Table of Content

20 March 2015, Volume 21 Issue 1

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Structural Evolution of the Youjiang Basin and Its Controlling Effects on the Formation of Carlin-type Gold Deposits

LIU Yin, HU Kai, HAN Shanchu, SUN Zehang

2015, 21(1):  1.  DOI: 10.16108/j.issn1006-7493.20141

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The Youjiang Basin, which is also named as the Nanpanjiang Basin, is an important enrichment area of Au-As-Hg-Sb
deposits in South China, and is also one of the largest enrichment area of Carlin-type gold deposits in China. The geological
characteristics of ore deposits indicate that the formation of these deposits has a relationship with the structures. Therefore, detailed
discussions on the structural characteristics and tectonic evolution of the Youjiang Basin are important for understanding the
development history of gold deposits. Combined with the previous studies, we think that two main sets of structures were developed in
the Youjiang Basin including the NW-and NE-trending ones; The NW-and NE-trending boundary faults played an important role in the
evolution of the basin and the distribution of volcanic rocks; All gold deposits are distributed in the basin， and the lithology and

structures are the two main factors that control the formation of gold deposits; Evolution of the Youjiang Basin can be divided into six
stages, i.e., the shore-shallow sea shelf development stage in the middle of Early Devonian (D12); the rifted ocean basin development
stage during the Middle Devonian to the Middle Permian (D2-P2); the ocean basin disappearance and foreland basin development stage
during the end of Middle Permian to the Middle Triassic (P23-T2); the stage of foreland basin disappearence and post-collision extension
during the Late Triassic to the Early Jurassic (T3-J1); the NE-trending compression structure development stage during the Middle
Jurassic to the middle of Early Cretaceous (J2-K12); and the partly extension stage during the late Early Cretaceous to the Paleogene.
The Carlin-type gold deposits were possibly developed after the foreland basin disappeared, and the ore-forming stage was related to the
extensional tectonic environment.

Geochronology and Geochemistry of Volcanic Rocks in the Lishui Basin in the Middle and Lower Reaches of Yangtze River and its Geological Implications

ZHANG Shaoqin, WANG Lijuan ,YANG Yinghe

2015, 21(1):  15.  DOI: 10.16108/j.issn1006-7493.20141

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The Lishui Basin is located in the eastern part of the middle and lower reaches of Yangtze River metallogenic belt. It is
similar to the Luzong and Ningwu basins, where Mesozoic volcanic rocks are widespread. In order to investigate the formation time,
magma source and tectonic background of volcanic rocks in different cycles and their relationships with the Fe-Cu mineralization, this
study presents the new zircon dating results, Hf isotopic compositions, and major and trace element analysis of widely exposed
Longwangshan and Dawangshan volcanic rocks which are mostly related to mineralization of Lishui Basin. It is suggested that the
magmatism began at ~135 Ma, and peaked at 135~124 Ma in the Lishui Basin. Zircons from the Longwangshan and Dawangshan
volcanic rocks have similar Hf isotopic characteristics with εHf(t) values of -6~-11, suggesting similar magma sources. The
geochemistry characteristics suggest that the compositions of magma range from intermediate-basic to intermediate-felsic and rich

alkali, and the distribution of outcrops from NW to SE from Longwangshan Formation to Dawangshan Formation, which is related to the
iron, copper, gold, and strontium deposits. The positive anomaly of Sr of the Longwangshan volcanic rocks suggests that they could be
the source of the Sr deposit. Combined with the geochemical and isotopic characteristics, it is suggested that these magmatic rocks were
probably derived from an enriched mantle, which was contaminated by minor crustal materials during eruption. The formation time and
tectonic setting of the Lishui Basin is similar to those of the other volcanic basins along the middle and lower reaches of the Yangtze
River, suggesting that they could be controlled by the same tectonic background. Based on analysis of previous studies, this study
confirmed that the change of the subduction of the Pacific Plate occurred at ~135 Ma, when subduction weakened, and subsequently
the subducted slab rollback occurred, and finally formed regional extensional environment, resulting in the formation of a series of
volcanic basins.

