Table of Content

11 October 2023, Volume 29 Issue 5

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Genesis Process of the Cretaceous Daqushan Pluton in Zhejiang Province: Crystal-Melt Separation and Magmatic Recharge

HE Chen, XIA Yan, XU Xisheng, QIU Jiansheng, XU Hang, ZHANG Zhi, ZHAO Sidi

2023, 29(5):  657-678.  DOI: 10.16108/j.issn1006-7493.2022018

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The models of trans-crustal magmatic system and crystal mush provide new insights into the study of Cretaceous magmatism in northeast China. The Daqushan pluton is located in the northeast of coastal Zhejiang and Fujian. It is mainly composed of K-feldspar granite with abundant melanocratic microgranular enclaves (MME) and is locally traversed by several mafic-intermediate dikes. A small outcrop of monzonite is exposed near the Chaotoumen. MME have a fine-grained texture with acicular apatites. Zircon U-Pb dating results show that the rock samples in the Daqushan pluton (including the K-feldspar granite, MME, monzonite, and mafic-intermediate dikes) crystallized at ~100 Ma. The K-feldspar granite are highly silicic (SiO2=68.45%-73.82%). While the miarolitic granite (DQS-7) without MME has the higher silica (76.27%), and its whole-rock geochemical and Sr-Nd isotope compositions are similar to those of coeval high silica granites (SiO2>75%) exposed around the Daqushan pluton. Daqushan K-feldspar granite bearing aggregates of plagioclase and K-feldspar exhibit“complementary”trace element geochemical characteristics with Daqushan miarolite and surrounding high silica granites. Further researches show that the Daqushan K-feldspar granite and miarolite were formed by felsic magma which originated from the partial melting of the ancient crustal basement and was recharged by mantle-derived magma. Such felsic magma underwent fractional crystallization and the extraction of high silica melt. Then, the residual silicic cumulate of the crystal mush and high silica melt crystallized and formed the Daqushan K-feldspar granite, miarolite and the surrounding coeval high silica granites. The mafic dikes of Daqushan are enriched in LILEs and depleted in HFSEs
and are derived from the partial melting of the enriched mantle metasomatized by subducted dehydration fluids. The results of EPMA analyses indicate that the plagioclase in the K-feldspar granite and MME has a core-mantle-rim texture with low- An in the core (27-36, 25-41) and rim (17-32, 18-26) and relatively high-An in the mantle (28-57, 27-65). Integration of the element geochemical characteristics and Sr-Nd-Hf isotopic results, monzonite and intermediate dikes should be the product of magma mixing of mantle-derived mafic magma and felsic magma, while MME are the product of magma mingling of the two endmembers. The results of the Al-in-hornblende geobarometer show that the crystallization depth of MME is 1.8- 3.0 km, hornblende in monzonite develops core-mantle-rim texture, the crystallization depth of hornblende core and mantle is 17.0-21.2 km, and the depth of hornblende rim is 1.9-4.5 km. Based on the study of the origin and genetic relationships of K-feldspar granite, MME, miarolite, monzonite and mafic-intermediate dikes, and compared with the surrounding coeval high silica granites, this study establishes a model of trans-crustal magmatic systems for Daqushan pluton. The rollback of the subducting paleo-Pacific plate, the back-arc extension in the coastal area and the upwelling of the asthenosphere led to the underplating of the mantle-derived mafic magma, and further induced the partial melting of basement rocks in the lower crust to produce felsic magma. The continuous recharge and heating of mantle-derived magma favor the existence of long-lived melt-bearing regions in magma chambers, promoting magma differentiation and crystal-melt separation and thus forming two magma chambers with depths of 17-21 km and 2-3 km, respectively. K-feldspar granite, high silica granites, monzonite, MME and intermediate-mafic dikes were formed by magma mingling/mixing and crystal-melt separation in two connected magma chambers at different depths.


