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2017 Vol.36 Issue.3
Published 2017-09-25
655
Discovery of a new enantiornithine bird from Lower Cretaceous of western Liaoning, China
WEI Zhao-ying, LI Li
A new enantiornithine bird from Early Cretaceous Jiufotang Formation in Chaoyang of western Liaoning is described. This new small-sized bird shows several enantiornithine synapomorphies. Based on the morphological features of the hindlimb, this new specimen represents an arboreal enantiornithine bird. It has developmental forelimb and progressive coracoid, as well as lagging hindlimb and relatively primitive sternum morphology. The ratio of the length to the width of the sternum is approximately 1. Rostral margin of the sternum is rounded, the distal end of the outermost trabecula of the sternum is not expanded, and the distal end of the caudal trabecula is slightly expanded, with the keel of sternum absent. Its skeleton displays a mosaic of both primitive and derived characters, as well as the primitive sternum features. Its synthetic characters is distinguishable from other known small-sized enantiornithines, therefore this specimen represents a new genus and species:
Microenantiornis vulgaris
gen. et sp. nov.
2017 Vol. 36 (3): 655-662 [
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739
) [
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663
A new specimen of
Liaoceratops yanzigouensis
from Early Cretaceous Yixian Formation in western Liaoning
YANG Yu-qing, YIN Ya-lei, ZHOU Chang-fu, WU Wen-hao
A new specimen of
Liaoceratops yanzigouensis
is described from Lujiatun Bed of the Early Cretaceous Yixian Formation in Beipiao, western Liaoning. The specimen shows the typical characters of
Liaoceratops
:three premaxillary teeth; large triangular antorbital fossa; epijugal absent; predentary hooked dorsally; and ventral flange presents along the mandible with several tubercles. New morphological information of the rostral has been revealed through the three-dimensional reconstructions based on CT scanning, the rostral is keeled anteriorly and bears a broad vertical crest along its posterior midline. The postcranial skeleton of
Liaoceratops yanzigouensis
is described for the first time. The profile and position of the fourth trochanter is possibly valuable for the classification of the basal neoceratopsians.
2017 Vol. 36 (3): 663-670 [
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709
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743KB] (
638
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671
Petrogenesis and geological implication of Hongji Mountain muscovite granite in central and western Qiangtang, Tibet
ZHANG Le, DONG Yong-sheng
The muscovite granite has been found in Permian ophiolite melange, which intruded into gabbro and diabase dikes as vein in Hongji Mountain, central and western Qiangtang. The authors studied the petrology and geochemistry characteristics, with an emphasis on its petrogenesis and geological implication. Geochemically, the muscovite granite is silica-rich in composition, with high content of alkali (Na
2
O+K
2
O). It's peraluminous granite that belongs to the calc-alkaline series and is characterized by the enrichment of Th, Sr and the depletion of Nb, Ta, Zr, Ti. The chondrite-normalized REE distribution patterns are characterized by U-shaped pattern with intensely positive Eu anomaly. The petrology, geochemistry, element ratios and tectonic setting of muscovite granite are similar to obduction-type granites. The muscovite granite has low CaO/Na
2
O, high Al
2
O
3
/TiO
2
and low zircon saturation temperatures(T
Zr
), indicating it was probably generated by dehydration-melting of muscovite-rich pelite in a condition of low temperature fluid on the continental margin, while the ophiolite melange obducted onto continental crust. The discovery of Hongji Mountain muscovite granite indicates that the Paleo-Tethys had been closed, and north Qiangtang collided and converged with south Qiangtang.
2017 Vol. 36 (3): 671-681 [
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316
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756KB] (
1020
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682
Geochemical characteristics and tectonic setting of Bitu complex in northern West Junggar
YIN Shao-quan, ZHANG Bao-ke
Systematic petrological and geochemical analysis were conducted Late Silurian Bitu complex in northern West Junggar, with the attempt to reveal its petrogenesis and tectonic setting. The Bitu complex mainly consists of syenogranite and subordinate alkaline granite, syenite and diorite. The syenogranite and syenite are highly-fractionated I-type granitoids, characterized by low contents of MgO (0.3%~0.5%), CaO (0.8%~1.1%), high REE (105~204 μg/g) and strong Eu anomalies. The alkaline granite shows low Al
2
O
3
(9.9%), high total alkalis (6.8%) and REE (271 μg/g), strong depletion in Sr, Ba, Eu, with the affinity of A-type granite. The diorite exhibits high MgO (4.1%) and CaO (7.5%),and relatively high REE abundance (93 μg/g). It belongs to high-K calc-alkaline series and was formed by partial melting of H
2
O-rich mantle. Geochemical data suggest that granitic rocks of Bitu complex were originated from crystallization differentiation of partial melting juvenile crust. The Bitu complex is enriched in alkali, light rare earth elements and large ion igneous elements (such as Rb and K) and slightly depleted in Nb and Ta, indicating that it was generated in a post-collisional extensional setting.
2017 Vol. 36 (3): 682-690 [
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359
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726KB] (
720
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691
SHRIMP zircon U-Pb ages and geochemistry of monzonite in Duocaima,Tuotuohe area,Qiangtang
CHAO Wen-xin, LI Bi-le, YANG Wen-long, PENG Bo, NING Chuan-qi, GAO Xiong-wei
The Duocaima Pb-Zn deposit is located in the northeast margin of Qiangtang block of Qinghai.The authors undertook a detailed study of zircon U-Pb dating and geochemistry of the monzonite in Tuotuohe mining area.The results indicate that the monzonite is calc-alkaline to high-K calc-alkaline and aluminous,and is characterized by relatively high Na
2
O,low K
2
O and MgO.The samples have higher Rb/Sr(0.21~0.47),lower Nb/Ta(13.25~14.02),and low Mg
#
, etc.,indicating that the monzonite was derived from crust.The samples are enriched in LREE,LILE (e.g.,Rb,Ba,K,Sr),and active incompatible elements (e.g.,Th,U),and depleted in HFSE(e.g.,Nb,Ta,P,Ti),similar to the characteristics of volcanic arc magmas.The SHRIMP zircon U-Pb dating of the monzonite yields Late Cretaceous to Early Paleocene ages (65.8±1.1Ma).Combined with regional geological background,it is concluded that the monzonite was probably formed during the late stage of deep subduction of Tethys Oceanic Plate.
