Formation of the Late Permian Panzhihua plutonic-hypabyssal-volcanic igneous complex: Implications for the genesis of Fe–Ti oxide deposits and A-type granites of SW China

2010 ◽  
Vol 289 (3-4) ◽  
pp. 509-519 ◽  
Author(s):  
J.G. Shellnutt ◽  
B.-M. Jahn
Keyword(s):  
Late Permian ◽  
Sw China ◽  
Igneous Complex

scholarly journals Origin of a Petrographic Coal Structure and Its Implication for Coalbed Methane Evaluation

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 543
Author(s):  
Wei Cheng ◽  
Ruidong Yang ◽  
Qin Zhang
Keyword(s):  
Coalbed Methane ◽  
Guizhou Province ◽  
Mineral Matter ◽  
Late Permian ◽  
Coal Structure ◽  
Sw China ◽  
Inorganic Matter ◽  
Western Border ◽  
Fractured Coal ◽  
Permian Coal

A petrographic coal structure of Late Permian coals from the Liupanshui coalfield, Western Guizhou, SW China, has been distinguished for its novel macro-lithological characteristics. Petrographic, mineralogical and geochemical studies have been conducted for a typical coal sample (No.3 coal, Songhe coalmine, Panzhou County, China) and its geological genesis and significance for coalbed methane (CBM) evaluation is accordingly discussed. It was found that coal is characterized by a banded structure with intensively fractured vitrain sublayers, where a great number of fractures were developed and filled with massive inorganic matter. The study of coal quality, coal petrography, mineralogy and lanthanides and yttrium (REY) geochemistry of the infilling mineral matter (IMM) indicates that this fractured coal structure resulted from the tissues of coal-forming plants or coal matrix shrinkage, as well as the precipitation of calcium rich groundwater and the addition of terrigenous materials. The coal depositional environment and coal-forming plant are considered to have played a role in inducing the special fractures. This provides a scientific reference for the study of CBM for coal with this fractured structure, such as the Late Permian coal from the western border of Guizhou Province, SW China.

Mineral compositional constraints on petrogenesis and oxide ore genesis of the late Permian Panzhihua layered gabbroic intrusion, SW China

Lithos ◽  
2009 ◽  
Vol 110 (1-4) ◽  
pp. 199-214 ◽  
Author(s):  
Kwan-Nang Pang ◽  
Chusi Li ◽  
Mei-Fu Zhou ◽  
Edward M. Ripley
Keyword(s):  
Late Permian ◽  
Ore Genesis ◽  
Sw China ◽  
Gabbroic Intrusion

Low-δ18O A-type granites in SW China: Evidence for the interaction between the subducted Paleotethyan slab and the Emeishan mantle plume

2021 ◽  
Author(s):  
Jian Xu ◽  
Xiao-Ping Xia ◽  
Qiang Wang ◽  
Christopher J. Spencer ◽  
Bin He ◽  
...  
Keyword(s):  
Oceanic Crust ◽  
Mantle Plume ◽  
Source Region ◽  
Early Triassic ◽  
Late Permian ◽  
Sw China ◽  
Igneous Provinces ◽  
Emeishan Mantle Plume ◽  
Isotope Analyses