Sr-Nd-Pb Isotopic Composition of the Chinese National Standard Igneous Rock Powders Measured by the Thermal Ionization Mass Spectrometry

WANG Zhiyi, CHENG Hong, ZHAO Jingxin, YE Risheng, LI Weiyong, HE Jianfeng, CHEN Fukun

2023, 29(5):  679-692.  DOI: 10.16108/j.issn1006-7493.2022017

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In this study, Sr-Nd-Pb isotopic compositions of three Chinese national igneous rock standard materials, GSR-1 granite, GSR-2 andesite, and GSR-3 basalt, were measured by means of the techniques of the isotopic dilution and the thermal ionization mass spectrometry, to investigate the homogeneity of their isotopic compositions and the suitability for the usage as rock standard materials. Three international rock standard materials, BCR-2 basalt, BHVO-2 basalt, and AGV-2 andesite, produced by the US Geological Survey, were simultaneously analyzed as reference materials to check the reliability of the analytical procedures. The analytical results show that three national standard materials of igneous rocks have homogeneous Sr and Nd isotopic compositions. Compared to the GSR-1 granite, the GSR-2 andesite and GSR-3 basalt yield homogeneous Pb isotopic compositions. Relatively large variation in Pb isotopic composition of the GSR-1 granite might be caused by the addition of radiogenic Pb isotopes from those minerals having high U and Th contents. On the basis of the analytical results reported in this study, it is suggested that the three national standard materials of igneous rock powders are suitable as the reference materials for the Sr and Nd isotopic measurements and, the GSR-2 andesite and GSR-3 basalt are also the ideal candidates as reference materials f or the Pb isotopic analysis.

Trace Element Characteristics and Geological Significance of Sphalerite in Xiwan Lead-Zinc Deposit, Luzong Basin, Anhui Province

ZHANG Hongqiu, HAN Shanchu, ZHANG Yong, PAN Jiayong, ZHANG Yanqun, ZHAO Bibo, DING Yong, JIANG Yao, HU Shengping

2023, 29(5):  693-704.  DOI: 10.16108/j.issn1006-7493.2022028

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The Luzong volcanic basin is an important part of the metallogenic belt in the middle and lower reaches of the Yangtze River. In recent years, a large-scale Xiwan lead-zinc deposit has been discovered in the East Ma’anshan Formation on its northern margin. Previous studies have shown that sphalerite in this deposit is enriched in certain dispersed elements, but there are few in-depth studies on its content and distribution characteristics and comprehensive evaluation of dispersed elements is lacking. Therefore, in this paper, the LA-ICP-MS analytical method was used to study the characteristics of trace elements in sphalerite of No. Ⅳ and Ⅴ ore bodies in the Xiwan lead-zinc deposit and discuss its geological significance. The results show that (1) Sphalerite is rich in Fe, Mn, Cd, Pb elements, and depleted in In, Tl, Se, Te, Sn elements, among which dispersed Cd element has certain comprehensive utilization values; (2) The substitution mechanisms of trace elements in sphalerite mainly include single element and multi-element coupling. Among them, the substitution mechanism of single element mainly includes Fe²⁺ instead of Zn²⁺, Cd²⁺ instead of Zn²⁺, etc. The multi-element coupling substitution mechanism mainly includes (Cu⁺+Ge³⁺) instead of 2Zn²⁺, (2Cu⁺+Ge⁴⁺) instead of 3Zn²⁺, etc.; (3) The composition characteristics of Fe, Mn, Cd, In and other trace elements (dispersed elements) in sphalerite show that the metallogenic temperature of the Xiwan lead -zinc deposit is medium to low temperatures, which belong to the epithermal deposit. 

