Table of Content

20 February 2018, Volume 24 Issue 1

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In Situ Water Contents of Olivine from Combined Electron Backscatter Diffraction and Fourier Transform Infrared Analysis

YAN Haojie，WANGQin*

2018, 24(1):  1. 

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Water contents in olivine have significant effects on physical and chemical properties of the upper mantle. Water
concentration in nominally anhydrous minerals is mainly determined by Fourier transform infrared (FTIR) spectroscopy based on the
absorption coefficients of infrared light, which vary along different crystallographic directions in anisotropic minerals. Ideally, water
contents in olivine should be analyzed on oriented grains using the polarized infrared light. However, this method is very time
consuming because it requires mineral separation and orientation. Previous studies usually used unpolarized infrared light and
calculated the average water content of many olivine grains in a thin section by Paterson (1982) calibration. However, application of
unpolarized light assumes random orientation of mineral grains, which may underestimate water contents in olivine. Olivine in the
upper mantle often develops lattice preferred orientation. In order to obtain water contents in olivine in a more effective and accurate
way, this paper presents a new method to measure in situ water contents of olivine in a thin section using the combined electron
backscatter diffraction (EBSD) and FTIR analysis. Based on results of Bell et al. (2003), an ellipsoid of the water absorption coefficient(W) is established using W values along three crystallographic axes [100], [010] and [001]. Then based on the EBSD-derived orientation
of an olivine grain, the specific water absorption coefficient along a certain direction (Ws) in the ellipsoid is determined. Finally, water
content of the olivine grain is calculated using the Beer-Lambert equation. This method is applied to measure water concentration of
olivine from garnet peridotite xenoliths brought by Muskox kimberlites in the Slave Craton (Canada). The results demonstrate that this
method allows us to determine in situ water distribution of olivine in microscale and investigate the relationship between water contents
and fabrics of olivine.

Study on Chlorites and Uranium-source Minerals of Uraniumore- bearing Changjiang Granite in Southern Zhuguang Composite

ZHANG Li, SUN Liqiang, CHENWeifeng, FU Shuncheng, FU Hongning,GAOShuang,WEI Wenfang, SHEN Weizhou, LING Hongfei*

2018, 24(1):  13. 

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Changjiang granite is one of important uranium-ore-bearing granites in the southern Zhuguang granitic composite, northern
Guangdong province. In this paper, we present a systematical on mineralogical characteristics of chlorites and accessory minerals and
their alteration in the Changjiang granite, by using electron-microprobe analysis and scanning electron-microscope analysis. We found
that uranium mineralization was related to the chloritization of biotite by reducing-redox-state hydrothermal fluid in the
pre-mineralization stage. The chloritization of biotite altered the original U-bearing accessory minerals of the granite and formed new
U-bearing minerals such as coffinite near the chlorite. Uranium in the newly formed U-bearing minerals can be easily released into fluid
under circumstance of later hydrothermal fluid being in slightly oxidizing state in the mineralization stage. Accessory minerals in the
Changjiang granite include zircon, apatite, coffinite-thorite, uraninite and monazite. Among these accessory minerals, uraninite,
uranothorite and coffinite are thought of important uranium-source minerals of the Changjiang granite because of their high uraniumcontent that is readily released during later alterations by oxidizing fluids. Monazite has a moderate quantity of uranium that is
potentially able to be liberated when it is altered to synchsite. Such a process only occurs during chloritization of major minerals such as
biotite that enclosed the monazite. Therefore monazite is a potential uranium-source mineral. Zircon is not a uranium-source mineral
because uranium in zircon remains stable and not released even under hydrothermal alteration. Other minerals like allanite and apatite
have little uranium which is even below the detection limit of electron-microprobe, are thus not uranium-source minerals of the
Changjiang granite.

Species and Morphologies of Calcium Carbonates Induced by Bacteria under Shake and Static Culture

GUOWenwen, LI Fuchun*, ZHANG Chonghong

2018, 24(1):  33. 