Geological Characteristics and Research Significance of Igneous Rocks in the Integrated Exploration Area of Zhaxikang, South Tibet

LAI Yang，ZHOU Qing，QIN Jianhua，XIA Xiangbiao，WU Jianyang，LI Yingxu

2015, 21(1):  31.  DOI: 10.16108/j.issn1006-7493.20141

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Igneous rocks are very important to study the regional geological setting and the origin of the metal ore deposits. The
magmatic activities were very strong in South Tibet in response to the collision of India plate and the Eurasia continent. However, there
is limited report on igneous rocks emplaced in the Tethys-Himalaya antimony-gold metallogenic belt, especially in its eastern part,
which was near the MCT. Previous studies indicate that the origin of these deposits was related to the magmas. The integrated
exploration area of zhaxikang lead-zinc deposit is located in the eastern part of the metallogenic belt. Recently, we have found
considerable bimodal plutons or dykes in this area. This result is beneficial to study the magmatic activities and tectonic evolution as
well as the origin of related ore deposits. In addition, it provides basic data for investigating metallogenic models as well as ore
prospecting models in North Himalaya.

Calculation of pH for Common Aqueous Fluid Inclusion Systems

ZHANG Yuesha, MAO Shide*

2015, 21(1):  43.  DOI: 10.16108/j.issn1006-7493.20140

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Common ore-forming fluid systems can be approximated as a CO2-H2O-NaCl system or its subsystems. Once the ore-forming
fluids are trapped and sealed by minerals during the ore-forming process, fluid inclusions will form. Physicochemical parameters of the
ore-forming fluids, such as temperature, pressure and composition, can be obtained by the thermodynamic studies of fluid inclusions.
Although pH is an important physicochemical parameter, the pH study of fluid inclusions is still at the primary stage. Up to now, only a
few researchers measured the pH of CO2-H2O-NaCl system, and some researchers developed the thermodynamic models to calculate the
pH of this system. Combining with the previous work, we systematically summarize the pH calculation models of the important fluid
inclusion systems (H2O, NaCl-H2O and CO2-H2O-NaCl) and present an accurate calculation program for the relevant systems. in this
paper. The executable codes of the calculation programs for these systems can be obtained from this journal or the corresponding author.

Preliminary Study of REE Geochemistry of Copper and Iron Deposits in Yunnan Dahongshan

LI Jun, XIAO Bin*, FAN Yuhua, YANG Guangshu, QI Jindong, SUN Mingshu

2015, 21(1):  50.  DOI: 10.16108/j.issn1006-7493.20141

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This article focuses on the structures and geochemistry of veins that are typically cross-curring the Dahongshan copper and
iron ore deposits. Systematic sampling was conducted and the REE geochemistry of samples was analyzed. The results show that
(1) the mine in the region of various types of rock (ore) shows a decreasing trend in REE amount from mineralized tectonite, to ore, to
non-mineralized tectonite, which reflects differences in the degree of water-rock interactions between ore-forming fluids and rocks;
(2) the (La/Yb)N shows that LREE of similar tectonite in the mine displays large degree of fractionation, but different tectonites show
relatively uniform differentiation. LREE / HREE and (La/Yb)N ratio characteristics of the surrounding rocks, ore and tectonites indicate
that there is similarity in the degree of fractionation between LREE and HREE, suggesting that the REE of the ore-forming fluids is
inherited in certain rocks; (3) LREE / HREE (5.66~13.27) shows a gradual increase from formation of rock, tonon- mineralized
tectonite, to mineralized tectonite, to blocky and stripped ores, reflecting REE migration in the process of fracturing; The δEu of various

types of rock (ore) is greater than 1 and δCe shows a weak negative anomaly, suggesting that Dahongshan copper and iron ore
mineralization took place in a relatively oxidizing environment.

