the succession.展开更多
The Cyclostratigraphy study is increasingly important in the precise dating of the marine strata, especially in the Tethyan realm.Compared with the Western Tethys,the Cyclostratigraphy study on the Eastern Tethys is r...The Cyclostratigraphy study is increasingly important in the precise dating of the marine strata, especially in the Tethyan realm.Compared with the Western Tethys,the Cyclostratigraphy study on the Eastern Tethys is relatively insufficient.Cretaceous marine sediments are cropped out widely in Southern Tibet,among them the late Cretaceous in the Gongzha section of Tingri area is rather continuous and integral.展开更多
Clay mineral analyses of the Middle Jurassic through the Early Cretaceous sedimentary rocks from the Guangyuan-Jian’ge section,Sichuan Basin (southwestern China)were undertaken in this article, which is aiming to rec...Clay mineral analyses of the Middle Jurassic through the Early Cretaceous sedimentary rocks from the Guangyuan-Jian’ge section,Sichuan Basin (southwestern China)were undertaken in this article, which is aiming to reconstruct the palaeoclimate of the area.Relative contents of the four clay minerals, smectite(25.8%-1.0%-46.8%),kaolinite(31.0%- 12.5%-12.6%),illite(31.3%-68.0%-28.0%)and chlorite(11.8%-8.5%-12.6%),as the target clay minerals,illite crystalline index(0.26-0.31-0.27)and chemical index(0.62-0.66-0.79)are used as indicator of paleoclimate.It is indicated that changes of展开更多
The Songliao Basin,the biggest Cretaceous oil-gas producing lacustrine basin in northeast China, contains the giant Daqing Oilfield situated in the central part.Lacustrine setting dominated the basin during the Cretac...The Songliao Basin,the biggest Cretaceous oil-gas producing lacustrine basin in northeast China, contains the giant Daqing Oilfield situated in the central part.Lacustrine setting dominated the basin during the Cretaceous period.The SK-I drilling, located in the northern central part of the Songliao Basin,was completed in 2007 and is supposed to be a possible breakthrough in lake investigation.This paper aims to study the Cretaceous展开更多
Late Cretaceous lacustrine deposits in Songliao Basin provide a unique material to study the paleo-environment and paleoclimate of nomarine Cretaceous.Two large transgressions occurred during the Qingshankou and Nenji...Late Cretaceous lacustrine deposits in Songliao Basin provide a unique material to study the paleo-environment and paleoclimate of nomarine Cretaceous.Two large transgressions occurred during the Qingshankou and Nenjiang deposition times,the later of which was larger.Based on sedimentation,ostracode,TOC,HI,δ<sup>13</sup>C<sub>org</sub> and C/N from upper Yaojia Formation to Lower Nenjiang Formation in the eastern Songliao Basin。展开更多
Jehol Biota in western Liaoning and northern Hebei has been a hot topic of global concern,a large number of exquisite fossils were found in Yixian group Sihetun,such as Sinosauropteryx,Protarchaeopteryx, Caudipteryx a...Jehol Biota in western Liaoning and northern Hebei has been a hot topic of global concern,a large number of exquisite fossils were found in Yixian group Sihetun,such as Sinosauropteryx,Protarchaeopteryx, Caudipteryx and Confuciusornis.Scientists consider the discovering of Sinosauropteryx discovered so far as the earliest ancestor of birds.According to the dates of root layer,we can see warm and humid,lakes展开更多
The Qiangtang Basin located in northern Tibet is a Jurassic foreland basin, whereas the sedimentation for the arc\|basin system during the Late Triassic. Paleomagnetic sampling sites and sections include the Lower Jur...The Qiangtang Basin located in northern Tibet is a Jurassic foreland basin, whereas the sedimentation for the arc\|basin system during the Late Triassic. Paleomagnetic sampling sites and sections include the Lower Jurassic section in Juhuashan, Shuanhu district, the Middle and Upper Jurassic section in Nadigangri Mountain and the Lower Cretaceous section in Abushan, Shuanhu district. The Lower Jurassic Nadigangri Fm. is composed of tuffaceous volcanic rocks and turbidite (lower) and purple clastic rocks. The Middle Jurassic consists of Quemocuo Fm. purple clastics , Buqu Fm. carbonates and Xiali Fm. gypsum\|bearing varicolored clastics.The Upper Jurassic includes Suowa Fm. carbonates and Xueshan Fm. purple clastics. The Lower Cretaceous Abushan Fm. is lacustrine clastics.1723 oriented paleomagnetic samples of Jurassic and Cretaceous strata were collected in 1997.The sampling sections is located in Shuanhu district of northern Tibet. Although it is unlikely that the sections studied formed by constant and continuous deposition, field evidence indicates no major breaks in the Jurassic sedimentation, except early Bajocian stage. Based on sections of actual survey, all sampling was done using a portable gas\|powered core drill, and cores were oriented with magnetic compass and inclinometer. Samples were obtained at common stratigraphic spacing of 0 5～5m, partly 5cm at some important geological boundary\|surfaces and beds/members. 