2017 Vol. 36 (3): 691-700 [
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351
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734KB] (
735
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701
Petrogenesis of Early Cretaceous Ailinyuan granites from northern-central Da Hinggan mountains: constraints from zircon U-Pb age, geochemistry and Hf isotopes
HE Yue, DONG Yu, HE Zhong-hua, ZHANG Yan-long, YANG Hao, WANG Qing-hai, CHEN Hui-jun
Zircon U-Pb geochronology, whole-rock geochemistry, and Lu-Hf isotope compositions were analyzed for the Ailinyuan granites in Chuoer area of Da Hinggan mountains. Ailinyuan pluton is composed mainly of monzogranite. Zircon U-Pb ages from two samples of 132 Ma and 137 Ma indicate that the Ailinyuan pluton formed in the Early Cretaceous. The geochemical data indicate that monzogranites are characterized by high SiO
2
and K
2
O, but low total Fe
2
O
3
and MgO, and moderate-weak negative europium anomalies with(Eu/Eu
*
)=0.46~1.07, ∑REE=54.11×10
-6
~191.42×10
-6
,LREE/HREE=11.38~18.03, with significant fractionation of HREE and LREE[(La/Yb)
N
=12.12~23.52]. The monzogranites show enrichment in large ion lithophile elements (e.g., Rb, Ba, K) and depletion in high field-strength elements (e.g., Nb, Ta, Ti) and P. Zircon Lu-Hf isotope characteristics show that the two zircon samples from these granites have positive
ε
Hf
(
t
) values of 3.9~7.9 and 2.9~8.0, respectively, and young Hf two-stage model ages of 709~942 Ma and 677~1 001 Ma, respectively. Combined with regional geology investigation, the authors suggested that the granitic magma was derived from partial melting of juvenile crustal material, possibly related to the subduction of the Paleo-Asian oceanic plate to the Xing'an Block.
2017 Vol. 36 (3): 701-713 [
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414
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822KB] (
752
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714
Formation mechanism of Baiyingaolao volcanic rocks in Wenbuqi area of Da Hinggan mountains
WANG Yang, XUN Zhong-yuan, LIU Zheng-hong, LI Shi-chao, WANG Shi-jie, DU Yang
The volcanic rocks in Baiyingaolao Formation of Wenbuqi area of Da Hinggan mountains are composed of a series felsic volcanic rocks such as rhyolite and rhyolitic lithic crystal tuff. LA-ICP-MS zircon U-Pb dating results show the rhyolite formed in the Early Cretaceous, aged in (131±1.5)Ma. The geochemical study suggests that the rhyolite is characterized by high SiO
2
(72.43%~78.64%), Al
2
O
3
(11.48%~14.24%), and K
2
O(4.09%~5.05%), and low MgO(0.14%~0.34%) in contents. Samples are significant in fractionation of HREE and LREE[(La/Yb)
N
=8.22~13.68], with negative Eu anomalies (
δ
Eu=0.39~0.90). The trace element are characterized evidently by enrichment of Rb, Ba, K, depletion of Nb,P,Ti. The ratios of
176
Hf/
177
Hf vary in 0.282 830~0.282 983 and the corresponding
ε
Hf
(
t
) values are positive ranging from 6.02 to 10.19. Above characteristics indicate that the volcanic rocks derived from the basic lower crust accreted from depleted mantle during Neoproterozoic. Tectonic setting is related to the extensional setting.
2017 Vol. 36 (3): 714-725 [
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399
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763KB] (
737
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726
Geochemical characteristics and geological significance of biotites from Bileashan alkali-feldspar granite of Tuohe forest farm in Da Hinggan mountains
JIN Rui-xiang, SUN Guo-sheng, FENG Hong-da, HE Xin, WANG Gang, ZHAO Tian-xue, LIU Cheng-xian
Based on the electron microprobe (EPMA) of biotites from Bileashan alkali-feldspar granite in the Da Hinggan mountains, the authors studied the chemical composition, genetic types, formation temperature and oxygen fugacity of biotites and discussed the characteristics and diagenetic background of magma sources. The studied biotites are characterized by high SiO
2
(39.876%~42.419%) and Mg(18.138%~20.02%), low FeO
t
(10.549%~11.468%), which belongs to Mg-biotites. The crystallization temperature of biotites ranges from 590℃ to 650℃, with high oxygen fugacity. Total Al ranges from 1.01 to 1.044 and Fe/(Mg+Fe) varies from 0.228 to 0.262, with Mg/(Mg+Fe
2+
+Mn) and FeO
t
/(FeO
t
+MgO) in the ranges of 0.673 to 0.834 and 0.345 to 0.387, respectively, suggesting magma source of Mg-riched lithospheric mantle, with contamination during the magma evolution.
2017 Vol. 36 (3): 726-733 [
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447
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717KB] (
741
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734
LA-ICP-MS zircon U-Pb dating, geochemical characteristics and geological significance of tonalitic gneisses from Banshigou area of southern Jilin
DU Chuan-ye, LIU Zheng-hong, LI Peng-chuan, GUAN Qing-bin, CHEN Xu
The authors discusse the origin and evolution mechanism of tonalitic gneisses from Banshigou area of southern Jilin. It is indicated that the TTG gneisses are characterized by high Si(SiO
2
=66.61%~72.35%), Al(Al
2
O
3
=13.56%~16.18%) and Na(Na
2
O=3.65%~4.69%), but low K(K
2
O=1.13%~2.25%). The chondrite normalized REE patterns are characterized by right inclining type. Trace element analysis shows the enrichment of large ion lithophile elements (e.g., Ba and Rb) and strong depletion in high field strength elements (e.g., Ni and Ta).The gneisses belong to the high aluminum TTG gneisses with geochemical characteristics similar to the high silicon adakite. LA-ICP-MS zircon U-Pb age data indicate that the rocks were crystallized at (2 619±28)Ma, so they are formed in Neoarchean. Zircon Lu-Hf isotopic analyses show that the magma is rarely mixed with the mantle material during its evolution, and the corresponding two-stage model age(T
DM2
) is mainly between 2 976 Ma and 2 675 Ma.Therefore, tonalitic gneisses of Banshigou area are probably produced by partial melting of basaltic oceanic crust in the subduction environment. The authors suggest that there probably existed an orogenic belt (Ji-Liao-Ji arc-continent collision orogenic belt) in Neoarchean in the northeast North China Craton.
