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In order to enhance the understanding of Archean continental crust formation and evolution history of Liaonan block in North China Craton, the Neoarchean TTG(tonalite-trondhjemite-granodiorite)gneisses in Shijianfang area of Liaonan block were focused on, and the detailed field investigation, zircon U-Pb dating and Lu-Hf isotope analysis, and whole-rock geochemical analysis were intergrated. The results show that TTG gneiss in Shijianfang area crystallizes at(2 499.7±5.4)Ma. The TTG gneiss samples have high contents of SiO2(66.1%-69.1%)and Al2O3(14.6%-15.6%), are enriched in Na and depleted in K(K2O/Na2O is 0.41-0.51)with weakly positive Eu anomalies(1.06-1.59); the samples are relatively enriched in large ion lithophile elements(Ba, Rb, K, etc.)and high field strength elements(Zr, Hf, etc.), featured by high Sr/Y(44.3-69.5)and(La/Yb)N(11.8-24.0), and depleted zircon Hf isotopic composition with two-stage model ages of 2 903-2 687 Ma. Compared with TTG rocks derived from partial melting of the thickened lower crust, TTG gneisses in Shijianfang area have relatively higher contents of MgO, Cr and Ni. The above geochemical characteristics reveal TTG gneisses in Shijianfang area are typical medium-pressure TTG rocks, which is the product of partial melting of Meso-Neoarchean basaltic crust. The source area is rich in garnet and amphibolite, but short of rutile and plagioclase. Combined with previous studies, TTG gneisses in Shijianfang area are likely formed by the partial melting of subduction slabs, indicating the warm subduction tectonic system of the ancient continental margin. The North China Craton might be controlled by both plate tectonics and mantle plume tectonics during Late Neoarchean. [ABSTRACT FROM AUTHOR]

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Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Lower Devonian Lianhuashan Formation is unconformly unlained by Cambrian strata due to Early Paleozoic Yunan orogeny and Kwangsian orogeny in Dayaoshan area of Guangxi. The new petrology and whole-rock geochemical data of Lower Devonian Lianhuashan Formation in Dayaoshan area were presented in order to constrain their provenance and sedimentary tectonic setting. The sandstones are composed of the predominated moderately sorted and rounded quartz and sedimentary lithic fragments, indicating a close detrital provenance. These samples have obviously high SiO2 contents ( 7 4. 19 % - 95. 35 % with an average of 85. 72%), low Al2 O3 contents 0. 23%-14. 73% with an average of 6. 48%), TiO2 contents (0. 09% -1. 05% with an average of 0. 38%) and Al2 O3 /SiO2 (0. 01- 0. 20). The sandstones have low REE contents ( (12. 48- 281. 10) X 10- 6 ) and are characterized by depletion in LILE, enrichments in HFSE and LREE ((La/ Yb)N is 3. 70- 29. 40) coupled with slightly negnative Eu anomaly (0. 66-1. 14 with an average of 0. 88). The high SiO2 /AlzO3 (5. 04-77. 28 with an average of 22. 30) implies the high grade of maturity. The wide ranges of ICV (0. 61- 2. 13 with an average of 1. 21) and high CIA ( 82. 13 - 91. 68) indicate that the source rocks contain recycled ancient sediments and first-cycle materials, which have experienced high degree of chemical weathering and alteration in the heat and humid climate environment of tropical or subtropical zone. Integrated with geochemistry, elastic zircon U-Pb geochronology, paleogeography and tectonic evolution, it is suggested that Lower Devonian Lianhuashan Formation is deposited in passive margin, and its provenance may be Dayaoshan-Damingshan area in the north, and Yunkai area in the south. The source rocks of Lower Devonian Lianhuashan Formation mainly comprise Cambrian Huangdongkou Formation, and minor Neoproterozoic sedimentary rocks of Cathaysia block and the granitoids formed in Kwangsian orogeny (470-435 Ma). [ABSTRACT FROM AUTHOR]