25mm diameter and 20～50mm length paleomagnetic core samples were drilled in cropping field. The measuring of most samples was completed at the China Academy of Geosciences Paleomagnetic Laboratory using a type DSM\|2 digital rotational magnetometer (its sensitivity of reaching 10 -5 A/m) made by SCHONSTEDT Company of U.S.A., and SCHONSTEDT TSD\|1 for thermal demagnetization. The apparatus used for AF demagnetization was a commercial (SCHONSTEDT GSD\|5)instrument, capable of reaching 100mT peak field. 10% of total measuring samples were completed at the Beijing Geological Institute Paleomagnetic Laboratory of China Academy of Sciences using a type 2G\|755R magnetometer made by Superconducting Technology for weak magnetized samples (sensitivity of reaching 10 -8 A/m). Most samples were stepwise thermally demagnetized, at 50℃ intervals from 100 to 700℃.展开更多
Most of the massive sulfide deposits (VMS) occurring from Precambrian to Cenozoic throughout the world has been subsequently metamorphosed at various grades. Thus, all the original textures have been either completely...Most of the massive sulfide deposits (VMS) occurring from Precambrian to Cenozoic throughout the world has been subsequently metamorphosed at various grades. Thus, all the original textures have been either completely destroyed or strongly modified. However, there are a very few examples, rather younger deposits such as late Cretaceous Turkish VMS deposits and Miocene Kuroko deposits of Japan in which representative and original ore textures are preserved. The Turkish massive sulfide deposits are mainly Cu-Zn-Pb-type and entirely hosted by Late Cretaceous felsic volcanic rocks within a paleoarc geotectonic setting.展开更多
The Cretaceous is a typical period for studying the greenhouse climate and the earth system interactions, and the world’s most extensive terrestrial strata are mainly in East Asia, especially in China. Continental se...The Cretaceous is a typical period for studying the greenhouse climate and the earth system interactions, and the world’s most extensive terrestrial strata are mainly in East Asia, especially in China. Continental sediments can effectively reflect the paleo-climate change, but the previous studies of the Late Cretaceous paleo-climate, based on the combined characteristics of continental climate-sensitive sediments, were barely found in China. To obtain the Late Cretaceous paleo-climate characteristics of China, the distribution characteristics of different continental climate-sensitive sediment types in the early, middle and Late Cretaceous in China were studied in detail. According to the distribution and combination characteristics and types of continental climate-sensitive sediments, seven climate types can be divided: 1) warm-humid and warm-dry climate;2) hot and dry climate;3) hot-dry and arid climate;4) hot-dry and semiarid climate;5) hot-dry and hot-wet climate;6) hot-dry and warm-humid climate;7) hot-dry and warm-dry climate. The results show that in the early Late Cretaceous, the hot and dry climate was the most widespread, followed by warm-humid and warm-dry climate, but the climate was drier than the paleo-climate of the previous study of Early Cretaceous. Hot and dry climate zone became wider in the Coniacian and Maastrichtian;furthermore, it covered Xinjiang to the east of China from east to west after the Santonian Period. The hot-dry and semiarid climate zone was nearly latitudinally distributed from the northwest to the southeast and it shows a further increase in aridification. Global geological events, paleogeographic features and regional tectonic evolution had significant impacts on the paleoclimate of China in the Late Cretaceous, such as global eruptive events of volcanoes led to the temperature increase in China in the early Late Cretaceous;coastal mountain ranges in southeastern China led to the drying of the Late Cretaceous climate in southern China;Xuefeng Mountains, Wuling Mountains, Nanling Mountains and Tai-hang Mountains were the dividing line between the hot and dry climate zone and hot-dry and arid climate zone in the early Late Cretaceous, and Altun Mountains were the dividing line between the southeastern section of the hot and dry climate zone in western China in the middle Late Cretaceous.展开更多