2017 Vol. 36 (3): 734-750 [
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411
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1106KB] (
978
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751
Determination of Neoproterozoic meta-gabbro from Huanerku, Da Hinggan mountains and its geological significance
DU Bing-ying, FENG Zhi-qiang, LIU Yu-wei, ZHANG Tie-an, ZHAO Ming-sheng, ZHAO Yu-sheng, ZHEN Miao
Huanerku rock association in the Dayangqi forest farm of the Da Hinggan mountains, is composed of amphibolite, meta-gabbro, peridotite and marble, which mainly occurr as NE-trending layers, lens and pieces. LA-ICP-MS zircon U-Pb dating of meta-gabbro samples from the Huanerku rock association yields ages of (696.8±2.9)Ma. Geochemistry analysis shows that the meta-gabbro samples are similar to N-type mid-ocean ridge basalts (N-MORB), and are also with some features of island arc tholeiite (IAT), indicating that the formation of the meta-gabbro was affected by subduction. Integrating the data from the Jifeng and Gaxian ophiolite in adjacent regions, the authors suggest that the Huanerku rock association has an affinity with ophiolitic melange. The meta-gabbro may represent the remnant of Late Neoproterozoic oceanic crust, indicating that there was a palaeo-ocean basin in the northern Da Hinggan mountains.
2017 Vol. 36 (3): 751-762 [
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381
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1163KB] (
842
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763
Geochronological and geochemical characteristics of Neoarchean basement under Conozoic basalt in Changbai Mountain
ZHANG Hong-tao, ZHANG Xing-zhou, ZENG Zhen, LIU Yang, CUI Wei-long
The LA-ICPMS zircon U-Pb geochronological and geochemical analysis for granitic rocks and amphibolite gneiss exposed sporadically in the Quaternary basalt coverage area of Changbai Mountain show that the zircon U-Pb age of granitic rocks and amphibolite gneiss are 2 509~2 558 Ma and 2 475~2 553 Ma, respectively. Geochemically, both granitic rocks and amphibolite gneiss belong to tonalite-trondhjemite-granodiorite series (TTG). The REE pattern exhibits rightward sloping with significant fractionation of light rare earth elements (LREE) and heavy rare earth elements (HREE) (LREE/HREE=3.85~34.48). Muscovite monzonitic granite displays slightly negative Eu anomalies (
δ
Eu=0.41~0.54), enrichment of Rb, K, Th and strongly negative Nb, Sr, P, Ti anomalies. Biotite hornblende plagiogneiss shows negative Eu anomalies (
δ
Eu=0.67~0.76), enrichment of Rb, K, La, Nd and depletion of Th, Nb, Sr, P, Yb. Granitic gneiss and biotite plagiogneiss display slightly negative to positive Eu anomalies (
δ
Eu=0.87~3.3), enrichment of Rb, K, Sr and depletion of Nb, Th and P. Their geochronological and geochemical characteristics are similar to relevant rocks of the Baishan and Helong massifs, indicating the Baishan Block and Helong Block are the same block (Longgang block) during Late Archaean. Current distribution patterns of Baishan and Helong blocks are the results of reworking by the NE-trending left-lateral faults afterwards.
2017 Vol. 36 (3): 763-776 [
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277
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1482KB] (
817
)
777
Chemical composition and geological significance of biotites from monzonitic granite in Tuotuohe Saiduopugangri area in Qinghai
FENG Hong-da, SUN Guo-sheng, LU Da-chao, QU Yuan-xin, JIN Rui-xiang, HE Xin, LI Yang
Electron microprobe analyses (EMPA) demonstrate that biotites from the Saiduopugangri monzonitic granite in Tuotuohe area, Qinghai Province, are enriched in MgO, SiO
2
, (Na
2
O+K
2
O), but relatively depleted in Al
2
O
3
and FeO
t
, with the characteristics of high
M
(0.60~0.65), low ∑Al (1.30~1.39) and medium Fe/(Mg+Fe) (0.42~0.44), suggesting that they are Mg-biotites. The biotites crystallized at the temperature of 580℃ to 645℃ with high oxygen fugacity in the magmatic system. The compositions of biotites revel that the calc-alkaline granite formed in the orogenic background and the magma was from crust-mantle mixed source.
2017 Vol. 36 (3): 777-784 [
Abstract
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348
) [
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1KB] [
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652KB] (
809
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785
Geochemical characteristics and geological significance of garnet-mica schist in Gaojiapuzi silver deposit, Liaoning
ZHENG Yan, YANG Yan-chen, HAN Shi-jiong, YANG Yu
The garnet-mica schist is an important ore-hosting rock of the Gaojiapuzi silver deposit. The results of petrogeochemical analyses show that the garnet-mica schist has the characteristics of metamorphic rock, and is enriched in large ion lithophile elements (Th, K), depleted in high field strength elements (Nb, Ta, Ti), with relatively high total amount of rare earth elements (with ΣREE average value of 169.28×10
-6
). It also shows obvious fractionation of light and heavy rare earth elements, and is enriched in light rare earth elements, with a weak positive
δ
Ce anomaly and medium negative
δ
Eu anomaly. According to field observation and geochemical characteristics, the original rocks of garnet-mica schist in Gaojiapuzi silver mine are restored to mudstone, sandstone and miscellaneous sandstone, which show the characteristics of felsic materials from upper crust, and was formed in passive continental margin environment.
