Volcanic reservoirs are critical deep hydrocarbon exploration targets, but the complex relationship between chlorite occurrence types and reservoir quality in mafic volcanic successions remains poorly constrained. This study investigates Emeishan basalts from Well A (southwestern Sichuan Basin) using integrated geochemical, mineralogical, and petrophysical methods. Four chlorite occurrence types are identified, with distinct Fe/(Fe+Mg) compositional variations. A three-stage alteration sequence is delineated, and a ~3 m thick tight barrier layer formed by dense matrix replacement and pervasive amygdale-filling chlorite vertically compartmentalizes the reservoir. Chlorite exerts context-dependent effects: matrix replacement and pseudomorphic chlorite generally are preferentially associated with intervals exhibiting higher porosity; fracture-filling and amygdale-filling chlorite commonly occur in intervals characterized by reduced porosity and permeability. This study proposes an occurrence-based framework for interpreting reservoir heterogeneity in mafic volcanic rocks, providing practical reference for volcanic reservoir evaluation.

Southwestern Guizhou is an important area of concentrated Carlin-type gold deposits in China, and ore with unseen gold is an important feature. However, recent research has discovered that the geological and geochemical characteristics of gold deposits are different from those of traditional Carlin-type gold deposits in the United States, which has led to long-term uncertainties about the genetic type and mineralization mode of gold deposits in this area. In this study, through in situ microanalysis, such as high-precision electron probe microanalyzer (EPMA) and environmental scanning electron microscopy (ESEM)), the gold in the ore was identified as occurring in both unseen nanogold and particulate gold. U/Pb dating of gold-bearing hydrothermal dolomite (Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)) and in situ rare earth element tests show that hydrothermal dolomitization occurred in the middle Yanshanian period at 177.36±4.88 Ma, and chondrite-normalized rare earth elements have low LaN/SmN values (0.04~0.23) and high GdN/YbN values (2.7~16.57). The partition model shows the “convex” characteristics of light and heavy rare earth depletion and medium rare earth enrichment. Characteristic values of positive Eu anomalies and negative Ce anomalies differ from those of the early stage microdisseminated gold deposits. It is revealed that the ore-forming hydrothermal fluids of native particulate gold have the genetic characteristics of shell origin and high oxygen fugacity. This type of mineralization characteristic of the superposition of at least two stages of mineralization in southwestern Guizhou may be an important limiting condition for large-superlarge gold deposits, such as Shuiyindong.

The Yeba Formation volcanic rocks preserve important information of the early Neo-Tethys subduction. Here, we report the discovery of these volcanic rocks at Epingsong (southeast of the Yeba Formation), which fill the gap of the Yeba Formation at Sangri. Timing of volcanism in the eastern and western Yeba Formation is discussed. Systemic studies on petrology, whole-rock geochemistry, zircon U-Pb age, whole-rock Sr-Nd isotopes and in situ zircon Lu-Hf isotopes reveals that the rocks are calc-alkaline andesitic to felsic, and were emplaced in the Early Jurassic (ca. 191.4–174.0 Ma). The andesitic rocks have medium Mg# value (28.3–50.2, avg. 40.1), low Cr (4.68–36.01 ppm) and Ni (3.63–12.70 ppm) contents. They have slightly positive Eu/Eu* anomalies (1.0–1.13), and display continental arc affinity, as featured by enrichments in light rare earth elements (LREEs) and large ion lithophile elements (LILEs; e.g. Rb, K, Ba), but depletions in high-field strength elements (HFSE; e.g. Nb, Ta, Ti and Hf). The Yeba andesite has largely positive whole-rock εNd (+3.6) and zircon εHf (−1.3 to +10.9) values. The felsic rocks have low Mg# values (19.2–42.3), MREE depletion (e.g. Tb, Dy and Ho), and negative Eu/Eu* anomalies (0.76–0.96). They have varying εNd (0.9–2.9) and εHf (2.1–10.4) values, with two-stage model ages (tDM2) of 560–1098 Ma. The results indicate that the andesitic-felsic rocks were probably sourced from partial melting of the lower crust by mantle-derived magma underplating, and mixed with subducted sediment-derived melts (2.0–7.5%) and assimilated ancient crystalline basement. The Yeba volcanic rocks likely record an important tectonic transition from subduction compression to extension.

