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Zhou Y.,Peking University | Zhou Y.,Beijing Institute of Hydrogeology and Engineering Geology | Guo G.-X.,Beijing Institute of Hydrogeology and Engineering Geology | Zhang L.,Geological Survey Institute of Beijing | And 2 more authors.
Geology in China | Year: 2016

In this paper, a magnetostratigraphic sequence of drill hole was established on the basis of analyzing the deep drill hole data from the northern districts of Beijing plain, such as Changpin, Shunyi and Chaoyang, especially on analyzing magnetostratigraphy and pollen in Houshayu region. In combination with the research onthe activity of Nankou-Sunhe fault, Shunyi fault and Huangzhuang- Gaoliying fault, the authors determined Quaternary stratigraphic framework of Houshayu sag. The results shows that the bottom boundaries of lower Pleistocene, middle Pleistocene and upper Pleistocene of G3 drill hole are 511.7 m , 175.5 m, and 31.6 m respectively in Houshayu sag. In the late Yanshanian period, Houshayu sag was formed by the combined action of NE-trending Sunhe fault, NW-trending Nankou-sunhe fault and Huangzhuang-Gaoliying fault which controlled the western boundary of Beijing sag.In the Quaternary, the variability of the rate objectively reflects the characteristics of rise or fall of the blocks. Housahyu sag located in the hanging wall of the Huangzhuang-Gaoliying fault and the footwall of Shunyi fault were formed by the mutual movement between fracturesduring the Quaternary sedimentation, with the deposition rate of the sag in the early, middle and late Pleistocene being respectively 0.198mm/a, 0.255mm/a, and 0.243mm/a.

Jiang H.,China Earthquake Administration | Guo G.,Hydrogeology and Engineering Geology Team of Beijing | Cai X.,Geological Survey Institute of Beijing | Cai X.,Bureau of Mineral Resources | And 6 more authors.
Journal of Quaternary Science | Year: 2013

To reconstruct the history of climate and environment in East Asia during the Early Pleistocene, a palynofloral investigation was conducted on fluviolacustrine sediments in Beijing, North China. The results indicate that herb and shrub taxa were dominant in most of the samples, reflecting an open forest grassland covering the Beijing region during much of the Early Pleistocene. This vegetation generally declined during 1.68-1.25 Ma and recovered in part during 1.25-0.96 Ma. From 0.96 Ma, conifers gradually replaced broad-leaved trees, shrubs and herbs. After 0.65 Ma, the pollen abundance of conifers, shrubs and herbs all increased significantly. These vegetation changes took place in the context of long-term global cooling during the Late Cenozoic. A significant increase in Antarctic ice volume at 1.25-1.20 Ma and the resultant increased meridional temperature gradient in the Southern Ocean led to prominent anomalous warming in the tropics and increased heat/moisture flow across the Equator, probably resulting in vegetation recovery in the study area to some extent during 1.25-0.96 Ma. From 0.96 Ma, the stepwise decline of vegetation cover in the study area, especially after 0.65 Ma, was driven by further development of global cooling and increase in polar ice volume. © 2013 John Wiley & Sons, Ltd.

Zhao Y.,China University of Geosciences | Cai X.-M.,Geological Survey Institute of Beijing | Li Y.-L.,China University of Geosciences | Xu J.-X.,Geological Survey Institute of Beijing | Sun Y.-H.,Geological Survey Institute of Beijing
Kuangwu Yanshi/ Journal of Mineralogy and Petrology | Year: 2011

Based on the new data from some recent studies, the granitic batholith in Buyant area in the western part of northern margin of North China platform is composed of 4 granitic intrusive bodies of the Late Permian and the Late Triassic Period, with the emplacement age of 261 Ma± 1. 3 Ma, 220. 9 Ma±0. 3 Ma and 204. 9 Ma±5. 9 Ma respectively. The intrusive rocks consist of biotite granodiorite, porphyritic biotite granite and two-mica granite. Late Permian biotite granodiorite is characterized by mean Na 2O/K2O ratio of 2. 06, mean A /CNK contents of 1. 03 and mean σ contents of 1. 9,belonging to calc-alkaline series. The Late Triassic granite has an average Na2O/K2O ratio of 0. 82,mean A /CNK contents of 1. 03 and mean σ contents of 2. 18,belonging to calc-alkaline series. Petrochemical plots for diagnosing tectonic environments of rocks indicated that the Late Permian biotite granodiorite and the Late Triassic biotite granite were a series of island arc dioritoid and granitoid formed in the process of subduction. However,the Late Triassic two-mica granite was post-orogenic continental granitoid.