2017 Vol. 36 (3): 785-795 [
Abstract
] (
395
) [
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1KB] [
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797KB] (
1098
)
796
Zircon U-Pb dating, geochemical characteristics and geological significance of granite porphyry in Chenjiadian gold deposit of Heilongjiang
WANG Feng-bo, YANG Yan-chen, ZHANG Lin, NIE Shi-jia
The authors undertook zircon LA-ICP-MS U-Pb dating and studied the granite porphyry in geochemistry in Chenjiadian gold deposit of Heilongjiang. The age dating results show that the zircons from the granite porphyry yielded a
206
Pb/
238
U weighted mean age of (227±4)Ma. The geochemical characteristics of granite porphyry show that it is enriched in Si, Al and alkali, but depleted in Mg and Ca. The trace elements for granite porphyry are obviously enriched in HFSE (Th, Rb, K) and depleted in LILE (Ba, Sr, Ti), and rare elements show LREE-enriched, HREE-depleted, strong fractionation of LREE/HREE ([La/Yb]
N
=0.47~4.99) and strong negative anomaly of Eu (
δ
Eu=0.08~0.68). The discrimination diagrams indicate the granite porphyry is characterized by post-collision, which formed in post-collisional tectonic setting. Comprehensive results show the granite porphyry belongs to granite in S-type, formed in the orogenic setting of continental-continental collision after the closure of Paleo-Asian Ocean in Late Triassic. The Chenjiadian gold deposit is located in volcanic arc tectonic belt belongs to the Andean continental margin.
2017 Vol. 36 (3): 796-805 [
Abstract
] (
516
) [
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1KB] [
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781KB] (
771
)
806
Zircon U-Pb geochronology,geochemistry,petrogenesis and geological implications of host rocks of Gaosongshan gold deposit in northern Lesser Xing'an Range
LIU Yang, SUN Jing-gui, REN Liang, HAN Ji-long, WANG Qing-hai, GU A-lei, ZHAO Ke-qiang
Based on the study of geological characteristics of the deposit,the authors undertook zircon U-Pb dating and geochemical analysis of the representative trachyandesites in the host rock of the deposit,the results reveal:(1) six groups of single grained zircon U-Pb ages were obtained,of which ① is 2 422~2 683 Ma, for residual zircon ages, whereas ② to ⑤ are 606~943 Ma, 428~437 Ma, 281~303 Ma and 169~221 Ma, respectively, for captured zircon ages. The zircon age of ⑥ is 121~129 Ma, representing the formation of zircon in the processes of volcanism;(2) geochemical characteristics of major elements reveal that these volcanic rocks belong to high-potassium calc-alkaline series to shoshonite series;(3) trace elements and REE indicate that the rocks are characterized by enrichment of large ion-lithophile elements (LILE)(Rb,Ba,K, etc.) and light rare earth elements (LREE), but depletion of the HFSE elements (Nb,Ta,Ti, etc.) and heavy rare earth elements (HREE). Integrating all the relevant results,it is preliminary believed that there may exist a Paleoproterozoic-Neoarchaean basement or debris in the study area. The volcanism of this period was related to the partial melting of enriched mantle,magma intrusion and eruption in the tectonic background of lithospheric extension and thinning due to the subduction of the paleo Pacific Plate. The magma was contaminated by Early Jurassic intermediate-acidic intrusive rocks during the evolution process of rising. This magmatic activity is coincided with Early Cretaceous large-scale volcanic and magmatic events of Northeast China.
2017 Vol. 36 (3): 806-825 [
Abstract
] (
395
) [
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1KB] [
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1602KB] (
817
)
826
Characteristics of geology, fluid inclusions and genesis of Yingchengzi gold deposit in Ning'an, Heilongjiang
TANG Chen, ZHANG Xin-wen, SUN Jing-gui
Yingchengzi gold deposit is a typical epithermal deposit. To understand the mineralization condition of the deposit, integrating the geological characteristics of the deposit, the authors undertook microthermometry and laser-raman spectrum analysis on the fluid inclusions from the same gold-bearing quartz vein of different depths. The results show that the ore of Yingchengzi gold deposit is mostly alterated rock type, and the rest is quartz vein type. The mineralization processes can be devided into four phases:(I) Quartz-arsenopyrite-pyrite phase, (Ⅱ) Quartz-pyrite phase, (Ⅲ) Quartz-polymetallic sulfide phase and (IV) Quartz-sulfide phase. The fluid inclusions are mainly in gas-liquid phase,with the rest in single phrase of gas or liquid or in three phases. The homogenization temperature ranges from 247.9℃~400℃, salinity (
w
(NaCl)) ranges from 3.15%~7.70%, and the mineralization fluid density is 0.65 g/cm
3
~0.87 g/cm
3
. Combined with the data from inclusions laser-raman spectrum it is concluded that ore-forming fluid belongs to a medium to low temperature, medium to low salinity CO
2
-H
2
O-NaCl system. According to the results of thermometry, the pressure of ore-forming is 6~50 MPa, at depth of 0.11~0.65 km. Therefore it is concluded that the deposit is a medium temperature, medium pressure hydrothermal gold deposit related to ductile deformation. Combing the previous studies of metallogenic chronology, it is confirmed that the mineralization occured during the Asian oceanic crust subduction of Late Permian, and was related to the transformation of tectonic regime during continental collision of Songnen Massif and Jiamusi Massif.
2017 Vol. 36 (3): 826-835 [
Abstract
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405
) [
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1KB] [
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1009KB] (
879
)
836
Characteristics of fluid inclusions and genesis of Huanggoushan Pb-Zn deposit in Linjiang area, Jilin
TIAN Li-dan, SUN Feng-yue, WANG Li, LIU Jin-long, WU Qiong
In order to determine the ore-forming fluid and metallogenic mechanism of the Huanggoushan Pb-Zn deposit in Linjiang area, the authors undertook petrography, micro-thermometry and C-H-O-S-Pb stable isotope analysis of fluid inclusions in lead-zinc ores from the main metallogenic stage(polymetallic sulfide stage). The results show that the inclusions are gas-liquid two-phrase belonging to NaCl-H
2
O system. The main metallogenic stage's fluid is characterized by medium temperature(209℃~276℃), medium salinity(1.98~16.34wt%) and low density(0.79~0.96 g/cm
3
).Themetallogenic pressure ranges approximately from 16.8 to 33.0 MPa with depth mainly in 1.68~3.30 km. The hydrogen and oxygen isotope analysis indicate that the
δ
18
O
H
2
O
and
δ
D values are 3.3×10
-3
~9.9×10
-3
and -115×10
-3
~-74.8×10
-3
. Combining with the
δ
18
O-
δ
13
C diagram of carbon and oxygen isotopes, it can be concluded that the metallogenic fluids are mainly from mantle-derived fluids and may have mixed with the meteoric water. The
δ
34
S values of sulfur isotopes range from 2.6×10
-3
to 18.9×10
-3
, representing the enrichment of heavy sulfur. The
206
Pb/
204
Pb,
207
Pb/
204
Pb and
208
Pb/
204
Pb ratios of lead isotopes vary from 15.43 to 15.57,15.25 to 15.33 and 34.88 to 35.07, respectively, indicating that the metallogenic materials were derived from Zhenzhumen Formation, but does not rule out the mixing of materials from deep source. Combining with the regional geology, the deposit belongs to mesothermal vein-type lead-zinc deposit formed in the subduction background of the Paleo-Pacific Plate to the North China Plate, and the metallogenic age is the Late Yanshanian.