This report is about the first record of non-avian dinosaur eggs in the Hefei Basin,Anhui Province,China.Based on the combination of elongated egg body,linear ridges on the outer surface and two structure layer,the eg...This report is about the first record of non-avian dinosaur eggs in the Hefei Basin,Anhui Province,China.Based on the combination of elongated egg body,linear ridges on the outer surface and two structure layer,the eggs can be referred to Elongatoolithidae.The gradual boundary between the cone and the column layers as well as the relative thin eggshell(less than 1 mm)indicates its affinity within Elongatoolithus.The eggs are identified as Elongatoolithus oosp.,as they were severely compressed and experienced erosion on both inner and outer surfaces.The discovery of egg fossil in the Hefei Basin offers evidence for stratum comparison in this region and supplements the diversity of egg fossils in Anhui.Meanwhile,this discovery also enriches the paleogeographic distribution of elongatoolithids.展开更多
This is an extended abstract of Hu et al.,2012. The timing of the initial collision between India and Asia remains a matter of considerable debate,with views ranging from～70 Ma to～35 Ma.Here the initial India-Asia c...This is an extended abstract of Hu et al.,2012. The timing of the initial collision between India and Asia remains a matter of considerable debate,with views ranging from～70 Ma to～35 Ma.Here the initial India-Asia contact is defined as the time at which the展开更多
文摘The Upper Cretaceous of Tantou Basin in western Henan has yielded many vertebrate fossils,which are featured by several non-avian dinosaurs.Meanwhile,studies on their eggs were yet inadequate though many eggshells have been reported.The newly discovered material 41HⅤ0199 was excavated from the Upper Cretaceous Qiupa Formation in 2021.The block preserves eight complete eggs arranged in two partial rings that form a partial clutch,and there are some scattered eggshells preserved closely with the block,showing a concave-up to concave-down ratio of 54.5:45.5,which indicates that the scattered eggshells come from the clutch and the clutch had been partially broken before it was buried.Based on morphological and microstructural characteristics,the eggs and eggshells can be assigned to Macroolithus yaotunensis(Elongatoolithidae),an oospecies known to be related to oviraptorids,which leads Yulong mini to be its probable producer.Besides,some eggshells show microstructural signs indicating egg retention,which marks the second example of egg retention in the oofamily Elongatoolithidae.
文摘The special issue deals with the Cretaceous-Tertiary deserts in southwestern China and relevant sedimentological problems about deserts. The study area is located between 101°10＇- 107°00＇E and 28°00＇-30°40′ N. The ancient desert study is so little in China that there has not been a systematic report about it up to now. Based on the study in many ways on Cretaceous-Tertiary deserts in southwestern China, plentiful data have been obtained. Though it is still a bit rough, the study is a good beginning of the ancient desert study in China. The main ideas and conclusions are summarized as follows.
文摘A discontinuous line of ophiolitic bodies occurs along the Yarlung Zangbo Suture Zone (YTSZ), which stretches across southern Tibet and beyond. This zone marks the locus of collision between Eurasia and India in the Early Cenozoic. Should we assume that the entire Tethyan Ocean basin that lay between these two continental blocks was oceanic or might it have been more complex? Fragments of any terranes that developed within this once extensive ocean potentially lie within the YTSZ. Detailed investigations over the past three field seasons reveal the presence of several terranes distributed along this zone. Work is currently underway to analyze the nature of individual terranes and the timing of any inter\|relationships.