Mechanisms of Ce(III) Oxidation and Fixation by Coexisting Iron and Manganese Oxides

ZHAO Hanyue, ZHOU Yuefei, LI Xiaosong, XIE Qiaoqin, CHEN Tianhu

2023, 29(5):  705-712.  DOI: 10.16108/j.issn1006-7493.2022031

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In this study, we conducted bulk and dynamic experiments to investigate the efficiency of Ce (III) oxidation and fixation by Mn-contained limonite and goethite. Based on experimental results, the mechanism of Ce oxidation and fixation by coexisting iron and manganese, and its geological significance, are discussed. Results of bulk experiments show that Mn-contained limonite has a high performance on the oxidation and fixation of Ce; Ce was totally removed after 48 hours under solution with Ce concentration of 6000 μg/L and limonite concentration of 1 g/L. For experiments with initial Ce concentrations of 300 to 4500 μg/L, Ce removal is positively correlated with Mn content for limonite experiments. As for goethite, it decreased Ce removal when comparing to the control experiments. Results of dynamic adsorption experiments show that for high-Mn limonite, the distribution of Ce is constrained not by Mn minerals, but by iron oxides. The results of this study indicates that: (1) the process of Ce oxidation and precipitation is adsorption of Ce (III) -oxidation of Ce(III) to Ce(IV)-precipitation of Ce(IV) minerals-autocatalytic oxidation of Ce(III) to Ce(IV) by CeO₂, and (2) the contributions of coexisted Mn and Fe oxides to Ce oxidation and fixation are Mn oxides promoting the oxidation of Ce(III) and Fe oxides promoting the precipitation of CeO₂ through electrostatic attraction. This study is significant in explaining the geological phenomenon that although Mn oxides have higher Ce(III) oxidation ability than that of Fe oxides, under Fe- and Mn-oxides coexisting conditions, Ce tends to be fixed by Fe oxides.

Grain-size Characteristics and Environmental Implication of Neogene Red Clays in the Chinese Loess Plateau

LU Keke, CHEN Zhong, YANG Yanpeng, ZHANG Jialin, ZHAO Zhongqiang, XIA Dinghong, NI Chunzhong, SONG Yinxian, ZHANG Shitao

2023, 29(5):  713-725.  DOI: 10.16108/j.issn1006-7493.2022020

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The aeolian origin of red clays in the Loess Plateau has been unanimously recognized. The earliest red clay was found in the late Oligocene and early Miocene, indicating that the arid environment had been formed in the inland northwest of China at the end of Paleogene. The grain size characteristics of red clay in the loess plateau show that the average grain size gradually decreases from the north to the south, indicatin g that the initial monsoon system has been established, and the winter wind played an important role in the transport of aeolian dust. The grain size distribution of red clay indiactes that it is composed of two components. The coarse grain (>20 μm) represents those transported by the near surface wind (winter wind), while the fine grain (<5 μm) represents those transported by the upper westerly wind. The grain size composition characteristics of red clays well record the development and change of atmospheric circulation. Since the end of Oligocene, the average grain size and sedimentation rate of red clays in the west of Liupanshan Mountain increased at 21.3-20.2 Ma, 16.0-13.3 Ma and 8.7-6.9 Ma, which may be related to global cooling and the Qinghai-Tibet Plateau uplift, and the 8.7- 6.9 Ma increase was mainly controlled by global cooling. In the red clay section to the east of Liupanshan, the grain size of variation characteristics shows that the grains deposited during 7.6 Ma to 6.2 Ma or to 5.4 Ma is coarse, indicating that the winter monsoon was strong. After that, the average particle size was fine up to 3.6 Ma, and the deposition rate was low, indicating that the winter monsoon was weak climate environment. From 3.6 Ma to 2.6 Ma, most profiles show an increase in mean grain size, an increase in sedimentation rates, and an increase in both winter and summer monsoon, which indicates to the transition to Quaternary glacial period. The development of the Arctic ice sheet and the uplift of the Qinghai-Tibet Plateau may have contributed to these changes.