2017 Vol. 36 (3): 836-849 [
Abstract
] (
330
) [
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1KB] [
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920KB] (
874
)
850
New understanding of metallogenic regularities and prediction of Jilin Province
QI Cheng-dong, ZHANG Yong-huan, PENG Yu-jing, CHEN Er-zhen, NIU Jun-ping, QU Xu-jun, JIN Ke, WANG Chun-guang
Metallogenic epoch is one of the main weak points in the study of metallogenic regularity and prediction in Jilin Province. Study on the metallogenic epoch can not only enrich the study content of metallogenic regularity and prediction, which is helpful to scientific decision-making during field work and reduce the prospecting cost, but also promote new breakthroughs in mineral exploration. This study reached three conclusions through the interpretation of 19 cases, integrating new data and the regional mineral resources metallogenic evolution. The conclusions are as follows:①Taking the metallogenic epoch as the main axis, Jilin Province experienced three different stages of mineralization, i.e., "cratonization","Central Asia orogenic belt" and "Western Pacific continental margin volcano arc and basin ridge structure". ② The ore-controlling structure is represented by "structure controls the basin, the basin types control the phases and the phases control the deposits", "structure controls the magma, the magma controls the phases, and different phases form different ores", "structure controls the types, different types form different deposits, deposits determine the ore body". ③ During recent years, new findings of metallogenic epoch, new minerals, new types, new areas, and new concealed ore-bodies indicate that there is great prospecting potential in this area.
2017 Vol. 36 (3): 850-861 [
Abstract
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289
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1KB] [
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484KB] (
911
)
862
Rare earth element geochemical characteristics and geological significance of shale member in Middle Jurassic Shimengou Formation in Yuqia area of northern margin of Qaidam Basin
WANG Ke-bing, MENG Qing-tao, LIU Zhao-jun, SUN Ping-chang, XU Yin-bo, BAI Yue-yue
In this paper, the geochemical characteristics of REE from shale member of Shimengou Formation in Well YYY-1 have been analyzed, which illustrated the significance of paleoenvironment, paleoprovenance and paleoclimate, and revealed the impact on oil shale mineralization. The results show that the total content of REE(ΣREE)of shale member of Shimengou Formation varied from 139.16×10
-6
to 342.59×10
-6
with an average at 236.66×10
-6
, which is higher than the content of NASC and PASS. Geochemical parameters such as the ratios of ΣLREE/ΣHREE, (La/Yb)
N
indicate an obvious differentiation of ΣLREE and ΣHREE. The REE distribution patterns show that LREE is obviously richer than HREE. Geochemical parameters and La/Yb-ΣREE diagram suggest that the paleoprovenance was a mixture of sedimentary and volcanic rocks from the upper crust. Eu is obviously negative abnormality, indicating that the sediment was formed in anoxic environment suggesting that anoxic environment is in favour of the organic matter of oil shale enrichment. According to the high levels of ΣREE and
δ
Eu abnormal value, combined with previous research results based on sporopollen, the shale member of Shimengou Formation formed in the warm and humid climate conditions, which provided a good source of material and preservation conditions for the oil shale.
2017 Vol. 36 (3): 862-870,879 [
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348
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871
Industrial characteristics and development prospect of oil shale in Middle Jurassic Shimengou Formation in Yuqia area of northern margin of Qaidam Basin
XU Chuan, MENG Qing-tao, LIU Zhao-jun, SUN Ping-chang, LI Feng, BAI Yue-yue
Qaidam Basin is an important oil shale-bearing basin in Northwest China, and has great potential for oil shale in Yuqia area of northern margin. In order to find out the quality features of oil shale in the Middle Jurassic Shimengou Formation, systematic sampling, tests and analysis of Well YYY-1 in the study area have been carried out. All data show that the oil shale in the research area has the features of medium oil content, medium calorific value, high ash content, medium volatile, low moisture, low density and low sulfur. With its convenient transportation, good geological conditions and a series of industrial analysis indexes, the oil shale in Yuqia area is characterized by high quality, shallow burying depth and a high value of industrial development. It is suggested that an integrated industrial development process should be implemented in the oil shale-bearing areas in Yuqia, such as dry distillation refining, electric power generation, silica, and building materials. Integrated utilization project of oil shale in Yuqia area can be developed. This could alleviate the current energy shortage in Qaidam Basin, and also help to promote production of agricultural and animal huabandry in Qaidam area.
2017 Vol. 36 (3): 871-879 [
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340
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673KB] (
769
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880
Controlling effects on gas accumulation of volcanic reservoirs of Changling fault depression in Songliao Basin
LIU Zhe, SHAN Xuan-long, YI Jian, DAI Deng-liang
Volcanic gas reservoir is the important deep gas reservoir type of Changling fault depression in Songliao Basin. Based on the drilling core, SEM, porosity-permeability test and the analysis of plane porosity, the authors studied the types and characteristics of volcanic rock reservoirs, depicted the spatial distribution characteristics of volcanic rock reservoirs and gas accumulation by seismic data and production data, and explored the controlling effects of different volcanic rock reservoirs on gas accumulation. The results show that the study area mainly developed three types of volcanic rock reservoirs:porous rhyolite, rhyolitic tuff lava and blocky rhyolite reservoirs. The porous rhyolite reservoir is mainly with primary porosity and micro fractures, belonging to higher-highest porosity and low-higher permeability reservoir. The rhyolite tuff lava reservoir mainly developed devitrified pore and structural fractures, belonging to medium porosity and very low permeability reservoir. The blocky rhyolite reservoir mainly developed fractures, belonging to very low porosity and very low permeability reservoir. The porous rhyolite reservoir is characterized by superposition of commercial gas reservoirs vertically and horizontally, forming large reservoir with high production rate. The rhyolite tuff lava reservoir is blocky gas reservoir with moderate gas production. The rhyolite reservoir has blocky gas reservoir and lower production rate, and can only reach commercial production after fracturing.
