2013 Vol. 19, No. 1

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DISCUSSION ON THE EPOCH OF LACUSTRINE STRATA IN TOGTOH, INNER MONGOLIA
JIANG Fu-chu, FU Jian-li, WANG Shu-bing, LI Chao-zhu
2013, 19(1): 1-13.
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A set of later Quaternary fluvial-lacustrine strata is widely distributed in the Hetao region, which is compared with Salawusu Formation by predecessors. The Togtoh mesa is located in the east of the Hetao plain, and forms the geomorphic second platform. The lacustrine strata are well-exposed along the east bank of the Yellow River at the front edge of Togtoh mesa. The article mainly studied on the age of Haojiayao section and Haojiayao drill core section by lithological description as well as OSL and ESR dating methods. The emergence stratum of Haojiayao section is 47 m thick, the age at the top of lacustrine formation is about 106 kaBP, and the bottom is about 150 kaBP. Base on the lithological character, the Haojiayao drill core section can be divided to three parts:0~12.77 m is a set of brownish yellow silty clay and clayey silt layers, which should be the Late Pleistocene Malan Loess, and its OSL age is 106~40 kaBP; 12.77~70.23 m is a set of chartreuse, taupe silt and silty clay layers which should be lacustrine deposition, with OSL age being about 400~106 kaBP which belongs to Late Pleistocene; 70.23~118.45 m is a set of brownish red silty clay layers with calcareous interlayers, that should be the eolian loess which was influenced by water, its ESR age is about 476~990 kaBP, and corresponds to the Middle Pleistocene Lishi Loess. The Togtoh lacustrine strata should not belong to the Salawusu Formation, because of the large differences between the age of classic Salawusu Formation and the Salawusu river basin which is about 75~150 kaBP.
DRY-HOT CLIMATE CHANGES FROM 210 TO 120 kaBP BY LACUSTRINE SEDIMENTS IN YUANMOU BASIN, YUNNAN
LI Hua-yong, MING Qing-zhong, ZHANG Hu-cai, SU Huai, ZHANG Zi-qiang, DUAN Li-zeng
2013, 19(1): 14-25.
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Langbapu Palaeolake is located in the west of Yuanmou Basin. A complete lacustrine sediments stratum (27m-thick) was preserved and the ESR dating was accomplished in this paper. The research results showed that Langbapu Lake existed from 216±20 to 121±10 kaBP, which covered the end of the penultimate interglacial, the penultimate glaciation as well as the beginning of the last interglacial. Based on the analysis of grain size, magnetic susceptibility and pollen, the palaeoclimatic changes during 216±20 and 121±10 kaBP of Yuanmou Basin has been reconstructed. During 216~185 kaBP, the mean pollen concentration was the highest and Cycadaceae and Cyperaceae, as well as Sedge vegetation appeared, which indicated that the climate was relatively hygrothermal. During 185~150 kaBP, the pollen concentration decreased rapidly. In the 160 kaBP, the pollen concentration was only 8.67 grain/100 g, which was corresponding to the glacial maximum of penultimate glaciation. During 150~122 kaBP, several sandy gravel layers appeared. The proportion of herb increased. The palaeoclimate became warmer but drier, which was very similar to today's climate. The Langbapu Lake shrank and disappeared at last. The mean pollen concentration of lake sediments was only 34.35 grain/100 g, so we thought that dry-hot climate was already significantly before the penultimate interglacial. The characteristics of dry-hot climate were very similar to modern status after the last interglacial.
CHEMICAL WEATHERING CHARACTERISTICS AND PALEOCLIMATIC SIGNIFICANCE OF THE EOLIAN DEPOSITS IN CHENGDU PLAIN
TAN Yuan-long, QIAO Yan-song, ZHAO Zhi-zhong, WANG Yan
2013, 19(1): 26-34.