文摘Marine uppermost Cretaceous to lowermost Tertiary sequence occurs in the Gamba and Tingri regions of southern Tibet. In previous work, the sequences in both regions were divided into the Zongshan, Jidula and Zhepure Formations (Wan, 1985; Hao and Wan, 1985; Xu, Wan, et al. 1990). The K/T boundary in Gamba was studied by Wan Xiaoqiao (1988). This paper deals with the boundary in the Tingri region. Willems (1993) discussed the Cretaceous to Tertiary sequence in the Tingri region. In his work, the Upper Cretaceous to Lower Tertiary passage beds involved the Zongshan, Zhepure Shanpo, Jidula and Zhepure Shan Formations. The lithologies in the Tingri and Gamba regions are generally comparable, and we describe the boundary sequence in the Tingri region as follows:1\ Zongshan Formation (Campanian—Middle Maastrichtian) Hao and Wan (1985) first described this formation in Tingri. It consists of limestones equivalent to the strata in Gamba. The nomination of the Zongshan formation has been used in both regions. The Formation in Gamba ranges from Campanian to Late Maastrichtian age. In Tingri, however, the upper beds were referred to the Zhepure Shanpo Formation because they are clastic sediments (Willems, 1993). Planktonic foraminifera are abundant, such as Globotruncana spp. and Omphalocyclus sp.
文摘Abundant well-preserved Late Jurassic-Early Cretaceous radiolarian fossils were extracted from 31 bedded green chert samples collected from Zhilong section,Gyangse,southern Tibet.This
文摘A section in the Zhepure Mountains near Old Tingri in SE-Tibet,ranging from the Upper Albian to Paleogene,was described in detail by Willems et al.(1996).These authors worked on the litho-and microfacies and set up the biostratigraphical framework by planktonic foraminifera.Willems et al.(1996)established their section as a standard for southern Tibet and compared it to the Gamba area.During the 2004 Tibet-expedition of Chengdu University of Technology in China,in co-operation with Bremen and Kiel universities in Germany,the locality was revisited for the purpose of collecting invertebrate fossils.This field-work included only the Upper Cretaceous part of the Tingri section and its invertebrate faunal content.Until today almost no ammonite and inoceramid data existed for this section.This is true for most Cretaceous sections in Tibet,although the Upper Cretaceous succession was interpreted as shelf environment.which in other parts of the world contains rich faunas of these macrofossil groups.The newly discovered continuous record of rare ammonites and inoceramids is probably limited since the preservation in the wacke-and packstones is poor.In addition,sampling conditions were unfavorable and the environmental conditions disadvantageous for most groups of invertebrates,as possibly indicated by larger amounts of small bivalve debris(filaments)in the upper part of the Gamba Group.Although the collected fauna is sparse and poorly preserved,the following biostratigraphical data can be added to the hitherto described microfauna:Calycoceras?from the Upper Gamba Group is Late Cenomanian in age and is accompanied by indeterminable juvenile desmoceratids.Superjacent follows a record of the ammonite Forresteria sp.,indicating that this level in the upper part of the Gamba Group belongs to the Lower Coniacian.This supports the finding of Inoceramus(Cremnoceramus)waltersdorfensis?hannovrensis?from the same interval.Anagaudryceras?is an individual ammonite finding from the Zhepure Shanbei or Zhepure Shanpo Formation,corresponding to the Santonian-Maastrichtian part of the succession.
文摘The Cyclostratigraphy study is increasingly important in the precise dating of the marine strata, especially in the Tethyan realm.Compared with the Western Tethys,the Cyclostratigraphy study on the Eastern Tethys is relatively insufficient.Cretaceous marine sediments are cropped out widely in Southern Tibet,among them the late Cretaceous in the Gongzha section of Tingri area is rather continuous and integral.