2017 Vol. 36 (3): 880-888 [
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521
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995KB] (
751
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889
Depositional environment and organic geochemical characteristics of source rocks of Beipiao Formation in Jinyang Basin
SUN Shou-liang, LI Yong-fei, CHEN Shu-wang, GAO Xiao-yong, SUN Qiu-shi, ZHANG Kun, ZHOU Tie-suo
Based on the core, measured geological profiles, and testing data, the depositional environment and the organic geochemical characteristics of source rocks in the Beipiao Formation of the Jinyang Basin were analyzed. The results show that Beipiao Formation was deposited in freshwater-brackish water environment with partial oxidation,and the climatic changed from humid,semi-humid to semi-dry orderly. The sources rocks are in high abundance of organic matter, which mainly consists of type Ⅱ
2
and some type Ⅲ organic matter. The source rocks are mature and are at the peak of oil generation. Laterally, sources rocks at the Dongkuntouyingzi geological profile and the Shimengou geological profile located in the depositional center of Zhangjiyingzi depression are with high organic matter abundance, and are defined as medium-good source rocks. The source rocks at Diaojiagou geological profile located at the marginal facies of deposition are the worst in terms of organic matter abundance, and are defined as non-poor source rocks. In vertical aspects, the semi-deep lake facies is better than shore-shallow lake facies in terms of organic matter abundance. Braided river delta and fan dalta facies are with non-poor source rocks.
2017 Vol. 36 (3): 889-902 [
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419
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969KB] (
902
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903
Metallogenic characteristics of coal-and oil shale-bearing layers in Meihe Formation of Meihe Basin
ZHANG Kun, LIU Rong, LIU Zhao-jun, ZHANG Chao
Utilizing comprehensive ways of outcrops,core and thin section observation,rock mineral composition, organic geochemistry and industrial analysis,the metallogenic characteristics of the coal and oil shale in the upper coal-bearing strata of the Meihe Formation in the Meihe Basin are deeply analyzed. Research shows that the oil shale has lower volatile and organic carbon content and higher ash content than coal. The oil shale overlying the coal layer has higher organic carbon and volatile content and less ash content than oil shale underlying the coal layer. Generally the organic type of oil shale is type Ⅰ-Ⅱ
2
,of which,for oil shale underlying coal layer,it is typeⅠ,and for oil shale overlying coal layer,it is type Ⅱ
1
-Ⅱ
2
. The organic matter type of coal is type Ⅱ
2
-Ⅲ. As the upper coal bearing strata of the Meihe Formation was developed in the shrinking stage of Meihe Basin,the coal-and oil shale-bearing layers was mainly developed in a fan-delta front-shallow lacustrine-swamp sedimentary environment. Metallogenic sequence of coal and oil shale was mainly formed in the shallow lacustrine environment,which is closely related to the swamp. The main controlling factors on the origin of oil shale and coal depend on the water level in shallow lacustrine stage and ground water table of the swamp stage.
2017 Vol. 36 (3): 903-912 [
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392
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727KB] (
830
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913
Geochemical characteristics and biodegradation of oil in Xiaotaipingshan oil sands
HAO Guo-li, SHAN Xuan-long, TONG Li-hua, LI Feng, LIU Yi-song, WANG Shu-qin, WU Wen-li
Continuous samples of different depths in one layer of Xiaotaipingshan were used for geochemistry and biodegradation analysis. The oil in Xiaotaipingshan oil sands reservoirs generated abundant 25-norhopanes after biodegradation. Conventional hopane and sterane also have been biodegraded. Because of the differences in molecular structure and stability, the biomarkers have different abilities to resist biodegradation. Based on C
21
/C
23
tricyclic terpane, gammacerane/C
30
hopane, Ts/Tm, C
30
rearranged hopane/C
30
hopane, αααC
27
R/αααC
29
R sterane, C
28
αααR/C
29
αααR sterane, C
29
ααα20R/αββ20S sterane, C
29
ααα20R/αββ20R sterane, C
27
diasteranes/(regular steranes+diasteranes) and the ratios of hopane isomers biodegraded to 25-norhopanes, it is indicated that the biodegradation degrees of tar sands oil increase with depths. The degradation degrees of tar sands oil also increase with water saturations, which proves that formation water is beneficial to the migration of bacterial microbes, transmission of nutrients, biodegradation of oil and generation of 25-norhopanes.
2017 Vol. 36 (3): 913-923 [
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445
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774
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924
Simulation of stress field distribution in fractured reservoirs of horizontal wells
ZHOU Xiao-hua, MENG Wen-bo, GAN Di-yuan
Based on the analysis of the influences of hydraulic fracturing on the mechanical parameters of reservoir rocks, a simulation method is proposed to calculate the stress field distribution. By estalishing the in-situ stress field model and hydraulic fracturing induced stress field model of horizontal wells, and using the hydraulic fracturing logging parameters of actual reservoir, the stress field distribution induced by fracturing cracks is calculated. The simulation results show that fracturing induced artificial cracks have a great influence on the reservoir stress field distribution; reservoir stress after fracturing mainly accumulates around the cracks, the farther it is away from the cracks, the less the stress accumulates; the fracture length also affects the distribution of reservoir stress field, the longer the crack is, the slower the crack induced stress field decreases.
2017 Vol. 36 (3): 924-930 [
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295
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522KB] (
1174
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931
Research on joint microseismic monitoring of surface and borehole using amplitude stacking
SUN Hai-lin, QIN Yue-shuang, BAI Tian-zeng, QIAN Peng, XU Ke-bin, LIU Yu-hai, JIANG Hai-yu
The main drawback of microseismic surface monitoring is the lack of vertical positioning resolution, whereas the borehole monitoring is with the problem of low lateral resolution. In this study, the authors improve the reliability of microseismic positioning by means of joint monitoring of surface and borehole, and the noise is suppressed by amplitude stacking method. The feasibility of the method is demonstrated by the inversion experiments of three-dimensional seismic data. The result of source locations from inversion are consistent with the actual source points. In this study, a hydraulic fracturing monitoring in Ningwu Basin of Shanxi is taken as an example, it is proved that the proposed method is feasible in practical application.