The mechanisms and processes by which subducted slab interacted with mantle plume remain controversial, as direct observation of such interaction is difficult to impossible. Compositional heterogeneity of large igneous provinces (LIPs) additionally makes plume-slab interaction hard to detect. Oxygen isotopes are sensitive enough to trace the source of magmas. Here we provide evidence for plume-slab interaction mainly based on in situ zircon Hf-O isotope analyses, as well as whole-rock elemental and Sr-Nd-Hf isotope analyses, on the Late Permian and Early Triassic A-type granites on the margin of the Emeishan LIP in SW China. These granites show typical A-type geochemical characters, such as high total alkali (7.93−9.68 wt%) and field strength element (HFSE, e.g., Zr and Nb) contents, and high FeOT/(FeOT+MgO) (0.87−0.98) and Ga/Al (3.67−5.06) values. The Late Permian (ca. 259 Ma) and Early Triassic (ca. 248 Ma) granites show high Nb/Th (>3.0) and low Y/Nb (<1.2) and Yb/Ta (<2.0) ratios similar to the oceanic island basalts and have near-zero εNd(t) (−0.83 to −0.13 and −0.15 to +0.16, respectively) and depleted εHf(t) (+2.71 to +3.39 and +2.62 to +3.55, respectively). In situ zircon O-Hf analyses yielded anomalously low δ18O (0.2−2.0‰ and 3.2−4.8‰, respectively) and positive εHf(t) (1.6−7.0 and 3.9−8.8, respectively), suggesting varying proportions of hydrothermally altered oceanic crust in their source region. Our results imply that significant amounts of altered Paleotethyan oceanic crust have been subducted in the upper mantle beneath the western South China Block. The nearby rising Emeishan mantle plume may have rapidly entrained and incorporated these oceanic crustal materials to the shallow mantle so that their low-δ18O isotope feature was preserved. Subsequent decompression-related partial melting of this hybrid source formed parental rocks of the low-δ18O A-type granites. Our findings also suggest that LIPs could obtain their compositional (especially oxygen isotope) diversity through the interaction between the subducting slab and rising mantle plume.

scholarly journals Late Permian High-Ti Basalt in Western Guangxi, SW China and Its Link With the Emeishan Large Igneous Province: Geochronological and Geochemical Perspectives

2021 ◽  
Vol 9 ◽  
Author(s):  
Chenguang Zhang ◽  
Renyu Zeng ◽  
Changming Li ◽  
Jian Jiang ◽  
Tianguo Wang ◽  
...  
Keyword(s):  
Weighted Average ◽  
Large Igneous Province ◽  
Late Permian ◽  
Flood Basalts ◽  
Sw China ◽  
Continental Flood Basalts ◽  
Emeishan Large Igneous Province ◽  
Igneous Province ◽  
The Difference ◽  
Emeishan Lip

High-Ti (Ti/Y) flood basalts are widely distributed in the Late Permian Emeishan large igneous province (LIP), SW China, and their spatial distribution and genetic mechanism are important to reveal the role of plume-lithosphere interactions in the LIP origin. Western Guangxi is located on the eastern edge of Emeishan LIP. To explore the genesis of the high-Ti basalt in western Guangxi and any genetic link with the Emeishan LIP, we performed whole-rock geochemical and Sr-Nd isotope and zircon U-Pb-Hf isotope analyses on the Longlin basalts from western Guangxi. The results indicate that the Longlin basalt from Tongdeng area has relatively high SiO2 but low MgO and TFe2O3 contents. The rocks have zircon εHf(t) = −0.42 to 6.41, whole-rock (87Sr/86Sr)i = 0.707167–0.707345, and εNd(t) = −2.5 to −2.14. In contrast, the Longlin basalt from Zhoudong area has relatively low SiO2 but high MgO and TFe2O3 contents. The rocks have whole-rock (87Sr/86Sr)i = 0.706181–0.706191 and εNd(t) = −0.57 to 0.69. Four Longlin basalt samples display LREE enrichments and HREE depletions, and with indistinct δEu and δCe anomalies. LA-ICP-MS zircon U-Pb dating on three Longlin basalt samples (from different localities) yielded consistent weighted average age of 257.9 ± 2.6 Ma (MSWD = 0.55), 259.5 ± 0.75 Ma (MSWD = 3.0), and 256.7 ± 2.0 Ma (MSWD = 0.68), indicating a Late Permian emplacement. Considering the similar age and geochemical features between the Longlin basalt and Emeishan flood basalts, we interpret that the former is spatially, and temporally associated with the Emeishan LIP. Geochemical features show that the high-Ti basalts in western Guangxi resemble Deccan-type continental flood basalts (CFBs), which were derived by decompression melting of the mantle plume. Combined with previous geochemical studies, we suggest that the difference in Ti content and Ti/Y ratio in CFBs are related to the depth and melting degree of mantle source, in which high-Ti features may have been linked to low degree of partial melting in the deep mantle.

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