Super-deep drilling in the central Sichuan Basin encountered volcanic rocks of the Suxiong Formation, which are overlain by multiple hydrothermal alterations within the upper section of the Ediacaran Dengying Formation. This provides an excellent research opportunity to understand the pre-Cambrian hydrothermal activity and geological evolution of the western margin of the Yangtze Craton. Observations revealed the development of a series of hydrothermal dolomite aggregates characterized by the presence of brown sphalerite within fractures and pores of the carbonate rock. Microscopically, the dolomite exhibited fibrous columnar crystallization, forming radial bands with a gradual decrease in crystallization intensity from the center to the periphery. Cathodoluminescence analysis revealed the presence of approximately eight dolomite bands within the aggregate. U–Pb dating from the inner to outer bands yielded isotopic ages of 781 ± 12 Ma for the second band, 683 ± 12 Ma for the fifth, 562 ± 12 Ma for the sixth, and 545.4 ± 6.9 Ma for the seventh. The in situ rare earth element (REE) distribution patterns of the 781 and 683 Ma dolomite bands exhibited similarities. They both showed low total REE content (∑REE), with significant fractionation between light and heavy REEs. Additionally, they exhibited negative anomalies in cerium (Ce) and europium (Eu), while heavy REEs were relatively enriched. The dolomite bands at 562 and 545 Ma also exhibited similar REE characteristics, with low ∑REE and weak fractionation between light and heavy REEs. They also displayed distinct negative anomalies in Ce and Eu, indicating similar distribution patterns. These findings suggested that formation of the banded hydrothermal dolostone occurred during different tectonic events, and the presence of heavy REE-enriched hydrothermal fluids suggested a deep-seated origin. This study has provided preliminary evidence that the Dengying Formation, previously considered to be of the Ediacaran age, has undergone multiple episodes of deep-seated fluid infiltration and alteration since the Mesoproterozoic Era. Importantly, these events coincide with the rifting of the Rodinia and Pannotia supercontinents, aligning with their respective timeframes. This finding raises questions regarding the stratigraphic division and correlation of the formations in the deeply buried core area of the basin.

In this paper, we describe gravity flow facies that form the base of the Meiji Reef system in the South China Sea, and discuss their palaeoclimate significance. These Early Oligocene (26.1-23.5 Myr) deposits occur in Well NK1 and comprise a 110.6 m thick succession developed on top of volcanic basement. The deposits can be divided into two intervals, both of which are dominated by debris flow facies. The lower 17.6 m thick interval has a gravel content of 50-65% with parent rocks including dacite, basalt, tuff, and coral reef fragments. From base to top, these units coarsen upward and show increasing gravel contents. Gravel clasts are well-rounded but poorly sorted (diameter 10-350 mm), which, together with their complex composition, indicate transportation by the gravity flows from the near-shore volcanic rock basement to the slope. The upper 93 m thick interval comprises abundant bioclastic materials, including benthic foraminifera, crustal red algae, and red algae detritus, with a few volcanic gravel clasts. The content of volcanic rock gravels decreases towards the top, which may be attributed to the reduction or disappearance of volcanic rocks in the provenance area due to the establishment of coral reef facies that cap the succession and dominate the overlying interval from a core depth of 885.6 m to the seafloor. Based on U-Pb dating, the cap-shaped red algae laminae at the facies transition were formed at 24.6 +/- 1.1 Ma, dating the earliest initiation of reef building to end-Oligocene times. The emergence of gravity flow sediments during the early Oligocene may be attributed to the onset of the Antarctic glaciation and concurrent regional tectonic activities that led to a shallowing of the sea. The origin of debris with high roundness char-acteristics is believed to be associated with transportation along the slope triggered by tectonic and climatic events, resulting in the formation of debris flow deposits. Studying the gravity flow facies at the Meiji Reef system is crucial for determining the onset of reef-building and helps establish the relationship between gravity flow deposition, paleoclimate, and regional tectonic evolution in the South China Sea.

