The relationships and boundary between the North China and Tarim plates have been unclear for a long time ; however, the two plates occupy a prominent position in the formation and evolution of the continental lithosp...The relationships and boundary between the North China and Tarim plates have been unclear for a long time ; however, the two plates occupy a prominent position in the formation and evolution of the continental lithosphere of China. It is proposed that the Engger Us ophiolitic melange zone discovered recently north of Alaxa is a typical suture between the two plates. The ophiolitic melange zone is composed mainly of a mixture of fragments of ancient oceanic crust and sedimentary rocks of active and passive continental margins. The melange may be divided into tectonic inclusions and matrix. The suture extends northeastwards into the Republic of Mongolia and probably westwards to meet the Altun fault. With the Engger Us ophiolitic melange zone as the boundary the Alaxa area may be divided into two parts: the northern part (AN ) belongs to the Tarim plate, while the southern part (AS) the North China plate. Geological evidence shows that the two plates were amalgamated in the Late Permian or a bit later.展开更多
samples of limestones, mudrocks shales and tillites from the Sinian in Kuluketage have been analyzed. Four formations in the Sinian belong to glacial deposits in which the differences in d 13C are distinct (14.7‰—+...samples of limestones, mudrocks shales and tillites from the Sinian in Kuluketage have been analyzed. Four formations in the Sinian belong to glacial deposits in which the differences in d 13C are distinct (14.7‰—+4.2‰). Distinctly negative d 13C excursions for three times support the view of three glacial deposits in this area suggested by previous authors, except for the durations of them. d 13C values are generally positive in the Beiyixi Formation of lower part of the Lower Sinian, representing probably the rock records of a continental rift related to break-up of the Rodinian supercontinent. There are three times of distinct excursions of d 13C curve in all strata. The first one is from positive values at the bottom to about -5‰ at the top of the Beiyixi Formation. The second one, from 0‰—3‰ in the Arletonggou Formation of upper part of the Lower Sinian to 3.4‰— 14.4‰ in the Teruiaiken Formation. The third one, from positive values in the Zhamoketi Formation of lower part of the Upper Sinian to negative values in glacial varves at the top of the Hankeerqiaoke Formation.展开更多
Callipterid is an important and highly heterogeneous group of fossil plants in the Permian continental strata of the northern hemisphere, in which Callipteris conferta(Sternberg)Brongniart is the most famous represent...Callipterid is an important and highly heterogeneous group of fossil plants in the Permian continental strata of the northern hemisphere, in which Callipteris conferta(Sternberg)Brongniart is the most famous representative because its first appearance in the strata was considered as an index fossil for the beginning of the Permian terrestrial depos-展开更多
In order to get the correct isotopic age, SHRIMP U-Pb zircon date of Precambrian hornblende granite in Well TD2, located in the central aeromagnetic belt in the eastern of the Tarim basin, was carried out. The result ...In order to get the correct isotopic age, SHRIMP U-Pb zircon date of Precambrian hornblende granite in Well TD2, located in the central aeromagnetic belt in the eastern of the Tarim basin, was carried out. The result showed a dependable age of 1908.2 ± 8.6 Ma, which demonstrated that the granite pluton is the result of the magmatic activity in early Palaeoproterozoic. It is indicated that the central aeromagnetic belt across Tarim basin, divided it into north and south block, is formed before Neoproterozoic by a large scale tectonothermal events based on the seismic and drilling date. The Tarim continent may have different age and type basements formed the united crystalline basement in Precambrian. This result has yielded new intraplate evidence to constrain the relation between the Tarim plate and the Colombia supercontinent.展开更多
本文应用化学蚀变指数(CIA)方法,研究新疆库鲁克塔格地区新元古代地层,并探讨沉积时期的气候环境。贝义西组总体 CIA 值较低,介于51～56之间,具冰期环境特征。照壁山组 CIA 值为60左右,表明气候有所变暖。阿勒通沟组的CIA 值变化范围在4...本文应用化学蚀变指数(CIA)方法,研究新疆库鲁克塔格地区新元古代地层,并探讨沉积时期的气候环境。贝义西组总体 CIA 值较低,介于51～56之间,具冰期环境特征。照壁山组 CIA 值为60左右,表明气候有所变暖。阿勒通沟组的CIA 值变化范围在48～61之间,顶部突变为69～71,说明阿勒通沟期经历了另一次寒冷事件,并以温暖环境结束。其上的特瑞爱肯组 CIA 值介于49～53之间,说明第三次经历寒冷干燥的气候环境。扎莫克提组,育肯沟组和水泉组的 CIA 均值为65,反映温暖条件下的沉积环境。新元古代末期汉格尔乔克组 CIA 值下降为56,暗示第四次出现寒冷气候环境。以上特征表明新疆库鲁克塔格地区新元古代的气候环境出现四次冷热交替变化。其中尤为重要的是阿勒通沟组中下部应为寒冷气候环境,而顶部突变为温暖气候环境,因此该组反映了一次明确的从冷到暖的气候变化过程,可以作为贝义西冰期和特瑞爱肯冰期之间的另一次独立冰期。本文的研究成果从地球化学角度支持塔里木板块新元古代四次冰期的划分方案。通过与扬子板块新元古代冰期划分方案的对比,认为塔里木板块新元古代四次冰期的前三次均已在华南板块以冰期或寒冷环境沉积形式出现。展开更多
基金Project 9487001 supported by the National Natural Science Foundation of Chinathe Analysis Centre of the Zhongguancun Distrjct of Beijing
文摘The relationships and boundary between the North China and Tarim plates have been unclear for a long time ; however, the two plates occupy a prominent position in the formation and evolution of the continental lithosphere of China. It is proposed that the Engger Us ophiolitic melange zone discovered recently north of Alaxa is a typical suture between the two plates. The ophiolitic melange zone is composed mainly of a mixture of fragments of ancient oceanic crust and sedimentary rocks of active and passive continental margins. The melange may be divided into tectonic inclusions and matrix. The suture extends northeastwards into the Republic of Mongolia and probably westwards to meet the Altun fault. With the Engger Us ophiolitic melange zone as the boundary the Alaxa area may be divided into two parts: the northern part (AN ) belongs to the Tarim plate, while the southern part (AS) the North China plate. Geological evidence shows that the two plates were amalgamated in the Late Permian or a bit later.