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To better explore the effect of culture method (static and shake cultures) on species and morphologies of carbonate minerals
induced by bacteria, a batch of oscillatory experiments were carried out for a duration of 40 days in B4 medium under the mediation of
three kinds of bacteria-Bacillus cereus (strain GW-1), Lysinibacillus sp. ( strain GW-2) and Microbacterium sp. (strain GW-3). At the
same time, aseptic experiment without the inoculation was done as the control. The mineral species of carbonate were determined by
X-ray diffraction (XRD), and morphologies of precipitated carbonates were observed using scanning electron microscopy (SEM). The
results obtained under oscillatory incubation condition were compared with those obtained under static condition. The main results
were as follows: (1) All three bacterial strains could induce precipitate of calcium carbonate, but they had different abilities. Their
mineralization abilities were in the order of GW-2＞GW-1＞GW-3; (2) At the two culture methods, strains GW-1 and GW-2
induced the formation of calcite, while strain GW-3 mediated the formation of vaterite. The results suggested that bacterial specieswere the important factors affecting mineral species. Culture methods almost had no effect on mineral species; (3) The morphologies
of minerals induced by strains GW-1 and GW-2 were diversified with shake culture. However, single morphology existed in the
samples with static culture. The morphology of all minerals formed by strain GW-3 was spherical shape and was not related to the
culture methods used.

Zircon U-Pb Geochronology, Geochemistry and Tectonic Implications of the Tangbai Porphyritic Granite Pluton in Southern Margin of Gangdese, Tibet

WANGXuhui，LANG Xinghai*，DENGYulin，CUI Zhiwei，LOU Yuming，HAN Peng

2018, 24(1):  41. 

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In order to discuss the genesis of Late Triassic to Early Jurassic magmatic rocks and its relationship with the early-stage
evolution of the Neo-Tethys in the southern margin of the Gangdese, we report petrography, geochronology and geochemistry of the
porphyritic granites from Tangbai in southern margin of Gangdese, Tibet. Zircon U-Pb dating yields an age of (190.37 ± 0.87) Ma
(MSWD=0.58) for the porphyritic granites, indicating that they were formed in Early Jurassic. Geochemically, the rocks are
characterized by high contents of SiO2 (75.20%~75.97%), Na2O (3.39%~4.12%) and ratios of Na2O/K2O (1.40~2.00) and low contents of
MgO (0.32% ~0.38% ), thus can be grouped into calc-alkaline I-type granites. The trace elements are characterized by enrichment of
LILEs (such as Rb, U and K) and LREEs and depletion of HFSEs (such as Nb, Ta and Ti) and HREEs, indicating that they were formed
in magmatic arc setting related to the northward subduction of the Neo-Tethys oceanic slab. Furthermore, the granites have low Mg#values (26.71~41.34, Mean=35.26), and with Nb/Ta ratios similar to the lower crust, indicating that the granites were mainly generated
from partial melting of the lower crust. Combined with previous research results, it is shown that the Late Triassic to Early Jurassic
magmatic rocks in the southern Gangdese were formed in magmatic arc related to the northward subduction of the Neo-Tethys oceanic
slab, and the initial age of northward subduction of the Neo-Tethys oceanic crust should prior to the crystallization age (190.37±0.87 Ma)
of the porphyritic granites reported in this paper.

Geochemical Characteristics of the Loess in Nebraska, U.S.，and Their Paleoclimatic Implications

YANG Yang, ZHANG Hanzhi, LIU Lianwen*

2018, 24(1):  56. 

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Loess is one of the most extensive surficial geologic deposits in Nebraska, U.S.. The deposition rate of the Peoria Loess was
extremely fast during the last glacial period, especially in Bignell Hill, the Mass Accumulation Rate is highest in the word. It is still
controversial to interpret the cause of the mass dust in the central Great Plain. In this paper, the compositions of Nd-Sr isotopes, major,
trace elements and rare earth elements of the loess deposit were investigated on the Bignell Hill section in Nebraska. The results suggest
that chemical compositions of the Nebraska loess are relatively homogeneous. Compared with the upper continental crust and the
Luochuan loess in China, the contents of Fe and Mg are relatively low, and the contents of K and Na are relatively high in the Nebraska
loess. Nd-Sr isotopic compositions indicate there is another source with higher 87Sr/86Sr and lower εNd, except the primary provenance of
White River Group. The second source is likely to be glacial deposits which were derived from the area of Laurentide Ice Sheet, its
contribution even as high as 30%~45%. The chemical index of alteration of Nebraska loess is about 65.7, lower than Luochuan loess in
China, showing a weak chemical weathering intensity. The variation of CIA, Na/K and carbonate content in Bignell Hill section reveal a
dry and cold climatic condition and weak weathering during Peiria Loess deposit (25~18 ka). This climatic condition was beneficial to
the production and deposition of dust thus generated extremely high mass accumulation rate during that time.