Earlier Cambrian banded iron construction (BIF) type iron ore is the most important source of iron in China, accounting for more than 60% of the country's iron reserves, of which the BiF type iron ore in the late Neo-Archean period in North China is the most typical. Detailed petrology, geochemistry and isotopic studies were carried out on the Bif and surrounding rocks of the Xiaolai River in the Qingyuan region of Liaoning Province, northeast of Craton, North China, aiming to provide constraints on the source area and tectonic environment. Xiaolaihe BIF is mainly composed of magnetite, quartz and silicates (such as iron perilla pyroxene, etc.), and the SiO and all-iron (FeO) content of the samples varies widely. The AlO content (mass fraction, the same below) in a small number of Xiaolai River BIF samples was higher (>1%), indicating the presence of an input of land-based clastic material during the sedimentation process. The BIF samples, which were not contaminated with clastic substances, showed typical seawater characteristics, including low alO, high field strength elements and transition metal elements, relative loss of light rare earth elements, and enrichment of heavy rare earth elements and Eu positive anomalies. The simulation results showed that the sample matched the PAAS standardized rare earth element dispensing pattern of the seabed high temperature hydrothermal and seawater 1:100 mixed solution, indicating that the hydrothermal activity on the seabed provided heat and substances to the BIF. The mineralization of the Bif of the Xiaolai River comes from the base-super-bedrock rock at the bottom of the Qingyuan greenstone belt leached with high temperature hydrothermal fluid. The surrounding rocks of the Xiaolai River BIF are mainly metamorphic volcanic rocks of the Stone Shed Subgroup and a small amount of metamorphic clastic sedimentary rocks. The geochemical characteristics of clastic sedimentary rocks are controlled by the composition of complex source regions with medium-low degree of weathering under the island arc system (such as Aochang granite, Yingyun diorite and a small amount of bedrock), which is similar to the source area of the Xiaolai River BIF. Based on the geological, geochemical, isotopic, chronological and other characteristics of the deposit, it is believed that the Xiaolai River BIF system was formed in the Post-Arc Basin of the Algoma-type BIF [ABSTRACT FROM AUTHOR]

The discriminant indexes, petrogenesis and tectonic significance of unfractionated A-type granites have been widely recognized, while there has not been a universal consensus on the discriminant criterion of highly fractionated A-type granites. LA-ICP-MS zircon U-Pb dating shows that Dajin granites form at Early Paleozoic(～440 Ma), and have high Rb contents(>400×10-6), Rb/Sr and Rb/Ba values, and relatively low Zr/Hf values, illustrating that they are highly fractionated. According to the high zircon saturation temperature(819 ℃-863 ℃), and high Ga/Al(2.6-3.1), Zr+Nb+Ce+Y contents and the evolution trend of specific geochemical indexes, Dajin granites are comprehensively determined as highly fractionated A-type granites. Combining with geochemical and Nd-Hf isotopic compositions, it is suggested that Dajin granites are mostly likely generated by partial melting of the mafic lower crustal rocks, and experienced high degree fractional crystallization and contamination of a samall amount of the wall rock materials. As consequence to post-orogenic lithospheric delamination, the forming time of Dajin A-type granites represent the timing of geodynamic transition of Kwangsian orogeny from orogenic compression to post-orogenic extension in the northeastern Guangxi. [ABSTRACT FROM AUTHOR]

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Gejiu area in Yunnan is located at a faulted depression basin in the southwestern of Youjiang continental margin rift basin, which is the transitional zone between Yangtze platform and South China Caledonian geosyncline, and the tectonic location is in the southwestern South China. The geology, geochemistry of Late Ladinian-Norian meta-basalt in Tabai area of Gejiu, Yunnan indicate that these basalts have undergone strong metamorphism because of regional dynamic tectonics. The meta-basalts are characterized by low contents of silica, calcium, magnesium, and enrichment of incompatible elements(Ti, P, K, etc.). They can be classified as high-Ti alkaline basalts. The trace elements are characterized by extremely low contents of Rb and Ba, severely depletion in Sr and enrichment in Ta, Ti, Zr, Hf, Th, which is similar to the weak crustal contamination of the Emeishan high-Ti basalt. The chondrite-normalized REE pattern shows LREE enrichment and weak positive Eu anomaly. The Sr-Nd isotopes suggest that meta-basalts in Tabai area of Gejiu are mainly from the primitive mantle and fall in the oceanic island basalts(OIB), which are of the same origin as Emeishan high-Ti basalts. Emeishan mantle plume activity has ended in Late Permian. Therefore, the stretching of Yangtze massif in Triassic and the subduction of Simao massif to Yangtze massif induce Emeishan mantle plume stigma to a low degree of partial melting. Because the influence of mantle plume activity lasts for a long time, the energy of mantle plume activity is low in some areas, the basaltic magma does not erupt to the surface and forms magma chamber. Meta-basalts in Tabai area of Gejiu are formed in the relatively weak stage of the center of mantle plume magma activity, especially in the edge zone of mantle plume activity center, the relatively thick lithosphere, and low melting degree. The magma chamber activity in Late Triassic re-erupts and forms basalt. [ABSTRACT FROM AUTHOR]