文摘Clay mineral analyses of the Middle Jurassic through the Early Cretaceous sedimentary rocks from the Guangyuan-Jian’ge section,Sichuan Basin (southwestern China)were undertaken in this article, which is aiming to reconstruct the palaeoclimate of the area.Relative contents of the four clay minerals, smectite(25.8%-1.0%-46.8%),kaolinite(31.0%- 12.5%-12.6%),illite(31.3%-68.0%-28.0%)and chlorite(11.8%-8.5%-12.6%),as the target clay minerals,illite crystalline index(0.26-0.31-0.27)and chemical index(0.62-0.66-0.79)are used as indicator of paleoclimate.It is indicated that changes of
文摘The Songliao Basin,the biggest Cretaceous oil-gas producing lacustrine basin in northeast China, contains the giant Daqing Oilfield situated in the central part.Lacustrine setting dominated the basin during the Cretaceous period.The SK-I drilling, located in the northern central part of the Songliao Basin,was completed in 2007 and is supposed to be a possible breakthrough in lake investigation.This paper aims to study the Cretaceous
文摘Late Cretaceous lacustrine deposits in Songliao Basin provide a unique material to study the paleo-environment and paleoclimate of nomarine Cretaceous.Two large transgressions occurred during the Qingshankou and Nenjiang deposition times,the later of which was larger.Based on sedimentation,ostracode,TOC,HI,δ<sup>13</sup>C<sub>org</sub> and C/N from upper Yaojia Formation to Lower Nenjiang Formation in the eastern Songliao Basin。
文摘Jehol Biota in western Liaoning and northern Hebei has been a hot topic of global concern,a large number of exquisite fossils were found in Yixian group Sihetun,such as Sinosauropteryx,Protarchaeopteryx, Caudipteryx and Confuciusornis.Scientists consider the discovering of Sinosauropteryx discovered so far as the earliest ancestor of birds.According to the dates of root layer,we can see warm and humid,lakes
文摘The Qiangtang Basin located in northern Tibet is a Jurassic foreland basin, whereas the sedimentation for the arc\|basin system during the Late Triassic. Paleomagnetic sampling sites and sections include the Lower Jurassic section in Juhuashan, Shuanhu district, the Middle and Upper Jurassic section in Nadigangri Mountain and the Lower Cretaceous section in Abushan, Shuanhu district. The Lower Jurassic Nadigangri Fm. is composed of tuffaceous volcanic rocks and turbidite (lower) and purple clastic rocks. The Middle Jurassic consists of Quemocuo Fm. purple clastics , Buqu Fm. carbonates and Xiali Fm. gypsum\|bearing varicolored clastics.The Upper Jurassic includes Suowa Fm. carbonates and Xueshan Fm. purple clastics. The Lower Cretaceous Abushan Fm. is lacustrine clastics.1723 oriented paleomagnetic samples of Jurassic and Cretaceous strata were collected in 1997.The sampling sections is located in Shuanhu district of northern Tibet. Although it is unlikely that the sections studied formed by constant and continuous deposition, field evidence indicates no major breaks in the Jurassic sedimentation, except early Bajocian stage. Based on sections of actual survey, all sampling was done using a portable gas\|powered core drill, and cores were oriented with magnetic compass and inclinometer. Samples were obtained at common stratigraphic spacing of 0 5～5m, partly 5cm at some important geological boundary\|surfaces and beds/members. 25mm diameter and 20～50mm length paleomagnetic core samples were drilled in cropping field. The measuring of most samples was completed at the China Academy of Geosciences Paleomagnetic Laboratory using a type DSM\|2 digital rotational magnetometer (its sensitivity of reaching 10 -5 A/m) made by SCHONSTEDT Company of U.S.A., and SCHONSTEDT TSD\|1 for thermal demagnetization. The apparatus used for AF demagnetization was a commercial (SCHONSTEDT GSD\|5)instrument, capable of reaching 100mT peak field. 10% of total measuring samples were completed at the Beijing Geological Institute Paleomagnetic Laboratory of China Academy of Sciences using a type 2G\|755R magnetometer made by Superconducting Technology for weak magnetized samples (sensitivity of reaching 10 -8 A/m). Most samples were stepwise thermally demagnetized, at 50℃ intervals from 100 to 700℃.
