Yinshan Mountains Research Articles

The Region Gravity and Magnetic Anomaly Fields and the Deep Structure in Yinshan Mountains of Inner Mongolia

We have analyzed the distribution feature of Bouguer gravity anomalies in the Yinshan Mountains and its neighboring areas of Inner Mongolia. We find that this feature is in “synchronous” agreement with the elevation in the Yinshan Mountain, Daqing Mountain, and the Hu-Bao basin areas. On the aeromagnetic anomaly map, the Yinshan area is of large-scale negative anomalies and the Hu-Bao basin is of large-amplitude positive anomalies. Through analysis of earthquake, magnetotelluric, and gravity data, we establish a model of the crustal structure for the Yinshan Mountains and the Hu-Bao basin. The result shows that the lower boundary of the crust (Moho interface) below this region has no evident downward concave or upward convex shape. And the northern margin of the basin is presumably a contact zone between two large tectonic blocks. These structural characters can explain the causes of the special variations of gravity and magnetic anomalies in the Yinshan Mountains and the Hu-Bao basin.

ABSTRACT: Age, Style, and Regional Significance of Late Mesozoic Extension, Yinshan Mountains, China: Implications for Petroleum Systems in Northern Ordos Basin

ABSTRACT: Age, Style, and Regional Significance of Late Mesozoic Extension, Yinshan Mountains, China: Implications for Petroleum Systems in Northern Ordos Basin

The Early Precambrian Rocks, Their Ages, Division and Correlation of the Taihang‐Wutai Region, the Yanshan Region and the Eastern Sector of the Yinshan Mountains

Abstract According to differences of the protolith formations, the early Precambrian strata in the northern part of the North China platform may be divided into the stable stratigraphic region in the west and the mobile stratigraphic region in the east. Based on unconformities, either stratiragphic or tectonic, as well as significant metamorphic thermal events, the two regions may be stratigraphically defined as follows: 1) the middle Archaean Fuping Supergroup composed of the Chenzhuang and Wanzi Groups (stable areas), and the middle Archaean Qianxi Group (mobile area), whose upper limits are all dated at 2800 Ma; and 2) the upper Archaean Wutai Supergroup composed of the Longquanguan, Shizui and Taihuai Groups (stable areas), and the upper Archaean Zunhua, Dantazi and Zhuzhangzi Groups (mobile areas), whose upper limits are all dated at 2500 Ma. A correlation of the above‐mentioned units is also made. The lower Proterozoic Hutuo Group of the stable region is adjusted to comprise the Gaofan, Doucun, Dongye and Guojiazhai Groups. The upper limit of the Gaofan Group is placed at 2350 Ma, Dongye 1850 Ma and Guojiazhai (the lower limit of the Changcheng System) 1700 Ma.

Paleoplate tectonics between Cathaysia and Angaraland in inner Mongolia of China

On the basis of recent investigations in southern Inner Mongolia the authors consider that there are two Proterozoic rifts of E–W trend in the northern margin of the North China Platform. The Zhaertay Group and Baiyun'ebo Group of closed lagoon facies or neritic facies were deposited respectively in the two rifts. The lead isotopic dating of carbonaceous limestone from the middle sequence of Baiyun'ebo Group yields an age of 1500 Ma. Along the rifts a series of alkaline volcanics and intrusions is scattered in the Yinshan Mountains and Yanshan Mountains. To the north of the rifts, four ophiolite belts and at least five accreted terranes of various ages have been recognized in the Paleozoic orogenic zone. The presence of the ophiolite suites and these accreted suspect terranes in Inner Mongolia indicates that probably there was an open ocean between Siberia and North China in Paleozoic times, when repeated subduction of the oceanic crust had occurred along both continental margins. The suture line between Cathaysia and Angaraland extends from Linxi to Solon Obo. In the late Permian, epicontinental mountain systems of the two converging continents collided with each other. From the analysis of the tectonic evolution of Inner Mongolia and adjacent areas we conclude that the evolution of the southern margin of the Siberian Platform is approximately the same as the history of activity of the trench‐arc‐basin system in the eastern Asian epicontinental areas during Mesozoic and Cenozoic times but the northern margin of the North China Platform is similar in evolution to the Cordilleran system in western North America.