Characteristics and Geological Significance of Trace Elements from the Middle Permian Longge Formation Mudstones in the Jiaomuri Area, Qiangtang Basin

HUANG Jing, LI Qi*, HU Junjie, YANG Qiangqiang, GE Dongsheng, CHEN Ruoyu

2015, 21(1):  59.  DOI: 10.16108/j.issn1006-7493.20140

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Provenance analysis of sedimentary rocks has an important significance on revealing the composition of basins, qualities of
reservoirs and sedimentary environment. Trace elements of Middle Permian carbonaceous mudstone samples in Jiaomuri area,
Qiangtang Basin were analyzed and discussed. The study of trace element content，characteristic ratios and REE distribution indicates
that the samples are moderately differentiated in LREE((La/Sm)N=2.50~5.41), while the HREE shows flat pattern ((Gd/Yb)N=1.32~2.47)
and all samples have slight Eu abnormity. The ratios of Sr/Ba, V/Cr, Ni/Co, Ceanom and δEu values are used to reveal the redox of
paleo-ocean. Our data show that the Middle Permian sedimentary environment where mudstones deposited was mainly oxidizing marine
conditions. Ratio of Rb/Sr and La/Th-Hf, La/Sc-Co/Th, Th/Sc-Zr/Sc diagrams show that the provenance area underwent weak
weathering and the source rocks are probably mainly andesitic rocks. La/Sc-Ti/Zr，La-Th-Sc and Th-Sc-Zr/10 discrimination
diagrams suggesting that the carbonaceous mudstone of the Longge Formation formed probably in an oceanic island arc tectonic setting.

Geochemistry and Tectonic Setting of the Neoproterozoic Xiajiang Group in Jinping, Guizhou Province

MOU Jun, LUO Xiangjian*, WANG Anhua, ZHANG Housong, QIN Yongjun, LIU Tianqiang,

2015, 21(1):  68.  DOI: 10.16108/j.issn1006-7493.20140

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Based on the systematic sampling from the Neoproterozoic Xiajiang Group in the research area and the data analysis of
major elements and rare earth elements, this study shows that rocks had moderate quantities in SiO2, which its value ranged from 57.54×
10-2 to 88.91×10-2 with an average of 68.32×10-2, low content of CaO (generally smaller than 1%), and high concentration in K2O/Na2O
and Al2O3/TiO2 and low amount of TFe2O3+MgO. The ΣREE of total rare earth element is between 46.51×10-6 and 306.29×10-6 and its
average value was 152.46×10-6. ΣLREE/ΣHREE changed in 8.73~21.6, average value was 12.96, which indicated that it was rich in
LREE, loss in HREE. The δEu in each member of Xiajiang group ranged from 0.7 to 0.8, which was Weak negative anomaly. The REE
patterns were slightly to right. LREE had medium fractionation and HREE was low, which demonstated that the REE patterns was high
gradient in LREE and flat in HREE. Through the geochemistry parameter in each formation, it illustrated that it had similar
geochemistry features between Fanzhao and Qingshui formation, also Pinglue and Longli formation. It further illustrated that similar or
transitional structure background. It drew elementary conclusion that it was back-arc basin of active continental margin in Fanzhao and
Qingping stages, and edge marine sedimentary environment of continental margin in Pinglue and Longli stages.

 

Sedimentological Architecture of the Late Permian Carbonate Platform Margin to the West of Chengkou-Western Hubei Oceanic Trough, Sichuan, China