Structural Characteristics and Deformation Mechanisms of Multipledetachments in Luzhou area, Southeastern Sichuan Basin

ZHAO Shengxian, XU Wenqiao, YANG Xuefeng, YIN Hongwei, LI Bo, WANG Wei, ZHANG Chenglin, JIA Dong, LIU Yongyang, XIE Wei, ZHANG Dongjun, LI Changsheng

2023, 29(5):  726-734.  DOI: 10.16108/j.issn1006-7493.2022029

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In recent years, shale gas exploration and development in southeastern Sichuan has gradually expanded to the deep areas. The Luzhou area shows great potential of shale gas exploration and development with the depth over 3500 m. In order to further clarify the characteristics and evolution mechanism of various structural deformation in Luzhou area, the main controlling factors of fold belt were explored by using discrete element numerical simulation based on structural analysis of seismic data, and the evolution process of Mesozoic and Cenozoic was restored. And the following research results show that multiple detachment layers and regional tectonic compression are the main controlling factors of structural deformation in Luzhou area. Influenced by multiple detachment layers, Luzhou area has developed low steep thin-skinned structure and obvious vertical stratification, forming complex structure such as fault-propagation folds, detachment folds, buried folds and duplex structures between detachment layers. Among them, the lower Cambrian gypsum rock plays a major role in controlling the deformation, and the gypsum rock and shale slippage coordinate and accumulate towards the core of the anticlines. Since the late Yanshanian, the multi-detachment allochthonous succession with regional compression in Luzhou area were developed the thin-skinned comb-shaped folds. The fold belt rose again in Himalayan, the displacement of the original fault sand shear zones increased, and a series of secondary faults and buried folds formed between the detachment layers. The reservoirs are easy to be destroyed at anticline zones, while the syncline areas are a favorable area for shale gas exploration. The relatively simple deformation for syncline composed of ramp thrusts results in comparable stable internal stress distribution.

Influence of Subducting Plate Viscosity to Double-slab Subduction with Inward-dipping Directions: Numerical Modeling

LI Zhongyuan, WU Benjun

2023, 29(5):  735-742.  DOI: 10.16108/j.issn1006-7493.2022010

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Plate subduction is an important part of plate tectonic theory. Although there have been many numerical simulations of single-slab subduction, the mechanism of multi-plate interactions is still unclear and needs further study. In this paper, a two-dimensional geodynamic numerical model is established to study the dynamics of double-slab subduction with inward dipping and to explore the influence of subducting plate viscosity on the coupling interaction of multiple plates. The simulation results show that the difference in viscosity of the left and right subducting plates leads to the difference in the subduction velocity of the plates. The subducting plate with small viscosity sinks faster, enters the lower mantle first, folds periodically and stacks in the lower mantle. The subducting plate with high viscosity enters the lower mantle afterwards. It is obstructed by the mantle circulation with slab tip rollover and slips backward in the lower mantle. The difference in subduction speed and morphology between the left and right slabs also causes the overlying slab to move toward the side of the less viscous subducting plate, causing this side of the trench to retreat and the other side to advance. The results of this paper provide a dynamical explanation for the evolution of the complex tectonics in the Southeast Asian region. The India-Australia plate and the Pacific plate in the Southeast Asia region subducted in opposite directions, and the two plates interacted with each other to form a complex convergent subduction system, which caused the mantle upwelling and probably the origin of the Cenozoic magmatic rocks in the S outh China Sea region.

Discrete Element Numerical Simulation of the Sspin Evolution Process of Rubble Pile Asteroids

ZHANG Chenwei, LIU Chun, GENG Huan, LIU Hui

2023, 29(5):  743-755.  DOI: 10.16108/j.issn1006-7493.2022022

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In recent years, exploration research has shown that the rubble pile structure formed by gravity and cohesion may be an important method of asteroid formation. To explore the evolution mechanism of this kind of asteroid, this paper makes secondary developments based on the discrete element software MatDEM and realizes the calculation of the element’s gravitational force. A numerical model of a “rubble mound” asteroid with a diameter of 1.2 km is established, and the rotational remodelling and failure processes of spherical aggregates under different adhesion strength and bulk densities are analysed by numerical simulation. The results show that spherical aggregates are affected by the initial increment of angular velocity to start the remodelling process of aggregates, leading to deformation or failure. With the decrease in the adhesion strength, the model will be destroyed more easily. Before destruction, the asteroid will maintain the stability of its configuration by deforming into an oblate ellipsoid. The increase in bulk density effectively increases the structural stability of the asteroid model with a certain adhesion strength, can delay the occurrence of asteroid destruction, and the number of particles falling off decreases with the increase of density. Discrete element analysis can better simulate the spin evolution process of asteroids. Combined with real asteroid data, it is beneficial to explore the mechanism of asteroid spin evolution and destruction deeply and comprehensively. 

