Abstract: This paper discusses the distribution pattern and geological significance of the carbon and oxygen isotopes (δ13C and δ18O) in the depositional sequences of Gaoyuzhuangian, Yangzhuangian and Wumishanian ag...Abstract: This paper discusses the distribution pattern and geological significance of the carbon and oxygen isotopes (δ13C and δ18O) in the depositional sequences of Gaoyuzhuangian, Yangzhuangian and Wumishanian ages of the established Middle and Upper Proterozoic sequence stratigraphic framework in the Ming Tombs area lying in western Yanshan Mountain of Beijing. Besides, sketchy determination of δ13C and δ18O was also performed for other formations and members. The analytical results show the following: under the condition of clear-water carbonate sediments, δ13C and δ18O, featuring smaller variation of δ13C but larger variation of δ18O, can well delineate the relative change of sea level, which reflects the difference of primary sedimentary settings; in the presence of terrigenous substances, δ13C values vary greatly while δ18O slightly; the carbon and oxygen isotopes show marked changes at sequence boundaries. Besides, particular patterns can be found in regard to the distribution of carbon and oxygen isotopes within the sequences.展开更多
The Mesoproterozoic Changcheng System is widely distributed in the North China Craton. Determining its time of deposition and sources is important to understand the Precambrian crustal evolution of the North China Cra...The Mesoproterozoic Changcheng System is widely distributed in the North China Craton. Determining its time of deposition and sources is important to understand the Precambrian crustal evolution of the North China Craton. This paper suggests age distribution patterns for detrital zircons from clastic sediments of the Changcheng System in the Ming Tombs area, Beijing. Samples of feldspar-bearing sandstone (CHc-2) and pure sandstone (CHc-9) were collected from the Changzhougou Formation, which constitutes the basal part of the Changcheng System. Detrital zircons show an age range from 2.35 to 2.60 Ga. However, sample CHc-9 in the upper Changzhougou Formation also contains some zircons with ages of 1.9-1.8 Ga and 2.3-2.1 Ga. The age patterns lead to the following conclusions: (1) Most of the detrital material came from a source area composed predominantly of ~2.5 Ga continental crust of the North China Craton; (2) 1.9-1.8 Ga reflects the age record of Palaeoproterozoic continent-continent collisional event in the North China Craton; and (3) the oldest age for deposition of the Changcheng System is 1.8 Ga.展开更多
北京十三陵台站(Beijing Ming Tombs station,BMT)位于北京市昌平区十三陵镇德胜口村东北约600米处,隶属中国科学院地质与地球物理研究所空间环境探测实验室,是中国大陆地区最早实现数字化并率先进入国际地磁台网(INTERMAGNET)的观测站...北京十三陵台站(Beijing Ming Tombs station,BMT)位于北京市昌平区十三陵镇德胜口村东北约600米处,隶属中国科学院地质与地球物理研究所空间环境探测实验室,是中国大陆地区最早实现数字化并率先进入国际地磁台网(INTERMAGNET)的观测站。本数据集包含1991~2001年经过预处理后的北京十三陵台站的地磁观测数据,数据内容由磁偏角(D)、水平强度(H)和垂直强度(Z)三个要素的分钟值组成。本数据集可以用来开展地磁场、空间环境和地球各圈层耦合等方面的研究。展开更多
文摘Abstract: This paper discusses the distribution pattern and geological significance of the carbon and oxygen isotopes (δ13C and δ18O) in the depositional sequences of Gaoyuzhuangian, Yangzhuangian and Wumishanian ages of the established Middle and Upper Proterozoic sequence stratigraphic framework in the Ming Tombs area lying in western Yanshan Mountain of Beijing. Besides, sketchy determination of δ13C and δ18O was also performed for other formations and members. The analytical results show the following: under the condition of clear-water carbonate sediments, δ13C and δ18O, featuring smaller variation of δ13C but larger variation of δ18O, can well delineate the relative change of sea level, which reflects the difference of primary sedimentary settings; in the presence of terrigenous substances, δ13C values vary greatly while δ18O slightly; the carbon and oxygen isotopes show marked changes at sequence boundaries. Besides, particular patterns can be found in regard to the distribution of carbon and oxygen isotopes within the sequences.
基金supported by the National Seience Foundation of China(Grant No.40172044).
文摘The Mesoproterozoic Changcheng System is widely distributed in the North China Craton. Determining its time of deposition and sources is important to understand the Precambrian crustal evolution of the North China Craton. This paper suggests age distribution patterns for detrital zircons from clastic sediments of the Changcheng System in the Ming Tombs area, Beijing. Samples of feldspar-bearing sandstone (CHc-2) and pure sandstone (CHc-9) were collected from the Changzhougou Formation, which constitutes the basal part of the Changcheng System. Detrital zircons show an age range from 2.35 to 2.60 Ga. However, sample CHc-9 in the upper Changzhougou Formation also contains some zircons with ages of 1.9-1.8 Ga and 2.3-2.1 Ga. The age patterns lead to the following conclusions: (1) Most of the detrital material came from a source area composed predominantly of ~2.5 Ga continental crust of the North China Craton; (2) 1.9-1.8 Ga reflects the age record of Palaeoproterozoic continent-continent collisional event in the North China Craton; and (3) the oldest age for deposition of the Changcheng System is 1.8 Ga.
文摘北京十三陵台站(Beijing Ming Tombs station,BMT)位于北京市昌平区十三陵镇德胜口村东北约600米处,隶属中国科学院地质与地球物理研究所空间环境探测实验室,是中国大陆地区最早实现数字化并率先进入国际地磁台网(INTERMAGNET)的观测站。本数据集包含1991~2001年经过预处理后的北京十三陵台站的地磁观测数据,数据内容由磁偏角(D)、水平强度(H)和垂直强度(Z)三个要素的分钟值组成。本数据集可以用来开展地磁场、空间环境和地球各圈层耦合等方面的研究。