In the western Mangling orefield, the molybdenum (Mo) polymetallic deposits are closely related to the ore-bearing porphyry stocks (individual outcrop size: <1 km 2 ). In this study, we have discovered several granitic stocks at Yaozhuang. Systematic petrologic, zircon U-Pb-Hf isotope and whole-rock geochemical studies show that both the granitic stocks of porphyritic granite (157 ± 2 Ma) and the intruding monzogranite dike (153 ± 1 Ma) were emplaced in the Late Jurassic. These granitic stocks are characterized by high SiO 2 (66.83–75.63 wt%), high K 2 O (4.15–5.05 wt%), high Al 2 O 3 (12.90–16.93 wt%), and low MgO (0.06–0.73 wt%) and are metaluminous to weakly peraluminous, being highly fractionated I-A-type transition granites. The content of the total rare Earth element (ΣREE) of the porphyritic granite (139.6–161.7 ppm) is lower than that of the monzogranite (151.4–253.6 ppm). The porphyritic granite has weakly negative Eu anomalies (Eu/Eu* = 0.77–0.93), whereas the monzogranite has weakly positive Eu anomalies (Eu/Eu* = 0.97–1.21) and are more enriched in light rare Earth elements. Both of them are enriched in large ion lithophile elements (LILEs, e.g., K, Rb, and Ba) but depleted in high-field-strength elements (HFSEs, e.g., Nb, Ta, Ti, Zr, and Hf). The zircon ε Hf (t) values of all the samples range from −16.1 to −6.9, and the two-stage model ages (t DM2 ) are 1.78–2.16 Ga. The magma may have originated from partial melting of the lower crust (more than 40 km in depth) caused by mantle-derived magma underwelling. The plutons and stocks were emplaced into the intersection of the early EW-trending faults and the late (Yanshanian) NE-trending faults. The fertile magma with high water content (H 2 O > 4%) and high oxygen fugacity (Delta FMQ > 1.5) indicates that the Yaozhuang area has significant potential for porphyry Mo polymetallic ore discovery.

The Sichuan Basin, located on the western side of the Yangtze Craton, is a nearly rhomboid tectonic-sedimentary basin affected by large NE- and NW-trending faults. The characteristics of the basin were controlled mainly by the evolution of the Tethys tectonic domain. Volcanic rocks formed by the eruption of a large amount of basaltic magma over a short period of time were influenced by the activities of the mantle plume at Mount Emei during the Late Permian. These rocks are the main targets for exploration of the volcanic rock reservoir in the basin. When studying the volcanic rock reservoir in the Sichuan Basin and surrounding areas, the author discovered that the Emeishan basalts in typical sections included several lithologic assemblages, such as pyroxene basalt, trachyte basalt, and oblique porphyry basalt, all of which were affected by chloritization, silicification, carbonation, fluorite mineralization, and other hydrothermal alterations. In addition, the intensity of alteration and the distribution of amygdules showed a spatial coupling relationship of strong alteration and densely distributed amygdules near the fault and weaker alteration and sparsely distributed amygdules in locations away from the fault. Microscopic examination revealed that the hydrothermal minerals chlorite, calcite, and quartz found in the amygdules could have been filled multiple times and that the minerals showed gradual increase in crystallinity from the edge to center. The amygdules had a bead-like distribution along microcracks, indicating that this type of amygdules may not have been formed from normal hydrothermal crystallization of pores after the magmatic period. To explore the genesis of different forms of amygdules in the basalts of Mount Emei, a detailed analysis of the typical alteration minerals was carried out in combination with in situ rare earth element (REE) and U-Pb isotopic tests of the minerals. U-Pb isotopic dating showed that the calcite in different parts of the amygdules had four isotopic ages: 236.9 +/- 19.6, 184.2 +/- 13.2, 125.90 +/- 6.43, and 114.06 +/- 3.76 Ma. The in situ REEs of the alteration minerals showed that the cryptocrystalline chlorite altered from the matrix mafic minerals had partition characteristics similar to those of the Emeishan basalt. The total REEs of chlorites in amygdules decreased gradually from the edge to the center, showing the characteristics of a deep hydrothermal source mixed with formation water. The granular quartz in the cores of the amygdules showed a flat partition pattern with weak negative Ce and Eu anomalies, which was consistent with the regional hydrothermal fluid. The characteristics of the phosphate deposits were similar; the coarse-grained calcite in the cores of the amygdules is often associated with fluorite, apatite, and others, and the REEs showed a strong left-dipping feature of positive Ce anomaly, suggesting that the alteration fluid may have come from the deep mantle source. The results of this study preliminarily determined that the different U-Pb alteration ages of calcite are the constraints and responses of the Emeishan basalts to thermal events in the western margin of the Yangtze Plate. At the least, the Emeishan basalt experienced fluid superposition and transformation at different tectonic stages in the Late Indosinian, Early Yanshan, and Late Yanshan periods following its eruption at the end of the Paleozoic. The basalt reservoir at Mount Emei is mainly composed of secondary amygdules residual pores and secondary dissolution micropores caused by micro-scale structure-induced hydrothermal erosion. Regional tectonic-magmatic events acted on the basalt of Mount Emei, causing the basalt to undergo a series of transformations of structural fragmentation, hydrothermal dissolution, and alteration filling, which might have been the basic prerequisite for the formation of high-quality volcanic rock reservoir in the basin.