Study on Optical Fiber Temperature Measurements and Ground Temperature Changes in Pumping and Irrigation Wells of Carbonate Thermal Storage

SHI Qipeng, TAN Xianfeng, MENG Jia, ZHENG Huiming, ZHANG Xi, LIU Xiao, SONG Shuailiang, DU Ying

2023, 29(5):  756-765.  DOI: 10.16108/j.issn1006-7493.2022013

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Carbonate thermal reservoirs have the characteristics of rich geothermal resources, good mining conditions and large water inflow of single wells, and represent one type of the main thermal reservoirs for the development and utilization of middle and deep geothermal resources. In the process of long-term geothermal exploitation and tail water reinjection, it is necessary to maintain the hydraulic connection between pumping and irrigation wells to avoid thermal breakthrough, The long-term monitoring of thermal reservoir temperature, analysis, and calculation of heat sources in pumping and irrigation wells are important topics for sustainable development and utilization of geothermal resources. This paper introduces the distributed optical fiber temperature measurement technology of pumping and irrigation wells, monitors the influence of pumping and reinjection of carbonate thermal storage on ground temperature, and analyzes the heat sources and quantity of heat storage temperature recovery using the monitoring data. The results show that (1) the heat storage temperature of the pumping well decreased significantly on the sixth day after heating with an average decrease of 1.6 ℃、 which was affected by the small spacing of pumping and irrigation wells and the dominant channel of carbonate heat reservoir, and the pumping and irrigation well produced a thermal breakthrough； the heat storage temperature of the reinjection well failed to recover to the initial temperature before the second heating season due to a large amount of low-temperature tail water reinjection for a long time, and the temperature of pumping well basically recovered. Analysis reveals that the main source of reservoir heat recovery is geothermal water convection and heat accumulation, followed by high-temperature reservoir and geothermal water conduction and heat accumulation. The results of this study show that under the condition of large-scale reinjection, the temperature of reinjection well decreases and the thermal breakthrough of pumping and irrigation well is an inevitable development trend. In order to promote the sustainable development and utilization of geothermal resources, it is very necessary to study the appropriate well spacing of pumping and irrigation wells to prevent thermal breakthrough in a short timescale.

Provenance and Sedimentary Facies of the Member 3 of Paleogene Dongying Formation in the Eastern Part of the Liaohe Depression Tidal Area

XIA Changfa, LIN Chunming, ZHANG Xia, HUANG Shuya, LI Xulong, ZHAO Xuepei, LI Xin, SONG Fulai, ZOU Bingfang, LI Tiejun

2023, 29(5):  766-775.  DOI: 10.16108/j.issn1006-7493.2022030

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The Member 3 of Paleogene Dongying Formation (E₂d₃) in the eastern part of the Liaohe Depression tidal area is a key target layer for oil and gas exploration. Based on the data of core and logging, the provenance and sedimentary facies of E₂d₃ in the study area were analyzed by combining clastic components, heavy minerals, sedimentary elements, and core facies with logging. The analysis results show that there are three provenance systems of the E₂d₃ in the tidal area, namely northern provenance, eastern provenance, and Yuedong buried hill in the northwest; the sedimentary facies in the study area are mainly composed of the braided river delta frontal subfacies and shore-shallow lacustrine subfacies, which are controlled by the tectonic background and provenance, and the sedimentary distribution of the three subsections in the E₂d₃ of the study area is relatively similar, the braided river delta front is mainly developed in the northern part of the study area, while the braided river delta front and shore-shallow lacustrine beach-bar are developed in the eastern area, and shoreshallow lacustrine beach-bar is developed in the northwest area. Our study provides a sedimentary geological basis for the further exploration and favorable reservoir prediction of the E₂d₃ in the east of the Liaohe depression tidal area. 