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The chemical composition of the eolian deposits mainly depends on the material composition of the source area and post-depositional in-situ pedogenesis. In this study, systematic major element composition analysis has been made Shengli red earth section in Chengdu Plain, and compared with the geochemical characteristics of typical loess and paleosoil samples from western Sichuan Province. The research results show that, similar major element composition between the Chengdu Red Earth and the loess-paleosoil samples from western Sichuan, and they are also comparable to the average composition of the Upper Continental Crust. These suggest that the Chengdu Red Earth, as same as loess from western Sichuan, were all derived from well-mixed sedimentary protoliths which had undergone numerous upper crustal recycling processes. In the formation process of the Chengdu Red Earth, Ca and Na element experienced a large number of leaching and the content is very low, K and Mg also appeared different degree of leaching, explaining Chengdu Red Earth experienced chemical weathering process of plagioclase and potassium feldspar. Further study shows that, Chengdu clay has reached the later stage of medium degree of chemical weathering, and the vermiculated red soil has entered the strong weathering stage. From the chemical weathering parameters of the entire sequence, weakening chemical weathering intensity from 1.13 MaBP shows that Sichuan Basin and the surrounding area has gradually become drier since the mid-pleistocene, and has consistency with global climate change.
ANALYSIS ON GRAVEL FABRIC OF THE LATE CRETACEOUS TO THE PALEOCENE LIANHE FORMATION IN FUZHOU-CHONGREN BASIN, JIANGXI
LIANG Wei, CHEN Liu-qin, GUO Fu-sheng, JIANG Xing-bo
2013, 19(1): 35-44.
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Analyzing the gravel fabric of red layers of the Cenozoic in Ganhang tectonic belt is helpful to understand the formation and evolution of the red basin. Using analysis method to study the composition, particle size, shape and preferred orientations of conglomerate layers of the Late Cretaceous to the Paleocene Lianhe Formation in Fuzhou-Chongren basin. The study can estimate the source, origin and formation conditions of these gravels. The result shows that the gravels of the Late Cretaceous to the Paleocene Lianhe Formation were the products of alluvial fan facies in semiarid to arid climate condition. The gravel deposits are featured by multi-source and rapid accumulation, poor sorting, subangular to subrounded and low degree of weathering. The composition assemblages of gravels of different areas in the basin are obviously different, which reflects complex provenance condition around the basin. Based on the bed rock strata characteristics and the rose diagrams from the planes of maximum flat (ab-planes) of gravals, the sediment source was mainly from northern, northwestern and western parts of the basin.
DISCOVERY AND METALLOGENIC SIGNIFICANCE OF THE LATE CRETACOUS ADAKITES FROM ZETANG, TIBET
ZHAO Zhen, HU Dao-gong, LU Lu, WU Zhen-han
2013, 19(1): 45-52, 112.
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Adakites have an indicative significance to deep-seated structures of orogenic belt and thermal regime, and a closely relationship with the minralization of Cu and Au. The metallogenic mother rock of Sangbujiala skarn copper deposit, in Zetang, southern margin of the East Gangdise metallogenic belt is Late Cretaceous granodiorite. The major elements are characterized by higher SiO2 (>56%), Al2O3 (>15%), Na2O (≥ 3.5%) and K2O (>2%), lower MgO ( < 3%). Na2O/K2O is 1.03~1.43, with an average of 1.22. The analyzing results of race earth and trace elements show higher Sr (>400×10-6), lower Yb ( < 1.9×10-6) and Y ( < 15×10-6), higher Sr/Y (86.88~132.22, >20) and La/Yb (>10), enriched in LREE and depleted in HREE, and no negative anomalies of Eu, similar to those of adakite. By geochemical and geological characteristics, it was may be formed in partial melting of subduction oceanic plate of the O-type adakites, which interacted with mantle peridotite, showing that the southern margin of Gangdise has O-type adakites mineralization.