Detrital Provenance of the Lower Jurassic Jinji Formation and Its Constrains to the Early Jurassic Geodynamic Background of South China

LIU Nian，JIANG Baoyu*，ZHOUXueyao，ZHOUWeiming

2018, 24(1):  65. 

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Early Mesozoic geodynamic background of the South China Block (SCB) is still controversial. The Late Triassic-Early
Jurassic Eastern Guangdong basin locates at southeastern margin of the SCB and contains key records of its geodynamic background.
Detrital zircon LA-ICP-MS dating was carried on the Lower Jurassic Jinji Formation in the basin in this study. The results display eight
age peaks, i.e. ca. 196 Ma, 247 Ma, 320 Ma, 432 Ma, 770 Ma, 1060 Ma, 1820 Ma, and 2430 Ma. Provenance analysis suggests that the
sources of the Lower Jurassic Jinji Formation were mainly derived from the northeast and north directions. Correlation of the detrital
zircon age spectra reflects that the studied basin resembles the Yongan basin to the northeast and Dongkeng basin to the north.
Integrated analysis of the sediment provenance, petrology and geochemistry of the Jinji Formation reveals that the Early Jurassic basins
in southeastern China, even though bear characteristics of passive continental margin, already received sediment supply from the
uplifts in more eastern region resulted from the northwestern subduction of the paleo-Pacific plate toward the SCB.

Major Controlling Factors of the Mesozoic Tectonic Deformation in the Erlian Basin: Physical Simulation and Discussion

XU Qiang, XU Fengyin*, ZHAO Yue, ZHAO Xin,HOUTao,WANGJianxin

2018, 24(1):  77. 

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The Erlian Basin is a Mesozoic oil-and gas-bearing basin in northeastern China. There are significant geometric and
kinematic similarities between the Erlian Basin and other Mesozoic rift basins in eastern China. According to the tectonic line of the
basin and the structure observed from the typical seismic profiles, the Erlian Basin consists of a central forward rift zone and peripheral
diagonal rift zones. Although a considerable amount of research has been carried out on the pre-tectonic control of the Mesozoic
deformation of the basin, the contemporaneous tectonic controlling factors remain unclear. In this study, three planar sandbox models
were designed to determine the major controlling factors by changing the extension rate, the extension direction, and the
syn-sedimentation. The results showed that the extensional direction controlled the internal fault characteristics of the rift. The ability
of the extension direction to control the fault characteristics increased with distance from the rift boundary. The rate of extension
changed the expansion of the weak tectonic zone and the scale of fracture development. Larger extension rates could lead to a largerand more complex fracture system. The syn-sedimentary action promoted the activity of the underlying slip-off layer, inhibited the
growth of the boundary fault, and thereby reversely promoted the development of internal secondary fractures. The experimental results
also showed that the extension direction was the major controlling factor of the tectonic deformation of the basin. The syn-sedimentation
and extension rate were the secondary controlling factors. Additionally, according to the geometric and kinematic similarity of typical
Mesozoic rift basins in eastern and adjacent areas of China, the study suggested a “southeastward extension” as a possible kinematic
mechanism for the basin.

Luminescence Properties of Quartz in the Sediments from Typical Chinese Rivers and Their Implications for Provenance

LIU Jianhui，JIANG Feng，CHENJie，SUN Qianli，CHENJing*，CHENZhongyuan

2018, 24(1):  88. 

