2003 Vol. 22 No. 2
2003, 22(2): 71-86.
2003, 22(2): 87-94.
Abstract：
The genus of large-sized acanthomorphic acritarchs ,Tianzhushania,was named from Tianzhu Mountain in Changyang County,Hubei Province,where it was first described,and its typical species was first found from chert nodules(in thin sections )from the Sinian Doushantuo Formation.In this paper,the authors summarize the reports and researches about the genus published at home and abroad in the past20-odd years.On that basis,combined with the latest study of the relationships between Tianzhushania tuberifera Yin,Gao and Xing2000,preserved in siliceous rocks,and Megasphaera ornata Xiao and Knoll2000,which are pellet body fossils preserved by prophorization in the Sinian Doushantuo Formation,the authors discuss such problems as the morphological features,geographical distribution,stratigraphic signifi-cance and possible affinity of the large-sized acanthomorphic genus Tianzhushania.
The genus of large-sized acanthomorphic acritarchs ,Tianzhushania,was named from Tianzhu Mountain in Changyang County,Hubei Province,where it was first described,and its typical species was first found from chert nodules(in thin sections )from the Sinian Doushantuo Formation.In this paper,the authors summarize the reports and researches about the genus published at home and abroad in the past20-odd years.On that basis,combined with the latest study of the relationships between Tianzhushania tuberifera Yin,Gao and Xing2000,preserved in siliceous rocks,and Megasphaera ornata Xiao and Knoll2000,which are pellet body fossils preserved by prophorization in the Sinian Doushantuo Formation,the authors discuss such problems as the morphological features,geographical distribution,stratigraphic signifi-cance and possible affinity of the large-sized acanthomorphic genus Tianzhushania.
2003, 22(2): 95-104.
Abstract：
In an intensive study of fossil conchostracans from the Lower Cretaceous Dadianzi Formation in the Luanping basin,northern Hebei,the authors found the genus Clithrograpta W.Wang,1987in the upper part of this formation.It is characterized by occurrence in many beds,large numbers of individuals and a high diversity of species.This discovery provides key and strong paleontological evidence for the stratigraphic division and correlation in the Lower Cretaceous Dadianzi Formation in the Luanping basin,northern Hebei and the correct establishment of the continental Jurassic-Cretaceous stratigraphic framework in northern Hebei-western Liaoning.According to this discovery and the conchostracan assemblage se-quence in the Dabeigou Formation and Xiguayuan Formation,the upper part(3rd and4th Members)of the Dadianzi Formation in the area may be correlated with the lower part(original Daxinfangzi Formation)of the"Yixian Formation"in the Jianchang basin,western Liaoning,suggesting that the lower part(1st and2nd Members)of the Dadianzi Formation of the area is absent in western Liaoning;the Xiguayuan Formation is largely equivalent to the Yixian Formation of western Liaoning.
In an intensive study of fossil conchostracans from the Lower Cretaceous Dadianzi Formation in the Luanping basin,northern Hebei,the authors found the genus Clithrograpta W.Wang,1987in the upper part of this formation.It is characterized by occurrence in many beds,large numbers of individuals and a high diversity of species.This discovery provides key and strong paleontological evidence for the stratigraphic division and correlation in the Lower Cretaceous Dadianzi Formation in the Luanping basin,northern Hebei and the correct establishment of the continental Jurassic-Cretaceous stratigraphic framework in northern Hebei-western Liaoning.According to this discovery and the conchostracan assemblage se-quence in the Dabeigou Formation and Xiguayuan Formation,the upper part(3rd and4th Members)of the Dadianzi Formation in the area may be correlated with the lower part(original Daxinfangzi Formation)of the"Yixian Formation"in the Jianchang basin,western Liaoning,suggesting that the lower part(1st and2nd Members)of the Dadianzi Formation of the area is absent in western Liaoning;the Xiguayuan Formation is largely equivalent to the Yixian Formation of western Liaoning.
2003, 22(2): 105-112.
Abstract：
According to the regional tectonic layer division and proceeding from a dynamic analysis of faults in the youngest strata,analysis was performed layer by layer along the Tanlu fault zone.Through sta-tistical analysis and calculation of striations on fault planes by means of the computer program,the pale-ostress state at every point is obtained,and then the state of the regional paleostress field is obtained.After that,the characters of paleostress fields in which fault movements occur in different periods of time can be determined.Finally a complete and successive evolutionary sequence of the paleostress field can be deter-mined.On that basis,combined with an analysis of the features of regional tectonic deformation the se-quence of tectonic events occurring in the fault zone and its significance can be elucidated.