YANG Wei, ZHANG Tingshan*, WEI Guoqi, YANG Wei, LIU Mancang, LIU Zhiccheng

2015, 21(1):  79.  DOI: 10.16108/j.issn1006-7493.20141

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A analysis of detailed field observations drilling data, as well as paleontological, paleoecological, and stratigraphic
correlations were carried out to characterize the sedimentary facies and understand the evolution of the Changhsingian (Late Permian)
carbonate platform margin to the west of the Chengkou-Western Hubei Trough. These data demonstrate the constructive effects of the
sedimentation and ecology of the marginal skeletal reefs and the thrombolite mud mounded on the architecture of the carbonate
platform. The model of reef and shoal complexes rim carbonate platform in Changhsingian underwent a three-stages evolution: (1) the

slope break of the carbonate platform margin had not yet formed. The reefs and shoals were not fully developed, and the foreslope of the
platform was not especially steep; (2) The rim of the carbonate platform began to form. Skeletal reefs and shoal facies were developed in
vertical progradation-aggradation association sequences. The foreslope of the platform also became steeper; (3) The ecological niche of
metazoan was occupied by microbe in Late Changhsingian. The thrombolite mud mounds were formed at this time, when a vertical
aggradation sequence with the shoals developed on top of them. This fostered the further building up of the positive relief features of the
margin. Meanwhile, the platform margin became much steeper and slump breccia developed on the foreslope of the margin. The
ecological succession of reef-building organisms, together with changes in relative sea level, influenced and controlled the evolution of
the carbonate platform margin throughout the Changxingian Stage.

Research on Sedimentary Process and Characteristics of Hyperpycnal Flows

TAN Mingxuan, ZHU Xiaomin*, ZHU Shifa

2015, 21(1):  94.  DOI: 10.16108/j.issn1006-7493.20140

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Hyperpycnal flow, one of the most significant sediment delivery systems to deep water, has aroused a great concern for a
considerable number of marine geologists and sedimentologists in recent years. It is a kind of subaquatic flows which have higher
density than the ambient water (lakes or oceans) discharging from river mouth, and usually occurs during the flooding period of some
areas that lack of vegetation under extreme dry and hot climate. Hyperpycnal flows are sustained turbidity currents, containing
bed-loads and suspended-loads to transport sediments. They could vibrate frequently during the flowing process, but mainly wax
initially and wane later. Hyperpycnites are hyperpycnal flows deposits. The remarkable recognitions of hyperpycnites include vertical
composite rhythm, repetitive alternation of cross bedding and massive layers, organic matters, a large amount of plant debris and
internal scouring surfaces. The thickness of stacking ancient hyperpycnites vertically could be more than ten meters, and they also
behave as a point-source sand-rich or mud-rich submarine (sublacustrine) fan with channels, levees and lobes laterally. Hyperpycnites
could play crucial role in oil and gas geological merits and economic values because of extraordinary conditions to be high quality
reservoirs and could be rather promising exploring targets.

Acer Leaves and Samaras from the Late Miocene of Lincang, Yunnan Province

WANG Yunfeng, SHAO Yang, LI Binke, LIU Kenan, XIE Sanping*

2015, 21(1):  105.  DOI: 10.16108/j.issn1006-7493.20141

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Yunnan Province is a favorable place for investigation of plants diversity, floristic evolution and migration routes of
angiosperms. In this study, eight leaf impressions and seventeen winged fruits ofAcer from the upper Miocene Bangmai Formation of
Lincang, Yunnan Province were investigated. They are assigned into four species, including one new species-Acer lincangense sp. nov.
and one conformis-Acer cf. jingdongense. The occurrence of the genus Acer in the Bangmai Formation provides the evidence that the
Lincang flora was mixed with elements of the north temperate and paleotropical zones. And this character of Neogene floristic diversity
formed the basis of modern plant diversity in Yunnan Province. Furthermore, on the basis of statistical analysis of the number of fossil
species at different geological periods and extant species at present, the evolutionary history of the diversity of Acer can be divided into
three optimum phases, i.e., the Eocene, the Miocene and the post-Holocene. The diversity of Acer at species level is spirally increased
through the three evolutionary cycles.