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Quartz, one of the most widely distributed minerals on the earth surface, is believed to be the best carrier inheriting parent
rock information due to its strong resistance to weathering. The luminescence (thermoluminescence and optically stimulated
luminescence) sensitivity of quartz has been preliminarily tried to trace eolian sediment provenances since it is closely related to its
parent rock and transport-deposit processes. However, little is known about luminescence properties of quartz in the fluvial sediments.
The present study compares the luminescence properties of quartz derived from three important rivers of the eastern China (Huanghe，
Yangtze and Zhuoshui) and further discuss its possibility of tracing marine sediments. Through analysis of luminescence sensitivity of
quartz among 7 sediment size fractions (<4 μm, 4~16 μm, 16~32 μm, 32~45 μm, 45~63 μm, 63~90 μm, 90~125 μm) from Huanghe,Yangtze and Zhuoshui rivers, the results show that the luminescence sensitivities of 110℃ TL peak and OSL of quartz changed with
quartz grain size and the sensitivities of fine and coarse quartz grains are much lower than those of medium quartz (4~45 μm). It is also
found a significant difference of luminescence sensitivities in all quartz particle fractions among Huanghe, Yangtze and Zhuoshui
rivers, with the highest in Yangtze and the lowest in Zhuoshui River. The irradiation and bleaching experiments indicate that
transport-deposit processes might have increased the luminescence sensitivities of quartz to some degree. The quartz experienced more
irradiation and bleaching cycles in the Yangtze drainage basin because the transport time of sediments from source to sink was much
longer, which might lead to high luminescence sensitivities of quartz. Besides, the quartz generated from mafic igneous rocks in the
upper Yangtze also had high luminescence sensitivities. The luminescence sensitivities of quartz from Huanghe sediments inherit
quartz properties from Loess Plateau. As a short mountainous river, Zhuoshui River transported sediments quickly from source to the
sink, which resulted in low luminescence sensitivities of quartz due to less irradiation and bleaching cycles. In addition, metamorphic
rocks distributed widely in the drainage basin produced quartz with low luminescence sensitivities. Meanwhile, high luminescence
sensitivities of quartz with medium grain size were believed to the related to fluvial transport pathway and quartz properties. Although
increases in quartz luminescence sensitivities are predictable when fluvial sediments are transported in the sea, the increment might be
much less than the differences among the three rivers based on the above results. Therefore, quartz luminescence properties of 4~45
μm fraction are suggested to use for tracing marine sediments in the shelf of Yellow Sea and the East China Sea.

Geometric Features and Genetic Mechanism of Modern Mud Cracks in Dunhuang, Gansu

LIU Chuang,ZHONGJianhua,CAOMengchun, SUN Ningliang,HAOBing

2018, 24(1):  97. 

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Sedimentary structure is one of the mainelements of sedimentology. And mud cracks, which belong to the exposure related
structures, have been interested by scholars. In this study, mud cracks in Akesai River and Dang River, Dunhuang, Gansu were
classified according to shape characteristics and edge features of the polygon. Geometric features were characterized and the difference
of forming mechanisms was discussed for different types of mud cracks. The results show that there were rectangular, circular, irregular,
duplex and edge-curl mud cracks in Akesai River and Dang River, Dunhuang, Gansu. Temperature, sediments properties, the
differences between the upper and the lower, the salinity and biological activity influenced the formation of mud cracks. Moreover,
rectangular mud cracks tend to develop on the slope formation which was uncomfortable. The argillaceous sediments overlying siltstone
was usually thinner in the typical edge-curl mud cracks. The process of the mud crack development is divided into initial stage,
cracking stage, separation stage, and buckling stage. In addition, duplex mud cracks may be used to help understand changes in
palaeocurrent and palaeoclimate.

Effect of Fe2+ on Nitrate Reduction Using Zero-valent Iron

CHENHuan, ZHANG Yaping*, RUANXiaohong

2018, 24(1):  109. 

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Zero-valent iron(Fe0) was widely used for in-situ and ex-situ remediation of nitrate in groundwater, however, it remained to
be studied that how existing of Fe2+ worked in the reduction of nitrate by Fe0 which was covered by iron oxides. In this study, batch
experiments were conducted to investigate the effect of Fe2 + on NO3- reduction using 100 mesh untreated zero-valent iron (Fe0) as
reductant. The results showed that, Fe2+ could significantly enhance the removal rate and removal efficiency of NO3- in the presence of
Fe0, and the removal efficiency increased with elevated Fe2+ concentration; but the reaction experienced an initial stage of low rate due
to the existence of oxide film on the Fe0 surface. Fe2+ could directly revolved in the reaction and transformed Fe2O3 which covers the Fe0
to Fe3O4, which accelerates the transfer of electrons from Fe0 to NO3- and promote the reduction of nitrate. What’s more, the removal
efficiency of NO3- by Fe0 will be further improved while adding Fe3O4 into the reaction system, however, with the absence of Fe2+ , the
adding of Fe3O4 only will not influence the reduction efficiency by Fe0.

Microscopic Analysis of Sand Creep in High Pressure

YIN Jianhua,GUKai, JIANG Hongtao, LIU Chun, SHI Bin*, LIU Bing

2018, 24(1):  116. 