文摘Most of the massive sulfide deposits (VMS) occurring from Precambrian to Cenozoic throughout the world has been subsequently metamorphosed at various grades. Thus, all the original textures have been either completely destroyed or strongly modified. However, there are a very few examples, rather younger deposits such as late Cretaceous Turkish VMS deposits and Miocene Kuroko deposits of Japan in which representative and original ore textures are preserved. The Turkish massive sulfide deposits are mainly Cu-Zn-Pb-type and entirely hosted by Late Cretaceous felsic volcanic rocks within a paleoarc geotectonic setting.
基金A project funded by National Natural Science Foundation of China(41572093)Central Young College Teachers Fund Project (3142020002)Supported by the Fundamental Research Funds for the Central Universities(3142021004)。
文摘The Cretaceous is a typical period for studying the greenhouse climate and the earth system interactions, and the world’s most extensive terrestrial strata are mainly in East Asia, especially in China. Continental sediments can effectively reflect the paleo-climate change, but the previous studies of the Late Cretaceous paleo-climate, based on the combined characteristics of continental climate-sensitive sediments, were barely found in China. To obtain the Late Cretaceous paleo-climate characteristics of China, the distribution characteristics of different continental climate-sensitive sediment types in the early, middle and Late Cretaceous in China were studied in detail. According to the distribution and combination characteristics and types of continental climate-sensitive sediments, seven climate types can be divided: 1) warm-humid and warm-dry climate;2) hot and dry climate;3) hot-dry and arid climate;4) hot-dry and semiarid climate;5) hot-dry and hot-wet climate;6) hot-dry and warm-humid climate;7) hot-dry and warm-dry climate. The results show that in the early Late Cretaceous, the hot and dry climate was the most widespread, followed by warm-humid and warm-dry climate, but the climate was drier than the paleo-climate of the previous study of Early Cretaceous. Hot and dry climate zone became wider in the Coniacian and Maastrichtian;furthermore, it covered Xinjiang to the east of China from east to west after the Santonian Period. The hot-dry and semiarid climate zone was nearly latitudinally distributed from the northwest to the southeast and it shows a further increase in aridification. Global geological events, paleogeographic features and regional tectonic evolution had significant impacts on the paleoclimate of China in the Late Cretaceous, such as global eruptive events of volcanoes led to the temperature increase in China in the early Late Cretaceous;coastal mountain ranges in southeastern China led to the drying of the Late Cretaceous climate in southern China;Xuefeng Mountains, Wuling Mountains, Nanling Mountains and Tai-hang Mountains were the dividing line between the hot and dry climate zone and hot-dry and arid climate zone in the early Late Cretaceous, and Altun Mountains were the dividing line between the southeastern section of the hot and dry climate zone in western China in the middle Late Cretaceous.
文摘This report is about the first record of non-avian dinosaur eggs in the Hefei Basin,Anhui Province,China.Based on the combination of elongated egg body,linear ridges on the outer surface and two structure layer,the eggs can be referred to Elongatoolithidae.The gradual boundary between the cone and the column layers as well as the relative thin eggshell(less than 1 mm)indicates its affinity within Elongatoolithus.The eggs are identified as Elongatoolithus oosp.,as they were severely compressed and experienced erosion on both inner and outer surfaces.The discovery of egg fossil in the Hefei Basin offers evidence for stratum comparison in this region and supplements the diversity of egg fossils in Anhui.Meanwhile,this discovery also enriches the paleogeographic distribution of elongatoolithids.
文摘This is an extended abstract of Hu et al.,2012. The timing of the initial collision between India and Asia remains a matter of considerable debate,with views ranging from～70 Ma to～35 Ma.Here the initial India-Asia contact is defined as the time at which the