Mineral Compositions and Brittleness of the Middle Jurassic Iacustrine Shale Reservoirin Northern Qaidam Basin

YUAN Yuan, JIANG Zhenxue, YU Chen, GUO Tianxu, SHEN Yushan, ZHAO Ruotong

2015, 21(1):  117.  DOI: 10.16108/j.issn1006-7493.20141

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X-ray diffraction (XRD) was used to qualitatively and quantitatively analyze Middle Jurassic lacustrine shale samples from
the northern Qaidam Basin. Results revealed that clay minerals were dominant with a range of 33%~79.7% and averaged in 54.3%.
Quartz mineral ranged from 14.5% to 57.8% with an average of 35.4%. Carbonate mineral ranged from 0 to 15%. Clay mineral
compositions show a middle diagenetic stage, corresponding to a mature evolutionary stage of hydrocarbons with a suitable maturity
condition for shale oil and gas formation. Three types of pores were found in the study area including intragranular pore, intergranular
pore, and marco fracture. Compared with marine shales, Middle Jurassic lacustrine shales in the northern Qaidam Basin have higher
content of clay minerals, less sensitive mineral, and relatively lower content of brittle minerals such as quartz and feldspar but can meet
criteria for the lacustrine shale gas reservoir exploitation. The average index of mineral brittleness was 42.6% suggesting a good

property of brittleness and compressibility which is good for fracturing.

Crude Oil Forming Processes and Exploration Significance of Carboniferous in Malang Sag, Santanghu Basin

WU Hongzhu, HUANG Zhilong, ZHANG Chenglin, TU Xiaoxian, LUO Quansheng,KONG Hongw

2015, 21(1):  124.  DOI: 10.16108/j.issn1006-7493.20141

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Crude oil and solid bitumen coexist in the volcanic reservoirs of the Well Ma25 in the Niuquanhu structure zone in the Malang
depression in the Santanghu Basin, Xingjiang. Through multistage separation and extraction, and geochemical analysis of the reservoirs,
the formation processes and exploration significance of these crude oil (or solid bitumen) have been discussed. The results show that the
crude oil / bitumen may mainly come from the source rocks of Lower Carboniferous, with lower Pr/Ph and gammacerane index, high
abundance of tricyclic terpane, high Ts/Tm ratio and the heavy aromatic component carbon isotope (δ13C>-28.0‰). Crude oil in the
reservoirs is now rich in biological degradation markers (25-norhopane) with no other significant biodegradation characteristics
(n-alkanes, steranes and hopanes is intact), reflecting the characteristics of the multi filling stages, that is, oil reservoirs suffered
biodegradation after accumulation in the Late Permian and were filled again in the Late Cretaceous. The existence of the Lower
Carboniferous source rocks in this area indicates that there are potentials for oil and gas exploration from reservoirs in the deep Lower
Carboniferous source rocks.

The Features of Fluid Inclusions in Reservoir and Petroleum Migration of the Carboniferous-Permian Strata in Middle Hefei Basin

CHEN Shunyong, YU Hao, LIN Chunming*, ZHANG Xia, QU Changwei, ZHANG Ni, NI Pei

2015, 21(1):  131.  DOI: 10.16108/j.issn1006-7493.20131

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Research about the Carboniferous-Permian reservoir in Hefei Basin with good petroleum potential is lacking. We mainly
discuss the petroleum migration features through petrology and microthermometry analysis of the widely developed fluid inclusions in
the well AnCan 1. The results show that the homogenization temperature of these aqueous inclusions in quartz micro-cracks and quartz
secondary enlargement edge are mainly at 145.2~150.2℃, 155.6~160℃ and 169.9~177.9℃ . Combined with the burial history-thermal
history, we speculate that the reservoir experienced three major oil and gas filling stages during 162.1~157.2 Ma (Late Jurassic). By

measuring the freezing point of inclusions，we study the salinity characteristics. According to the tectonic evolution and development
background of source rocks, we conclude that the petroleum migration mainly happened whthin the carboniferous-Permian strata. In
the meantime the deep hydrothermal of the Neoproterozoic-Lower Paleozoic may also move to the Carboniferous-Permian through deep
faults, and participated the migration and accumulation of oil and gas. Attention needs to paid to research on the hydrocarbon
accumulation of this area in the future.