TRACE ELEMENT CHARACTERISTICS OF THE NO.47 VEIN IN DAKAITOU ORE DISTRICAT OF LINGLONG GOLD DEPOSIT
GAO Hai-dong, HU Bao-qun, LÜ Gu-xian, WU Ji-chun, GUO Tao, WANG Zhi-hua, WANG Nai-wei, LI Yuan-zhi
2013, 19(1): 53-62.
Abstract (207) HTML (86) PDF (9248KB)(6)
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After years of mining, the reserves of Jiaodong Linglong gold deposit have been consumed enormously. Therefore, the prospecting of reserve resources has become an urgent problem. In this paper, by using the application of rock geochemical method and choosing the typical ore 47 vein as the object of study, the trace elements related with Au had been tested and the correlation between trace elements and Au had been researched. Then, the concentration coefficient and axial zoning had been calculated and the indicative significance of trace elements to deep Au mineralization had been discussed. Finally, looking forward to some reference can be provided for the prospecting of Linglong gold deposit at depth. Some preliminary recognition as followed that the optimal indicator elements in gold ore body is Au, Ag, Bi, As, Cu, Co, Mo and Sb successively; the axial zonality sequence from top to bottom is As, Pb, Ag, Cu, Hg, Sb, Mo, Ni, Th, V, U, Mn, Zn, Bi, Co and Au; the enrichment coefficient of Au, Bi, Ag is big, Cu and Co is medium, Zn is of relative depletion; and the mineralization prospect of No.47 ore body is good in deep.
GECHEMICAL CHARACTERISTICS OF THE ELEMENTS IN XINCHENG GOLD DEPOSIT, JIAODONG PENINSULA
PENG Yong-ming, ZHAO Hai, GUO Chun-ying, WANG Xu-dong, XIA Rui, TIAN Yan-lin
2013, 19(1): 63-71.
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We made Au grade fractal distribution and multi-element cluster analysis to theⅠand Ⅴ gold ore bodies of the Xincheng gold deposit, and discussed their implication on superimposed mineralization. The Au grade of theⅠore body show multi-fractal distribution with fractal values at 2.2948 and 0.5845 which imply two stage superimposed mineralization. The Au grade of the Ⅴore body show single-fractal distribution with fractal value at 0.8831 which implies no superimposed mineralization. The multi-element cluster analysis shows that the Au has no obvious relation to other base metal elements, which indicate that the Au would be an independent mineralization event added by later Ag and other base metal mineralization. The Au grade fractal distribution and multi-element cluster analysis are all agree with previous studies on geological characters.
DIVISION OF SUBDUCTION-COLLISION SYSTEM IN THE EASTERN QAIDAM BASIN
YANG Li-Gong, LIU Ji-Shun, YU Huan-Tao, LIU Wen-Heng, YIN Li-Jun
2013, 19(1): 72-81.
Abstract (176) HTML (96) PDF (3826KB)(17)
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Based on the research fruits of southeastern margin NNW trending on Ela Mountain magmatic belt, in Qaidam by predecessors, combing with the elements of formation age, environment, structure, thermodynamic, gravity and magnetic geophysical anomaly for volcano-magmatite, ophiolite and sedimentary strata, we consider that the Ela Mountain magmatic arc was the production taking Songpan-Ganzi plate with the suture of A'nyemaqen Ophiolitic Belt as the northward closure. During the whole closing period, there was slippage in the in the bottom, and the shallow before colliding was the pattern of peninsulas+Aulacogen+oceanic. The tectonic movement experienced three stages of oceanic crust subduction reduction, intracontinental collision orogenesis and crust extension. The granite of research area started from oceanic crust subduction, developed in intracontinental collision, so it had dual character of I-S type granite, which is the geologic record of the tectonic movement in late Hercynian to early Yanshanian. With deducing the development process, the authors divided the collision system of magmatic belt in the southeastern margin of the Qaidam.
