50 research outputs found
Geochemistry, zircon U-Pb geochronology and Hf isotopes of granites in the Baoshan Block, Western Yunnan: Implications for Early Paleozoic evolution along the Gondwana margin
No full textAbstract not availableMeiling Dong, Guochen Dong, Xuanxue Mo, M. Santosh, Dicheng Zhu, Junchuan Yu, Fei Nie, Zhaochu H
Early Cretaceous continental delamination in the Yangtze Block: evidence from high-Mg adakitic intrusions along the Tanlu fault, central Eastern China
No full textAbstract not availableLiqiong Jia, Xuanxue Mo, M. Santosh, Zhusen Yang, Dan Yang, Guochen Dong, Liang Wang, Xinchun Wang, Xuan W
Tetrahedrite-(Ni), Cu6(Cu4Ni2)Sb4S13, the first nickel member of tetrahedrite group mineral from Luobusa chromite deposits, Tibet, China
No full textTetrahedrite-(Ni) (IMA2021-031), ideally Cu-6(Cu4Ni2)Sb4S13, is the first natural Ni-member of tetrahedrite group mineral found in Luobusa chromite deposit, Tibet, China. The new species occurs as anhedral grains 2 to 20 mu m in size, associated with gersdorffite, vaesite, and chalcostibite, which are disseminated in a matrix of dolomite, magnesite, quartz, Cr-rich mica, and Cr-bearing clinochlore. Tetrahedrite-(Ni) is black in color with a reddish-black streak and metallic luster. It is brittle with uneven fractures and has a calculated density of 5.073 gcm(-3). The mean values of 9 electron micro-probe analyses (wt%) are Cu 39.83, Ni 5.67, Fe 1.45, Sb 21.69, As 5.45, S 25.39, total 99.48, and the empirical formula calculated on the basis of cation = 16 apfu is Cu-M(2)(6.00)M(1)[Cu-4.03(Ni1.55Fe0.42)(Sigma 1.97)](Sigma 6.00)(X(3))(Sb2.85As1.16)(Sigma 4.01)S-12.67. Tetrahedrite-(Ni) is cubic, with space group I43m, a = 10.3478(4) & Aring;, V = 1108.00(14) & Aring;(3), and Z = 2. Its crystal structure has been solved by X-ray single-crystal diffraction on the basis of 188 independent reflections, with a final R-1 = 0.0327. Tetrahedrite-(Ni) is isostructural with tetrahedrite group minerals. It represents the first natural tetrahedrite-group mineral with a Ni-dominated charge-compensating constituent. Tetrahedrite-(Ni) may be the product of late-serpentinization at moderately high-temperature conditions around 350 degrees C. In this case, tetrahedrite-(Ni) and its mineral paragenesis record an entire geological process of nickel enrichment, migration, activation, precipitation, and alteration from deep mantle to shallow crust
Nomenclature of the ancylite supergroup
No full textThe ancylite supergroup is approved by the IMA-CNMNC, with the general crystal chemical formula (M3+xM2+2-x)(CO3)2[(OH)x·(2–x)H2O] (1 ≤ x ≤ 2, Z = 2). The ancylite supergroup can be divided into two groups defined by different proportions of the M cation and hydroxyl anion and/or water molecule: the ancylite group is defined for 1 ≤ x ≤ 1.5; the kozoite group is defined for 1.5 < x ≤ 2. The ancylite supergroup minerals are orthorhombic with space group Pmcn, or monoclinic with space group Pm11, and have a crystal structure with species-defining trivalent and divalent M cations (M = La3+, Ce3+, Nd3+, Ca2+, Sr2+ and Pb2+) which centre ten-vertex polyhedron formed by oxygen atoms at three independent O sites. At the vertices of triangular (CO3)2- anion, two are oxygen atoms, while the third one, O(3), is statistically filled with (OH)- groups and H2O molecules. The triangular faces of three oxygen atoms of MO10 coordination polyhedra join the chains of this ten-vertex polyhedral, which is extended along the c axis. (CO3) triangles connect chains in three dimensions. Up to now, eight valid mineral species with M2+ = Sr2+, Ca2+ and Pb2+ belong to the ancylite group [ancylite-(La), ancylite-(Ce), calcioancylite-(La), calcioancylite-(Ce), calcioancylite-(Nd), gysinite-(La), gysinite-(Ce), and gysinite-(Nd)]. Two hydroxyl carbonates with only rare earth elements as species-defining cations, kozoite-(La) and kozoite-(Nd) are members of the kozoite group
Triassic ore-bearing and barren porphyries in the Zhongdian Arc of SW China: implications for the subduction of the Palaeo-Tethys Ocean
No full textThe NS-treading Zhongdian Arc located in the southern part of the Yidun Arc is an important region to address the evolution and reconstruction of the Palaeo-Tethys Ocean and related mineralization. In this study, we investigate three barren intrusions in the Zhongdian Arc and present geochemical compositions, zircon U–Pb dating and Hf isotopic compositions. Zircons from the three intrusions yielded U–Pb ages of ~227.5, ~222.5, and ~230 Ma, with highly variable εHf(t) values (‒20.5 to 4.3). These quartz monzonite porphyries show typical adakitic affinity, and it is inferred that these intrusions in the Zhongdian Arc, together with those in the northern Yidun Arc, were derived from the partial melting of mantle wedge and contaminated by minor lower crustal components during the westward subduction of the Ganzi-litang Ocean, which probably resulted from the Triassic continental collision between the south China and the north China blocks. In the Yidun Arc, the Triassic ore-bearing intrusions have εHf(t) values that cluster around zero, while the barren intrusions possess negative εHf(t) values, suggesting that the mantle lithospheric components played an important role in the Triassic ore-bearing porphyries.Peng Wang, Guochen Dong, M. Santosh, Xuefeng Li and Meiling Don