"晶体光学"课程具有很强的理论性、抽象性和空间性特点,需要在显微镜下反复操作及实践才能掌握.在有限的学时内,既保证课程理论教学的深度和广度,强化显微镜下鉴定的实践能力,又培养学生的综合分析能力与创新精神,课程团队对该课程按照"金课"的标准进行一系列的建设、改革、创新与实践.精选优质教学素材,精心凝练教学内容,建设了优质的视频资源库和兼具基础性与高阶性的习题库,启发学生的创新思维和创新能力;引入"慕课堂"等智慧教学工具,构建了多种先进教学方法相结合的线上线下混合式教学模式,建立了线上单元知识点测验、线下显微

The Ediacaran Period represents a critical transition in the Earth's evolution, which could be potentially revealed by analyzing the oncolites formed during this period. This study investigates the genesis of oncolites in the Ediacaran Dengying Formation in the Yangba profile, Nanjiang County, Sichuan Basin. Moreover, efforts are made to analyze the effects of terrigenous input from perspectives of rare earth elements, probe into the variation of redox conditions via the microscopic analysis of trace elements, and exemplify the coupling relationship between the oxygen isotope, strontium isotope, paleosalinity (indicated by Z values), and sea level variation. The oncolites in the Yangba profile are generally featured by thin skins and dispersal grains and are highly differ-entiated in size and shape. A large number of microbial laminated fabrics and framboidal pyrite are developed in the dark laminae, and the former is yellow-green under the fluorescence microscope. According to the 13C -enrichment and petrographic analyses, oncolites and organic matter should be autochthonously formed by geochemical processes linked to microbial mats. Three cycles of sedimentary microfacies formed in subtidal low-energy zone and subtidal high-energy zone, and ten upward-coarsening cycles of oncolites are identified vertically, which, together with the vertical variations of delta 18O and 87Sr/86Sr, indicate that the sea level has expe-rienced six stages of variations during the deposition of the 2nd Member of the Ediacaran Dengying Formation (Deng-II Member): namely, transgression, lowstand fluctuating regression, transgression, continuous regression, transgression, and again lowstand fluctuating regression. Negative Ce anomalies (Ce/Ce*) and low V/Cr and low V/(V + Ni) ratios indicate the presence of molecular O2 in the water column, whereas characteristic Ni/Co, U/Th, and framboidal pyrite suggest the contemporaneous presence of anoxic water. The oncolites are suggested to be rarely impacted by terrigenous input, as is evident by the Er/Nd ratio of < 0.1, the average Y/Ho ratio of 35, the average La/Yb ratio of 36, and the Z value of > 130. To conclude, Upper Yangtze Deng-II Member oncolites are exemplified to be of microbial origins; the marine redox structure is featured by a temporarily stratified, oxygen-ated water body and a less oxygenated deeper water body during the Ediacaran, and frequent change of seawater energy, which are consistent with the Ediacaran seawater properties.(c) 2022 Elsevier B.V. All rights reserved.