Sedimentary Characteristics of the Triassic Karamay Formation in the North Hongshanzui Area, Junggar Basin

WANG Jin, YU Xinghe, LU Fenghao, NIU Xiaojun, YE Zhaorui, YANG xintao

2023, 29(5):  776-787.  DOI: 10.16108/j.issn1006-7493.2022024

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The obvious sedimentary differences can be found between the upper and lower parts of the Karamay Formation in the north of Hongshanzui. To determine the sedimentary characteristics of the Karamay Formation, the seismic, core logging, and analytical data were used to analyze the rock and mineral characteristics, typical lithofacies, and sedimentary facies of the Karamay Formation. The results show that the lower Karamay Formation is characterized by the braided river deposits with obvious traction-current deposition, which is mainly composed of braided channel (Gi → St → Sp → (Sh) → Md), braided bar (St→Sp↔Sm), and alluvial plain (Mr↔Md → Fr). The channel sand-bodies are banded and mostly isolated from thick mudstone. The upper Karamay Formation is dominated by fan-delta with debris flow, density flow and tractioncurrent deposits. The braided channel (Gmm→Gcm→Gi→Sh), braided distributary channel (Gcm→Gi↔Gt) and braided bar (Gp↔Gi→Gcm) are developed in the fan-delta plain. The underwater distributary channel (Gi→Gt→Gp→St), mouth bar (Md→Sp↔Sw) and interdistributary bay (Md↔Sc) are developed in the fan-delta front. The thick stacked sandy conglomerate bodies are scours and overlap with each other and also characterized by good connectivity and broad distribution. The transformation from the braided river to fan-delta in the Karamay Formation is mainly controlled by the forwarded provenance system and increased supply capacity, the transition of the paleoclimate from arid and semi-arid to sub-humid and humid, and the lake level rise. 

Overview of New Taxa on Global Vertebrate Fossil during 2017-2021

WANG Haohan, ZHU Min, SHI Xiaodong, PAN Zhaohui

2023, 29(5):  788-794.  DOI: 10.16108/j.issn1006-7493.2022026

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Biodiversity data of vertebrate fossils is important information source for studying earth history and life evolution. The species list of vertebrate fossils is an essential basis for studying the diversity of global vertebrate fossils. Reviewing new taxa and literature on vertebrate fossils can reveal the research hotspots of vertebrate fossils diversity and grasp disciplinary development directions on a time scale. Based on the DeepBone Database, this study reviews the annual variation characteristics of taxa and literature, distribution countries of the holotype, published journals, and significant contributing institutions of new taxa on the different categories of global vertebrate fossils during 2017-2021 using bibliometrics analysis. The result shows that 2662 new taxa emerged, and 1946 literature were published on global vertebrate fossils during 2017-2021. New taxa and literature on vertebrate fossils have decreased since the outbreak of COVID-19 at the end of 2019. Countries with a high distribution of the holotype of new taxa for global vertebrate fossils during 2017-2021 and are rich in vertebrate fossil resources, are strong in the economic and scientific research, mainly including the United States, China, New Zealand, Argentina, and Germany. Journal of Vertebrate Paleontology, Cretaceous Research, Historical Biology, PeerJ, and Journal of Systematic Palaeontology are the prominent journals

on new taxa of vertebrate fossils. The institutions with a high contribution to the new taxa for vertebrate fossils are the Chinese Acad Sci, Russian Acad Sci, Consejo Nacl Invest Cient & Tecn, Nat Hist Museum, and the research cooperations of various institutions are very close. The study of taxonomy on vertebrate fossils in China has reached a high level in the world. We should continue to strengthen the accumulation of primary data on vertebrate fossils diversity to provide the DeepBone database for exploring the origin and evolution of bio diversity in the future.