2017 Vol. 36 (3): 931-940 [
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277
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1245KB] (
819
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941
Comparative study on precision to extractive solution of surface wave base mode dispersion curve
YAN Ying-wei, WANG Zhe-jiang, HAN Fei
For the problem of the precision of surface wave base mode dispersion curve extracted by different methods, tau-
p
transform, frequency decomposition, frequency-wavenumber transform and high-resolution linear Radon transform are adopted in this study to generate dispersive energy image of synthetic Rayleigh wave seismic record of six-layer incremental geophysical model. The extractive solution of base mode dispersion curve is determined by picking the maximum dispersive energy. The mean square error and correlation coefficient is introduced in order to quantitatively evaluate the proximity between the extractive solution and analytical solution of base mode dispersion curve. The evaluative result shows that the precision of the base mode dispersion curve extracted by high-resolution linear Radon transform is the highest, with mean square error of 11.167 8 and correlation coefficient of 0.994 9. The precision of the base mode dispersion curve extracted by frequency-wavenumber transform is the lowest, with mean square error of 195.274 and correlation coefficient of 0.515 2.
2017 Vol. 36 (3): 941-946 [
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279
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505KB] (
792
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947
New interpretation methods of aeromagnetic gradient data in application of iron mine exploration of Qianan area
JIANG Zhi-qiang, WANG Jian-fei
In order to obtain the distribution feature of geological bodies by the magnetic gradient data clearly and correctly, the authors use total horizontal derivative of analytic signal and gradient Euler deconvolution methods to interpret aeromagnetic gradient data. The maximum of the total horizontal derivative of analytic signal method can define the distribution of the ore bodies, and gradient Euler deconvolution can avoid the interference of background anomaly, and obtain the location and depth of the magnetic source correctly. Theoretical tests show that the combination of total horizontal derivative method and gradient Euler deconvolution method can obtain horizontal range and depth of the magnetic source correctly. The authors apply the presented methods to interpret magnetic gradient data in Qian'an area of Hebei, and delineate five larger iron ore resources in banded distribution, with burial depths of 200 m to 450 m.
2017 Vol. 36 (3): 947-953,963 [
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379
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956KB] (
722
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954
Magnetic susceptibility characteristics of volcanic rock and their influencing factors: a case study of Carboniferous Batamayineishan Formation in eastern Junggar Basin
CHEN Xian, BIAN Wei-hua, WANG Lin-tao, YANG Kai-kai, ZHANG Zeng-bao, LI Zhao
In order to determine the magnetic susceptibility characteristics and to summarize the influencing factors, the authors collected samples of various volcanic rocks and measured them for magnetic susceptibility from the Carboniferous Batamayineishan Formation in the eastern Junggar Basin. The average susceptibilities are 11.705×10
-3
SI, 6.325×10
-3
SI, and 0.345×10
-3
SI for basic, intermediate, and acid volcanic rocks, respectively. The magnetic susceptibility can effectively differentiate the three types of volcanic rocks with different magnetic mineral assemblages. The volcanic rocks in the study area are strongly influenced by diagenesis, and the magnetic susceptibilities are affected by mineral compositions, diagenesis mode, texture and structure,and rock alteration. Further study shows that calcareous, siliceous and other diamagnetic minerals metasomatically replaced the strong magnetic minerals such as pyroxene and hornblende phenocrysts in the rocks at different extent and filled in the apertures as the main interstitial materials, which is the major reason that results in the obviously low susceptibilities of the basic-intermediate volcanic rocks in the study area.
2017 Vol. 36 (3): 954-963 [
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429
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993KB] (
829
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964
Combined application of high density resistivity method and GPR in detecting underground karst caves: a case study of Liuzhou area in Guangxi, China
YU Qing-shui, XU Cong, QI Di, LOU Jun-qing, YUAN Li-jiang, QI Jian-guo, SHAO Feng
In the construction of UHV lines in Liuzhou, Guangxi, the authors used high density resistivity method to detect underground caves, however, it is difficult to determine whether the high resistivity anomaly is the response of the gas-filled cave or the high resistivity limestone itself. On the basis of high density resistivity method, ground penetrating radar was used to further verify the abnormal fuzzy area. The hyperbolic reflection anomaly in radar result indicated that the high resistivity anomaly is derived from gas-filled cave, rather than the limestone itself.
2017 Vol. 36 (3): 964-969 [
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347
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672KB] (
1066
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970
Research on magnetotelluric signal denoising based on CEEMD and self-adaptive median filtering
WU Zhen-wei, ZENG Zhao-fa, PAN Long-wu
In order to improve the signal-to-noise ratio of the magnetotelluric data, the authors put forward a new denoising method for removing the noises in magnetotelluric data based on the theory of complementary ensemble empirical mode decomposition(CEEMD) and self-adaptive median filtering. By CEEMD decomposing magnetotelluric time-series into different intrinsic mode functions (IMFs) and trend items, and according to the frequency of noise,the authors selectively used self-adaptive median filter to denoise each IMF component to extract useful data from IMFs,then reconstructed the data for signal-noise separation. This method was applied to the measured data, and it is indicated that the method can suppress medium and low frequency noises in magnetotelluric data and inhibit mutation, which improve the signal-to-noise ratio effectively.