Abstract Aim at the problems that the genesis and deep dynamic mechanism of Paleozoic-Mesozoic granites in the north western margin of South Altun Mountains have not been analyzed on the whole, systematic petrographic and elemental geochemistry studies on granites in the eastern segment of South Altun Mountains were carried out. The lithology of the area is mainly granite, granodiorite and monzonite, with SiO2 of 57.35% ~ 88.11%, Al2O3 of 3.84%~19.56%, and total alkali content 1.00%~9.92%, with different degrees of Eu (Eu is 0.24~1.04), which belongs to the alkalic-alkali calcic-calc alkalic-calcic series, all of which have the characteristics of peraluminous, enrichment of large ion lithophile elements(LILE) and loss of high field strength elements(HFSE). Based on the results of previous studies and the classification of Sr-Yb, the Palaeo-mesozoic magmatism in this area can be divided into six episode: episode 1 (484-458 Ma) is the Nanling Mountains I-type granite, which may be derived from partial melts of metamorphic basalts; episode 2 (450~406 Ma) is Himalayan and Zhejiang mixed type granites, which have I-S and S type granites respectively, and the source areas are partial melts products of garnet amphibolite and metamorphic mudstone sandstone respectively; episode 3 (404~385 Ma) is the Nanling Mountains A2-type granite, which may be the partial melts product of the granodiorite at low pressure ; episode 4 (380~343 Ma) is the post-collisional uplifts of the Adakite and Zhejiang type granites, which are of type I granite and are related to the crustal detachment;and episode 5 (253~280 Ma) is the Nanling Mountains S type granites, It may be derived from the partial melts of metamorphic mudstone, which is the product of the closure of the Tethys Ocean; episode 6(154 ~ 230 Ma) is Himalayan I-type granite, and the source area is the partial melts product of meta-sandstone, which is related to subduction of residual ocean basin.

利用钻井、测井等资料,通过对火山岩薄片鉴定,结合野外剖面露头及区域地质研究成果,对川东地区二叠系储层特征进行研究.结果表明,火山岩主要分布在龙潭组中部和底部,岩相主要为火山溢流相和火山沉积相,储集空间类型主要为原生气孔、溶蚀孔及各类裂缝.溶蚀改造是影响储层的关键因素,沉凝灰岩类中形成的溶蚀孔缝和脱玻化孔是主要的储集空间,火山熔岩受喷发方式和构造作用影响形成的气孔和裂缝,是储层形成的重要因素;构造作用对储层储集性能具有建设性作用,构造形成的裂缝不仅自身可作为良好的储集空间,也改善了储渗关系.