According to the regional tectonic layer division and proceeding from a dynamic analysis of faults in the youngest strata,analysis was performed layer by layer along the Tanlu fault zone.Through sta-tistical analysis and calculation of striations on fault planes by means of the computer program,the pale-ostress state at every point is obtained,and then the state of the regional paleostress field is obtained.After that,the characters of paleostress fields in which fault movements occur in different periods of time can be determined.Finally a complete and successive evolutionary sequence of the paleostress field can be deter-mined.On that basis,combined with an analysis of the features of regional tectonic deformation the se-quence of tectonic events occurring in the fault zone and its significance can be elucidated.
2003, 22(2): 113-117.
Abstract：
A Carboniferous strontium isotope evolutionary curve was constructed based on22data of strontium isotope analyses of unaltered marine rock samples collected from a Carboniferous section at Ma-jiaoba,Jiangyou,Sichuan.The variation trend of this curve is consistent on the whole with that of the contemporaneous strontium isotope curves constructed using samples from Huishui ,Guizhou,China,and from North America,showing the importance of strontium isotope curves for the chronostratigraphic cor-relation of marine strata.According to the correlation of these curves,this paper discusses the chronostrati-graphic division of the Carboniferous section in Majiaoba and the sea level changes.
A Carboniferous strontium isotope evolutionary curve was constructed based on22data of strontium isotope analyses of unaltered marine rock samples collected from a Carboniferous section at Ma-jiaoba,Jiangyou,Sichuan.The variation trend of this curve is consistent on the whole with that of the contemporaneous strontium isotope curves constructed using samples from Huishui ,Guizhou,China,and from North America,showing the importance of strontium isotope curves for the chronostratigraphic cor-relation of marine strata.According to the correlation of these curves,this paper discusses the chronostrati-graphic division of the Carboniferous section in Majiaoba and the sea level changes.
2003, 22(2): 118-123.
Abstract：
The Anzishan super-unit consists of four units,and magmatic emplacement deformational struc-tures are developed to different degrees in these units.The main structure is foliation,and dioritic inclu-sions and K-feldspar phenocrysts generally display preferred orientation.The three have a consistent attitude and are distributed parallelly to the contact zone.From the early-formed units to late-formed unit,with weakening deformation intensity of magmatic emplacement foliation structure,the number of dioritic inclu-sions is reduced,the degree of flattening deformation decreases and the oriented K-feldspar phenocrysts are distributed at random.According to the above-mentioned features,the magmatic emplacement deforma-tional structures of this super-unit is classified into strong emplacement deformation,moderate emplacement deformation,weak emplacement deformation and essentially no emplacement deformation zones.
The Anzishan super-unit consists of four units,and magmatic emplacement deformational struc-tures are developed to different degrees in these units.The main structure is foliation,and dioritic inclu-sions and K-feldspar phenocrysts generally display preferred orientation.The three have a consistent attitude and are distributed parallelly to the contact zone.From the early-formed units to late-formed unit,with weakening deformation intensity of magmatic emplacement foliation structure,the number of dioritic inclu-sions is reduced,the degree of flattening deformation decreases and the oriented K-feldspar phenocrysts are distributed at random.According to the above-mentioned features,the magmatic emplacement deforma-tional structures of this super-unit is classified into strong emplacement deformation,moderate emplacement deformation,weak emplacement deformation and essentially no emplacement deformation zones.
2003, 22(2): 124-129.
2003, 22(2): 130-134.
Abstract：
The recent progress of trace element analytical methods used in geological survey projects was briefly described.The methods included were:determination of platinum group elements by Nis fire assy-ICPMS;determination of 47Trace elements by sealed pressurized acid digestion-ICP-MS;the new meth-ods for determination of halogens and other nonmetals elements.
The recent progress of trace element analytical methods used in geological survey projects was briefly described.The methods included were:determination of platinum group elements by Nis fire assy-ICPMS;determination of 47Trace elements by sealed pressurized acid digestion-ICP-MS;the new meth-ods for determination of halogens and other nonmetals elements.
2003, 22(2): 135-139.
Abstract：
This paper briefly deals with the principle and features of detecting directly underground water with the surface nuclear magnetic resonance(NMR )method and illustrates by case histories that this method has yielded good results in groundwater detection in11provinces(regions )of China.It is suggested that researches on the improvement of the antielectric and antimagnetic interference abilities of the NMR hy-droscope and increase of the detection depth should be carried out so as to improve the suitability of the new method.
This paper briefly deals with the principle and features of detecting directly underground water with the surface nuclear magnetic resonance(NMR )method and illustrates by case histories that this method has yielded good results in groundwater detection in11provinces(regions )of China.It is suggested that researches on the improvement of the antielectric and antimagnetic interference abilities of the NMR hy-droscope and increase of the detection depth should be carried out so as to improve the suitability of the new method.
2003, 22(2): 140-141.
2003, 22(2): 142-143.