Physical Properties Differences and Key Controlling Factors of the Clasolite Reservoirs and Carbonate Reservoirs in Tazhong Area

SHEN Weibing, PANG Xiongqi*, ZHANG Baoshou, HUO Zhipeng, WANG Gui

2015, 21(1):  138.  DOI: 10.16108/j.issn1006-7493.20140

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This paper reports data from observation of 55 wells and identification of more than 200 casting thin sections, mercury
injection data analysis and logging interpretation of 92 wells and analyzed physical properties differences between the Silurian-
Carboniferous clasolite reservoirs and the Ordovician carbonate reservoirs in the Tazhong area. Key controlling factors for the physical
properties differences were discussed based on geological setting. The results showed that the clasolite reservoirs have medium-low
porosity and medium-low permeability, and the carbonate reservoirs have lowto ultra-low porosity and lowto ultra-low permeability. The
correlations among porosity, permeability and pore-throat radius are totally different for the two different types of reservoirs. The
physical properties differences were controlled by sedimentation, which embodies sedimentary facies difference from macroscopic view

and minerals composition difference and grain size from microscopic perspective. Besides sedimentation, physical properties
differences are mainly controlled by compaction, dissolution, cementation and fracture rebuilding effect. Compared with the variation of
physical properties of clasolite reservoirs, the carbonate reservoirs are more likely affected by dissolution, cementation and fracture
rebuilding effect, and are more difficultly affected by compaction. Comparative studies of key controlling factors of the physical
properties show that clasolite reservoirs should focus on primary pore for petroleum exploration, while carbonate reservoir should on
secondary pore.

The Distribution Characteristics of Current Geothermal Field in Huainan Coalfield

REN Ziqiang, PENG Tao, SHEN Shuhao, ZHANG Haichao, XU Shengping, WU Jiwen

2015, 21(1):  147.  DOI: 10.16108/j.issn1006-7493.20141

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On the basis of systematically analyzing quantities of logging temperature data of surface boreholes and the measured temperature data of surrounding rocks of the underground roadway in Huainan Coalfield, and the measured thermal conductivity of 58 rock samples, this paper comprehensively investigates the current geothermal gradient and heat flow in this region. The study shows that the mode of current geothermal gradient in Huainan Coalfield is between 2.50°C/hm and 3.50°C/hm with an average of 2.9°C/hm. The heat flow value ranges from 31.87 mW/m2 to 83.9 mW/m2 with an average of 63.69 mW/m2. The geothermal gradient and the heat flow values are higher than that in Huaibei Coalfield. Heat flow is controlled by geothermal gradient obviously. The variation in geothermal distribution is similar to that of the distribution of geothermal gradient and, as a whole, it shows that the highest temperature occurs in the mid-east region, and the second highest temperature occurs in the west. The analysis shows that the distributions of current geothermal field and heat flow in the region are mainly controlled by regional geological background and regional tectonic framework.

Analyses of the Genesis of Tangshan Hot Spring Area in Nanjing

ZOU Pengfei,QIU Yang,WANG Caihui

2015, 21(1):  155.  DOI: 10.16108/j.issn1006-7493.20141

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Tangshan hot spring is one of the four great spa resorts of China. We conducted a systematic study to explore the genesis mechanism through a graphical method using a plot of dissolved silica versus enthalpy and a hydrogeochemical investigation, for the purpose of further exploration and sustainable use of the geothermal resources of this regon. The thermal reservoir temperature has been estimated to be 90°C, and the hydrochemical and isotopic compositions of the karst-geothermal water are different from those of the karst-cold water, pore water and surface water. Moreover, a higher temperature occurs in a deeper geothermal well than in a shallower well and less cold water is mixed in a deeper than a shallower well. Based on these data, a genesis model of the Tangshan hot spring has been postulated to be a low-medium temperature geothermal system of a convective type. The recharge area is located in the Tangshan mountain (known as Nanjing-Zhenjiang Ridge) as well as the Maoshan Ridge situated in the east of Jurong Basin, with a water circulation depth at 2.6~2.9 km. The geothermal water flows upward in Tangshan hot spring area through the Tangshan-Dongchangjie Fault in the intersection zones of the NW-and NE-striking faults.