Luan Y.-B.,Bureau of Mineral Resources | Cai X.-M.,Bureau of Mineral Resources | Cai X.-M.,Geological Survey Institute of Beijing | Guo G.-X.,Beijing Hydrogeological and Geotechnical Party | And 2 more authors.
Geology in China | Year: 2011

Beijing Plain is composed of a suite of considerably thick alluvia and diluvia, and the establishment of the standard stratigraphie sequences of the whole plain is difficult because of the remarkable changes of lithology and lithofacies. With the rapid development of dating technology, the establishment of long dated sequences of sediments has become possible. Through observing the core of unconsolidated strata, this paper divided the core into 8 characteristic lithologie sections on the basis of the characteristics of sediment color, sedimentary environment, cycle and structure. Also, the result of paleomagnetism dating shows that 0-96.59 m of core is the Brunhes Normal Polarity Zone, 96.59-246.79 m is the Matuyama Reversed Polarity Zone, and 246.79-413.64 m is the Gauss Normal Polarity Zone. By mean of pollen analysis and a comparison with the evolution history of Cenozoic climate in North China, the authors hold that the depth of 246.5 m can be regarded as Q/N boundary, the depth of 534.5 m is N/E boundary, and the depth of 803.4 m is E/K boundary. Based on the principle of magnetic and climatic stratigraphy with the aid of rock stratigraphy, the authors studied the new No. 5 borehole and divided Cenozoic stratigraphie sequence into the late, middle and early Pleistocene, with Q/N boundary located at the depth of 248.4 m, N/E at the depth of 511.9 m, and E/K at the depth of 804.1 m.

Jiang H.,China Earthquake Administration | Guo G.,University of Chinese Academy of Sciences | Cai X.,Geological Survey Institute of Beijing | Cai X.,Bureau of Mineral Resources | And 3 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2016

The origin of lacustrine sediments in the middle latitudes of Asia remains controversial. In this study, we conducted major and trace element analyses on 86 lacustrine samples from the X5 core in Beijing to determine their origin and provenance. The results indicate that their abundances all varied in relatively narrow ranges, similar to those of the samples in the Chinese Loess Plateau (CLP). A high correlation of major and trace element abundances exists between our lacustrine samples and the CLP samples. UCC-normalized major and trace element abundances also have a similar pattern between the lacustrine and the CLP samples, with the exception of a few elements with high solubility, such as Mg. In the ternary diagrams of A-CN-K, La-Th-Sc and Zr/10-Th-Sc, and the correlation maps of major/trace elements and their ratios, four groups of the X5 lacustrine samples with different sedimentation stages (3.16-2.7Ma, 2.7-1.8 Ma, 1.8-0.9 Ma and 0.9-0 Ma) overlap well with each other and with the CLP samples, indicating that the X5 lacustrine samples are likely of windblown origin and possibly shared common, unchanged dust source regions with the CLP since the Late Pliocene. This interpretation is supported by the overlap of the lacustrine samples from Beijing with the CLP samples in the correlation maps of Ms vs. sorting, Ms vs. skewness, Ms vs. kurtosis, and kurtosis vs. skewness. Analysis of the frequency and cumulative frequency curves indicates that the X5 lacustrine sediments were dominantly transported by the winter monsoon and the westerly circulation. Given more scattered distributions of different elemental ratios and grain size parameters of the X5 core lacustrine sediments compared to those of the CLP samples, local dust particles must have contributed occasionally, which deserves further investigation in the future. Several chemical ratios, such as Rb/Sr, Na2O/Al2O3, CaO/Al2O3, and chemical index of alteration (CIA), were calculated for the lacustrine samples in Beijing. Comparison of these ratios' variations with those of the sea level of the South China Sea and the global benthic δ18O record indicates that Na2O/Al2O3 and CIA can be regarded as sensitive indicators of chemical weathering of lacustrine dust sediments in the mid-latitudes of Northern Hemisphere. © 2016 Elsevier B.V.

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