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The sand layers exhibit the characteristics of creep to some degree during the land subsidence. In this paper, we studied the
characteristics of sand deformation, using one-dimensional compression test under the condition of 4 MPa and extracted the
microstructure of sand by improving the test device. Through analyzing the creep characteristics and microstructures of 8 sand samples,
the following conclusions are obtained: sands with a single size have higher possibility to lead to sudden deformations and sands broken
which cause the slippage and position change of sands; The characteristics of deformation of sands are closely related to the grading of
sands which have higher possibility to cause more deformations and sudden changes when the sands size is large; Using the formal
factor of sands from micro-perspective to analyze the sands particles, we found that the smaller the formal factor of sands is, the higher
possibility of broken and the larger deformations of sands are.

Numerical Simulation of the Influence of Temperature Field on Slope Stability

ZHU Chenguang，LIU Chun*，SHI Bin，TANG Qiang

2018, 24(1):  122. 

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As the climate change , the property of rock and soil changes accordingly with environmental temperature changes. In this
paper, the influence of temperature field on the stability of the slope by some manifestation mechanism. The direct shear test of cohesive
soil under different temperature conditions is carried out to explore the change law of cohesion and internal friction angle. Furthermore，
combine ANSYS （finite element software） with the measured geothermal data to simulate the evolution temperature field of slope.
According to the field of temperature , cohesion field is calculated which can find distribution of the safety factor by using optimized
swedish method. Through a series of laboratory tests, it is found that the cohesive force of Xiashu is affected by temperature. Soil
moisture content and density affect the soil showing thermal consolidation or thermal softening phenomenon. The evolution in
temperature field of slope is simulated by ANSYS during the high temperature in summer of Nanjing suburb. The variation law of slope
stability index is deduced. The results show that the slope stability is lower in summer hot temperature environment, and the safety factor
of urban slope is lower. The heat island environment has a negative effect on the stability of slope.

Influence of Heterogeneity of Sandy Carrier Bed of Littoral Facies on Hydrocarbon Migration and Accumulation: A Case of the Donghe Sandstone in the Hadexun Area, Tarim Basin, China

WANGTao,XUHuaimin*，JIANGTongwen,CHENXuanhua,LIUTaixun,FANGHuijing，HANRubing

2018, 24(1):  128. 

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To understand the influence of heterogeneity of sandy carrier bed of littoral facies on hydrocarbon migration and
accumulation, a case study of the Donghe sandstone in the Hadexun area, Tarim Basin was conducted in this paper. The heterogeneous
structure of the carrier bed was divided into nine grades based on the study of sedimentary architecture. The heterogeneity of grades 7
and 8 were further investigated through the outcrop description and core physical property analyses. In the same grade, heterogeneity
types of carrier bed were divided into structural heterogeneity and physical property heterogeneity. The heterogeneity of carrier bed and
fluid differentiation have an obviously corresponding relation. Numerical simulation shows the dynamic process of hydrocarbon migration and accumulation in the sandy carrier bed of littoral facies has heterogeneity, both temporally and spatially. This results in
the complicated oil-water relationship, which is the major cause of the inclined oil-water interface. The heterogeneity influences the
process of hydrocarbon migration and accumulation from paleo-oil pools to new traps in five stages: migration initialization, migration
adjustment, migration stabilization, accumulation initialization and accumulation completion. Two processes and five stages occur in
different positions of carrier bed.

A New Method for Predicting the Development Range of Abnormal High Pressure: A Case Study in the Dongying Sag

ZHANG Shouchun,WANGXuejun, ZHU Rifang, QIU Yibo

2018, 24(1):  139. 

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Abnormal pressure is one of the critical issues in oil-gas reservoir formation, and its development range indicates the main
direction of oil-gas migration and thus is important to the prediction of favorable exploration areas. Based on a case study in the
Dongying sag, a new method for the prediction of abnormal pressuredevelopment range is established by using hydrocarbon
geochemistry. First, combined the measured pressure with the geophysical data, the present pressure development characteristics in the
Dongying sag were analyzed to determine the division and scope of pressure systems. Second, according to the statistical features of
hydrocarbon geochemical parameters within the pressure systems, their relationship with pressure development were analyzed. Results
show that the sterane C29S/R, sterane C27/C29 and Pr/Ph ratios are positively correlated to pressure coefficient in abnormally high
pressure zones. Geochemical parameters were screened for the division of abnormally high pressure zones and the correspondingvalue
rangeswere determined. This new methodology was further applied in the Dongying sag. Results show that the development scope of
abnormally high pressure is larger than the present abnormally high pressure zone either horizontally or vertically. The main extension
areas locate in the slope zone. This provides new important information for predicting favorable exploration targets.