Zircon SHRIMP U-Pb Dating and Geological Significance of the Weimen Group Tuffs From Mao County, Sichuan Province

BAI Fuzheng,WANG Yiwei,LUO Shaoqiang, LV Hang, MU Yonghong

2015, 21(1):  163.  DOI: 10.16108/j.issn1006-7493.20140

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The age of the Weimen Group that is exposed in Songpan-Ganzi (Sichuan) fold belt is of great interest. But so far there are no reports of its formation age. During a 1:250000 scale survey of Mianyang area, a nearly 100 m thick tuff bed in the Upper Weimen Group was identified and one sample was collected for high precision SHRIMP dating. A SHRIMP U-Pb weighted mean age of 530.1 ± 4.3 Ma (MSWD = 1.5) was obtained. The zircon Th / U ratios of the sample are from 0.36 to 1.09, and zircon grains show a clear oscillatory banding structure, indicating that zircons are of magmatic origin. The age results suggest that the Weimen Group was formed in the early Cambrian. The new age provides a chronologic basis for understanding the tectonic evolution of the Songpan-Ganzi fold belt.

Determination of Anaerobic Bacterial Consortia in Added Microbial Sources (Biogas Slurry) for Biogenic Methane Experiment

XIA Daping, WANG Zhen, SU Xianbo1,, SI Qing

2015, 21(1):  168.  DOI: 10.16108/j.issn1006-7493.20140

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Given that indigenous microbial consortia of raw coal samples are in great difficulty being separated, purificated and cultured, which are invariably at a big cost of time, biogas slurry was considered to be added as the microbial sources, of which the morphological characteristics and the amount of dominant anaerobic bacteria were determined prior to the conduction of biogenic-methane-production experiment. The results show that four types of anaerobic microbial consortia including fermentative bacteria, cellulolytic bacteria, sulfate-reducing bacteria and methanogens were separately indentified and observed with such recognizable morphological features as rod-shaped, spherical and streptobacteria; the gram-negative bacteria were found to be at a notable advantage after gram stain; further the content of microbial consortia determined by most probable number (MPN) counting method was deemed to be enough for following biogenic-methane-production experiment.

Geochemistry of Lanthanide and Yttrium in Coals from the Huaibei Coalfield: A Discussion on Influence of Magmatic Intrusion on the Distrbution of REE in Coals at Western Huagou, Huaibei

CHEN Jian, CHEN Ping, LIU Wenzhong, HU Youbiao

2015, 21(1):  172.  DOI: 10.16108/j.issn1006-7493.20141

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Liu et al. (2013, 2014) concluded that the abundance of REE in coals was increased during igneous intrusion that caused a secondary migration and enrichment of REE. However, some completely different conclusions could be reached from the same data provided by original authors. The concentrations of REY in the unaltered coal, thermally-altered coal, and intrusive rocks from the Huaibei coalfield were 118, 128, and 326 mg/kg, respectively. There was no significant difference in the REY concentrations between unaltered coal and thermally-altered coal, both of which were much lower than those of intrusive rocks. With regard to the upper continental crust-normalized REY patterns, the unaltered coal and thermally-altered coal shared a similar pattern and obviously differed from that of intrusive rocks, suggesting that the REY in the Huaibei coals was not affected by igneous intrusion. The LREY was more concentrated than MREY and HREY in the intrusive rocks; whereas the HREY was more enriched in coals than LREY and MREY. Therefore, the geochemistry of REE and yttrium suggests that REY should be divided into LREY, MREY, and HREY. Moreover, a similar geologic body (i.e., North American Shale, Upper Continental Crust, and common Chinese coals) to coals may be chosen as a standard for REY normalization.