APPLICATION OF ASTER-GDEM DATA IN THE GEOMORPHIC CHARACTERISTICS ANALYSIS OF NORTHERN GREAT HIGGNAN LING MOUNTAINS
QIAN Cheng, CUI Tian-ri, LI Lin-chuan, CHEN Hui-jun, QIN Tao, LU Lu
2013, 19(1): 82-92.
Abstract (170) HTML (98) PDF (8961KB)(10)
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Based on ASTER-GDEM (30 m) data and geological information, adopting color-dye, density-class and GIS spatial analysis technology, the authors studied geomorphic characteristics of the northern Great Higgnan Ling Mountains by means of topography-elevation analysis, terrain-section analysis and hypsometric integral. According to the research results, the topographies of the present plain (plateau) and hills in the NNE-trending northern Great Higgnan Ling Mountains are the direct result of multi-stage uplifting. The range is strictly controlled by the NNE-trending regional faults activity, and then affected by the NW-trending faults activity. The northern Great Higgnan Ling Mountains have developed 5-level denudation-planation surfaces with different elevation, whose characteristics are different in the each area due to different erosion and tectonic activity. The NNE-trending faults activity is more obvious in the northern. The research of Hypsometric integral curve significantly suggests the late mature period of geomorphic evolution in the northern Great Higgnan Ling Mountains, because of tectonic uplift tending to stability stage, and a large number of long and narrow NW-trending valleys formed for the response of the NW-trending faults activity.
EARTHQUAKE RISK ANALYSIS IN THE ENGINEERING AREA OF BOHAI STRAIT CROSS-SEA CHANNEL
QI Jia-xiang, JI Hong-guang, PENG Hua, LI Huan-jun
2013, 19(1): 93-103.
Abstract (280) HTML (136) PDF (12205KB)(22)
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Spatial temporal features for regional historical earthquake of Bohai Strait area has been studied, and location and law of the earthquake been analyzed. We discussed the impact of the historical earthquake to the construction area, and provided a theoretical basis for the site choice of the Bohai Strait Cross-Sea Channel, so that the construction area could avoid active faults to the greatest extent, reduced the influence of earthquake to the Bohai Strait Cross-Sea Channel, increased the factor of engineering stable judgment, and made the evaluation more exactly and reliable.
GEOLOGICAL RADAR SURVEY AND STABILITY ANALYSIS OF ROCK SLOPE IN QIANLING MOUNTAIN
GUO Bin-bin, ZHAO Wei-hua, WANG Hong-cai, LI A-wei, SUN Dong-sheng
2013, 19(1): 104-112.
Abstract (141) HTML (89) PDF (6068KB)(17)
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Stability analysis of the high-steep rock slope focus in research and engineering sectors for a long time because it has been considered as the reason why geological disasters occurred such as slope instability and landslide. Taking the slope in Qianling Mountain in Fengtai District in Beijing as an example, parameters by rock mechanics experiment was obtained by combining with the real internal structure of rock mass which measured by geological radar. Geomechanical model of the slope has been established, and the safety factor was obtained through this model by the strength, and at the same time the whole evolutionary and the location of the critical failure surface can be found directly. Clearly, the applicability of this new method has practical value for the stability analysis of high-steep rock slopes.
SELECTION OF SOFT ROCK ROADWAY SUPPORTING METHODS IN THE WADONG COAL MINE
WANG De-bin, CAO Si-yun
2013, 19(1): 113-116.
Abstract (157) HTML (64) PDF (955KB)(16)
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Combining the practices from soft rock roadway supporting in Wadong Coal Mine, with analysis on the physical mechanic properties of the main coal-bearing layers and the engineering geological characteristics of the soft rocks, the authors pointed out that along with the increasing of exploitation depth, stress and deformation of adjacent rock of roadway obviously increased, which was the main factors influencing the selection of roadway layer and related supporting patterns. Therefore, an associated supporting pattern accord with the engineering geological characteristics of the adjacent rock should be selected.

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