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The eastern Yangtze Gorges area in Hubei belongs to the Upper Yangtze block of South China plate. The cherts from Ordovician Nanjinguan Formation limestone in this area are mostly developed as nodules and strips. Based on the detailed field geological survey, the petrography and geochemistry characteristics of these cherts were analysed, and the genesis and sedimentary environment were discussed. The results show that the main mineral compositions of cherts are quartz and chalcedony. C herts are poor in Mn and Fe. the ratios of Al/C A1 + Fe+Mn) range from 0. 27 to 0. 84 with an average of 0. 64. which is closer to that of the biogenic cherts. The ratio of Mno/ Tio2 is much less than 0. 5. indicating cherts in this area form in the shallow sea sedimentary environment near the edge of the land. The ratios of l h IJ range from 0. 02 to 0. 86 with an average of 0. 24. C herts have low REE content, the total REE content is (0. 67-27. 79)X 10-6. l he NASC'-normalized REE pattern shows a relatively gentle right-leaning trend. the 8('e ranges from 0. 97 to 1. 19 with an average of 1.11. and the average value of (La/Yb)N is 1. 31 . reflecting a bio-chemical origin rather than hydrothermal origin, and cherts form in a selling of continental margin. The carbon and oxygen isotope information of the host limestone of cherts in Nanjinguan Formation shows that the o1 ( ranges from -2. 37%r, to 2. 30%r. with an average of - 0.006 4%o. the 818 O ranges from -9. 04%o to - 6. 49%c with an average of -7.61 %c. The paleoenvironmental temperature varies from 4 C to 21 C. l he geochemistry characteristics of cherts in Nanjinguan Formation limestone indicate that cherts are biogenic origin and form in a warm and anoxic continental marginal tectonic sellings. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Since great breakthrough was made in purifying lithium carbonate from brine with high content of magnesium and low content of lithium, extracting lithium from brine has obtained increasing attention in China. Potassium-rich brine in the northeastern Sichuan contains many kinds of rare metals such as lithium which is urgently demanded in strategic emerging industries, while associated lithium resources of potassium-bearing brine are rarely considered in previous studies. A borehole(ZK001)with the depth of 3 227 m was arranged in deep exploration project in Xuanhan area of the northeastern Sichuan, of which the main goal is to investigate lithium-bearing brines in the deep. Analysis of fluids during drilling(conventional circulating drilling gas)is a main method of conventional real-time monitoring of wellhead fluids. As a result of lithium’s active property, it is difficult to reveal enrichment features of lithium by gas component only. Fluids of borehole ZK001(include deep brine, fluids during drilling, drilling-washing water), surface water and groundwater around borehole ZK001 were collected and analyzed; the characteristics of fluids during drilling were obtained for the first time; and the vertical variations of lithium and other components of drilling fluids in borehole ZK001 were summarized. The lithium concentrations in different types of water around borehole ZK001 show a rule that deep brine, drilling-washing water, fluids during drilling, groundwater, and surface water in descending order. By comparing the profile characteristics of the composition of fluids during drilling in borehole ZK001, it is discovered that lithium concentration of fluids during drilling in the depth of 0-500 m is relatively high while the ratio of Mg/Li is low. It is revealed that lithium concentration of fluids during drilling is proportional to the depth, and the ratio of Mg/Li is inversely proportional to depth. Lithium concentration of yellow brine collected at the depth of 3 000 m from borehole ZK001 is 10 556 μg·L-1(the ratio of Mg/Li is 33.92), which almost reaches the half of the cut-off grade(24 599 μg·L-1). In addition, Na, K, Rb, Sr components of the yellow brine from borehole ZK001 reach industrial grade. These features of fluids from borehole ZK001 will provide scientific support for future arrangement in drilling engineering. [ABSTRACT FROM AUTHOR]