2017 Vol. 36 (3): 970-975 [
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265
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546KB] (
693
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976
Application of geo-electro-chemical methods in searching hidden uranium deposits in Jiangshan-Changtai area of Zhejiang
LAN Tian, LUO Xian-rong, CHEN Xiao-qing, YUAN He, YANG Long-kun, WEI Xuan-jian
In order to further understand the effect of using geo-electro-chemical integration technology on finding concealed uranium deposits,to find the prospecting technical indicators of hidden uranium deposits in Changtai-Jiangshan area of Zhejiang,to solve the problems in similar deep prospecting areas, the authors carried out the research on ore prospecting based on geo-electro-chemical extraction method, aided by soil ion conductivity and soil heat-release mercury (Hg).Through the R-type cluster analysis and R-type factor analysis based on the extracting of nine elements such as U, Th, Pb, Zn, Cu, Ag, Mo, V and W by geo-electric method, the results indicate that Th, Pb, Zn, Mo and Ag are most closely related to main ore-forming element U, which can be used as reference index for finding similar concealed uranium deposits. The distribution characteristics of geo-electro-chemical anomalies reveal that the fault structure and contact zone are mainly ore-controlling factors in this area. According to geo-electro-chemical extraction of single element anomalies plane characteristics, abnormal distribution of factor score,synthesize soil ion conductivity,abnormal spatial distribution characteristics of soil heat-release mercury, combined with the geology conditions in study area,the authors delineate seven ore prospective areas in the research area.
2017 Vol. 36 (3): 976-988 [
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206
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731
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989
1-D full frequency apparent resistivity inversion of CSAMT
CHANG Yun, ZHANG Yan-hui, WENG Ai-hua, LI Si-rui, LI Jian-ping, TANG Yu
The authors conducted full frequency apparent resistivity inversion, using frequency from 2
-3
to 2
13
Hz, without near-field and transition area correction but directly using Cagniard apparent resistivity as inverse parameter. The electromagnetic fields of a long wire in horizontal layered media were obtained by using the virtual interface method in the forward modeling, where as the limited memory BFGS method was adopted for inversion. A three-layer model and the measured data were used for inversion and the inversion modeling results matched well with the real data, which validated the application of 1-D full frequency apparent resistivity inversion of CSAM.
2017 Vol. 36 (3): 989-994 [
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393
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456KB] (
668
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995
Experimental study on surface electric field distribution model of borehole-to-surface electrical method
LÜ Shou-hang, DU Li-zhi, YAO Ren, WANG Jie, CHANG Gao-qi
In order to study the electric field distribution of borehole-to-surface method in determining the boundary of the anomalous body, the authors supplied electricity directly through low resistance object (copper plate) which was placed at the fixed position of the water sink in the lab, and monitored the surface electric potential distribution characteristic of the electric field formed by the charged low resistance object. The characteristics of potential distribution in different directions were studied, the potential gradient curve were established by linear fitting. The variation of potential gradient in different directions of anomalous body were also analyzed,and the boundary of the low resistance body was determined. The simulation results show that the potential gradient curve has obvious inflection point on the boundary of the anomalous body. By comparing with the potential distribution, the change of the potential gradient curve at the boundary of the anomalous body can be used as a marker to identify the boundary of the anomalous body.
2017 Vol. 36 (3): 995-1000 [
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195
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439KB] (
633
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1001
Extracting the α-cellulose from Miocene mummified fossil woods of Xianfeng,Yunnan
REN Jun-bo, YANG Si-yu, SU Tao, ZANG Li-bin, QUAN Cheng
This study aimed to verify the availability of fossil cellulose by extracting α-cellulose from the Miocene mummified fossil woods from Xianfeng of Yunnan. In this experiment, five samples in the studied area were first processed by organic solvent separation, alkaline solution separation and inorganic acid separation, and then compared with modern wood α-cellulose and international standard α-cellulose with the help of infrared spectrum detection technique. As a result, it showed that all these three extraction methods could extract α-cellulose from fossil woods, but the individual characteristics were different. Among them, the organic solvent separation experiment process took the longest time, and the alkaline solution separation had the largest sample loss. Whereas the inorganic acid separation method was the most efficientonefor α-celluloseextractionfrommummifiedfossil woods.
2017 Vol. 36 (3): 1001-1007 [
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353
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565KB] (
780
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1008
Simulation analysis of strength of aluminum alloy drilling pipe
ZHOU Hai-long, LIU Bao-chang, WANG Su, LI Chuang
Compared with the traditional steel drilling pipe, aluminum alloy drilling pipe is characterized by small density, high specific strength and no magnetism, so it has a great advantage in drilling operation. The tough underground working environment, such as the collision with the borehole wall, will lead to the deformation of the drilling pipe and reduce its strength. In this paper, Ansys LS-DYNA and Workbench were used to simulate the deformation state of the Φ147 mm aluminum alloy drilling pipe after the collision with the borehole wall, and the strength after the cracks were generated was also analyzed. The results show that when the Φ 147 mm aluminum alloy pipe is being used, the main section of drilling pipe is relatively weak and undergoes plastic deformation when colliding with borehole wall at a speed of 2 m/s, which reduces the performance of the aluminum alloy pipe. When the crack length of the main part of the drilling pipe is greater than 1 mm, the crack propagation will occur under the load, resulting in the fracturing of the drilling pipe. When the main body of the drilling pipe has a crack, under fatigue load, it can only bear one fifth of the load of the non-cracking drilling pipe.
2017 Vol. 36 (3): 1008-1014 [
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180
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575KB] (
670
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1015
Temporal and spatial distribution of extreme precipitation eventsin Qinghai Province in recent 50 years
ZHANG Xin-Yue, SHAO Xiao-Hua, WANG Ming-Chang, WANG Feng-Yan, XU Ze-Shuang
Based on linear inclination estimation, wavelet analysis, Mann-Kendall test and spatial interpolation, the temporal and spatial distribution characteristics of extreme precipitation events in the past 50 years (1962-2013) of 28 meteorological stations with uniform distribution in Qinghai Province were analyzed. The results indicated that the extreme precipitation events in Qinghai Province show an increasing trend in the long-term, and their intensity and frequency variation cycles are 28 and 15 years respectively, however, a few sites show sharp changes in the 1990s. There are obvious variations in the extreme precipitation events over Qinghai Province, which are gradually enhanced from west to east. The frequency of extreme precipitation events in the southern area is higher than that in the northern region, and the extreme precipitation in the southeastern region is the highest. In the past 50 years, the intensity and frequency of extreme precipitation events increased in most areas of Qinghai Province. The increasing trend of extreme precipitation events in the northeastern region is obvious, and only the southeastern end and the northwest end show a decreasing trend, the increasing trend of extreme precipitation events is strengthened from the southeast end and the northwest end to the central part.
2017 Vol. 36 (3): 1015-1023 [
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288
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765
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