Supplemental Material: Multiple sources and magmatic evolution of the Late Triassic Daocheng batholith in the Yidun Terrane: Implications for evolution of the Paleo-Tethys Ocean in the eastern Tibetan Plateau
No full textTable S1: Mineral association of samples from the Daocheng batholith; Table S2: LA-ICP-MS U-Pb isotopic data for zircons from the Daocheng batholith; Table S3: Hf isotopic data for zircons from the Daocheng batholith; Table S4: Trace elements data for zircons from the Daocheng batholith; Table S5: Major and trace elements data for the Daocheng batholith; Table S6: Whole-rock Sr-Nd isotopic data of the Daocheng batholith; Table S7: Representative microprobe analyses of amphibole from the Daocheng batholith; Table S8: Partition coefficient for minerals used in geochemical modeling
Emplacement and evolution of zoned plutons: Multiproxy isotopic and geochemical evidence from the peraluminous Laojunshan leucogranite suite, southwestern China, and implications on the regional geodynamic and metallogenic history
No full textThe petrogenesis and geodynamic setting of peraluminous leucogranites are important topics for reconstructing regional geodynamic and metallogenic models. Here we present the results of an integrated study of zircon U-Pb ages and Hf-O isotopic compositions, monazite U-Th-Pb-Nd isotopes, tourmaline boron isotope, and bulk-rock elemental and Sr-Nd isotope geochemistry of an unusual suite of leucogranite, the Laojunshan leucogranite (LJSL), from the southwestern margin of the Yangtze Block in southwest China. The LJSL samples are strongly peraluminous with their zircon d18O (8.8–10.2 ‰) and tourmaline d11B ( 14.32 to 12.75 ‰) values suggesting S-type origin. The LJSL rocks show high SiO2, Al2O3, K2O and Rb/Sr, low P2O5, CaO, FeOt , MgO, low REE abundances with moderate LREE enrichment and strong negative Eu anomalies, high (87Sr/86Sr)i (0.7127–0.7421) and low eNd(t) ( 10.36 to 12.67). These features suggest protracted fractional crystallization from S-type parental granitoid magmas with Ti-in-zircon thermometry giving a mean temperature of 760 C. The bulk-rock Sr-Nd, monazite Nd and zircon HfO isotope data suggest that the S-type magmas parental to the LJSL formed through partial melting involving muscovite-breakdown in the Paleoproterozoic middle-upper crustal metasedimentary rocks. Zircon and monazite U-(Th)-Pb dating reveals three intrusive phases for the LJSL (91–89 Ma, 87– 85 Ma and 83–82 Ma), correlating with the compression-to-extension tectonic regime transition in response to the subduction polarity change from northwestward subduction of the Okhotomorsk block to northward subduction of the Neotethys oceanic lithosphere. Our findings contribute to the understanding of Mesozoic plate reconstruction associated with the India-Asia collision in the Cenozoic.Yanbin Liu, Lifei Zhang, M. Santosh, Guochen Dong, Chaoyang Que, Chengxue Yan
Triassic ore-bearing and barren porphyries in the Zhongdian Arc of SW China: implications for the subduction of the Palaeo-Tethys Ocean
No full textRecent Progress of Toxic Gas Sensors Based on 3D Graphene Frameworks
No full textAir pollution is becoming an increasingly important global issue. Toxic gases such as ammonia, nitrogen dioxide, and volatile organic compounds (VOCs) like phenol are very common air pollutants. To date, various sensing methods have been proposed to detect these toxic gases. Researchers are trying their best to build sensors with the lowest detection limit, the highest sensitivity, and the best selectivity. As a 2D material, graphene is very sensitive to many gases and so can be used for gas sensors. Recent studies have shown that graphene with a 3D structure can increase the gas sensitivity of the sensors. The limit of detection (LOD) of the sensors can be upgraded from ppm level to several ppb level. In this review, the recent progress of the gas sensors based on 3D graphene frameworks in the detection of harmful gases is summarized and discussed
Multistage Evolution of Oceanic Upper Mantle: Evidence from Lesveos Ophiolitic Peridotites, Greece
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