基金supported by the National Natura1 Science Foundation of China(Grant No.40032010).
文摘samples of limestones, mudrocks shales and tillites from the Sinian in Kuluketage have been analyzed. Four formations in the Sinian belong to glacial deposits in which the differences in d 13C are distinct (14.7‰—+4.2‰). Distinctly negative d 13C excursions for three times support the view of three glacial deposits in this area suggested by previous authors, except for the durations of them. d 13C values are generally positive in the Beiyixi Formation of lower part of the Lower Sinian, representing probably the rock records of a continental rift related to break-up of the Rodinian supercontinent. There are three times of distinct excursions of d 13C curve in all strata. The first one is from positive values at the bottom to about -5‰ at the top of the Beiyixi Formation. The second one, from 0‰—3‰ in the Arletonggou Formation of upper part of the Lower Sinian to 3.4‰— 14.4‰ in the Teruiaiken Formation. The third one, from positive values in the Zhamoketi Formation of lower part of the Upper Sinian to negative values in glacial varves at the top of the Hankeerqiaoke Formation.
文摘Callipterid is an important and highly heterogeneous group of fossil plants in the Permian continental strata of the northern hemisphere, in which Callipteris conferta(Sternberg)Brongniart is the most famous representative because its first appearance in the strata was considered as an index fossil for the beginning of the Permian terrestrial depos-
文摘In order to get the correct isotopic age, SHRIMP U-Pb zircon date of Precambrian hornblende granite in Well TD2, located in the central aeromagnetic belt in the eastern of the Tarim basin, was carried out. The result showed a dependable age of 1908.2 ± 8.6 Ma, which demonstrated that the granite pluton is the result of the magmatic activity in early Palaeoproterozoic. It is indicated that the central aeromagnetic belt across Tarim basin, divided it into north and south block, is formed before Neoproterozoic by a large scale tectonothermal events based on the seismic and drilling date. The Tarim continent may have different age and type basements formed the united crystalline basement in Precambrian. This result has yielded new intraplate evidence to constrain the relation between the Tarim plate and the Colombia supercontinent.
文摘本文应用化学蚀变指数(CIA)方法,研究新疆库鲁克塔格地区新元古代地层,并探讨沉积时期的气候环境。贝义西组总体 CIA 值较低,介于51～56之间,具冰期环境特征。照壁山组 CIA 值为60左右,表明气候有所变暖。阿勒通沟组的CIA 值变化范围在48～61之间,顶部突变为69～71,说明阿勒通沟期经历了另一次寒冷事件,并以温暖环境结束。其上的特瑞爱肯组 CIA 值介于49～53之间,说明第三次经历寒冷干燥的气候环境。扎莫克提组,育肯沟组和水泉组的 CIA 均值为65,反映温暖条件下的沉积环境。新元古代末期汉格尔乔克组 CIA 值下降为56,暗示第四次出现寒冷气候环境。以上特征表明新疆库鲁克塔格地区新元古代的气候环境出现四次冷热交替变化。其中尤为重要的是阿勒通沟组中下部应为寒冷气候环境,而顶部突变为温暖气候环境,因此该组反映了一次明确的从冷到暖的气候变化过程,可以作为贝义西冰期和特瑞爱肯冰期之间的另一次独立冰期。本文的研究成果从地球化学角度支持塔里木板块新元古代四次冰期的划分方案。通过与扬子板块新元古代冰期划分方案的对比,认为塔里木板块新元古代四次冰期的前三次均已在华南板块以冰期或寒冷环境沉积形式出现。