The micro-disseminated gold mineralization in Southwest Guizhou is a typical medium-low temperature hydrothermal deposit,which is generally controlled by different levels of structures. However,the lens and lamellar orebodies,characterized by the strata-bounded nature of Au mineralization,are quite different from the spatial distribution of most hydrothermal deposits,whose genetic mechanism is not clearly understood. The morphology,composition and distribution of pyrite and the occurrence of Au in the Shuiyindong gold deposit have been analyzed through EPMA,ESEM and other high-precision in-situ test methods. The results indicated that there are at least three types of pyrites,which are all closely associated with organic matter. (1)The coarse pyrite:It is densely disseminated or banded in the calcareous sandstone of the Member I of the Longtan Formation. Condensate and hydrothermal minerals such as apatite,rutile and calcite are often found in the pores of coarse pyrite. Some coarse pyrite has a regular core with 2 similar to 3 outer layers of secondary enlarged rings containing As,which are the major gold-bearing minerals. Invisible Au mainly exists in the outer ring,and the content of Au is 0. 06% on average and up to 0. 24%. The elements such as S,As and Au show an annular distribution, indicating that the inner and outer zones were formed in different metallogenic stages. (2) The fine pyrite:It is distributed in a scattered or sparse fashion in the calcareous tuff,rich in bioclasts in the Member. of the Longtan Formation,and constitutes the economic orebodies. It is mostly symbiotic with arsenopyrite,and rich in Au and As,with Au constituting up to 0. 14%. The organic matter contains natural gold particles with sizes of 5 similar to 10 mu m and is found in the microcracks of the surrounding rock. (3) The framboidal pyrite:It is distributed in the Member I and II of the Longtan Formation in the microfossils (Ty1)and microfractures (Ty2) as aggregates. Ty1 has a metasomatic bioclastic formation and organic matter cladding,whereas Ty2 is found in microfractures rich in organic matter,and metasomatizes some coarse and fine crystals of pyrite,indicating that it is formed slightly later than the main metallogenic stage. The above research on the structure,composition,and spatial occurrence of pyrite in the Shuiyindong deposits indicates that this type of gold deposit has the characteristics of multiple overprinting of hydrothermal activities. Under the metasomatism of an ore-forming hydrothermal solution,numerous bioclasts in the Longtan Formation and its underlying strata were decomposed into organic matter and other elements such as C,P,N,Ca,Na,K,etc. The ore. forming fluid carries organic matter upward and the dense Member. of the Longtan Formation and its upper strata provide lithofacies traps for the Au mineralization like a cap. During the mineralization process,the organic matter which formed by fluid metasomatized bioclasts may help to reduce the solubility of Au,promoting its precipitation and enrichment,and forming the orebodies with fracture.controlled and strata-bounded characteristics.

The Yeba volcanic rocks preserve important information of the early Neo-Tethys subduction, which is coeval with the Xiongcun Cu ore-formation in the southern Lhasa terrane.We report the Epingsong volcanic rocks of the southernmost Yeba Formation. of the volcanic rocks were emplaced at ca. 191.4-174.0Ma.All samples obviously have an affinity of the continental margin island-arc, and are rich in LREEs and LILEs but depleted in HFSE.The Yeba andesite is calc-alkaline, medium Mg # (28.3-50.2),and have low Cr (4.68-36.01ppm) and Ni (3.63-12.70ppm), and Eu/Eu* values (1.0-1.13), as well as positive ε Nd value (+3.6) and ε Hf values (-1.3-+10.9).The results indicate that they were probably sourced from the interaction between subducted sediment-derived melts (2-7.5%) and the depleted mantle wedge.The melt was originated from the partial melting of Grt + Sp lherzolite dominated by Sp.The felsic rocks have low Mg # values (19.2-42.3),and MREE depletion (e.g., Tb, Dy and Ho), and Eu/Eu* (0.76-0.96), as well as variable ε Nd values (0.9-2.9) and ε Hf values (2.1-10.4),with two-stage model ages (t DM2 ) of 560-1098 Ma.This implies that the magma is sourced from partial melting of amphibole-rich juvenile crust, accompanied by ancient crystalline basement contamination and crustal assimilation.The Yeba volcanic rocks exhibit slightly bimodal characteristics, and likely record an important tectonic transition from Neo-Tethyan subduction compression to transient extension.Slab-rollback triggers this deep dynamic process.

在工程教育专业认证和双一流学科建设背景下,传统地学实验教学面临革新."沉积岩与沉积相"课内实验教学以逆向设计(BD)和成果导向(OBE)为指导,从支撑毕业的指标点出发重新设置教学计划,引入线上+线下"混合式教学,组织学生进行小组讨论,丰富教学活动的方式和手段,激发学生学习兴趣、锻炼学生解决复杂沉积岩问题的能力.建立一套师生互动评价体系,对课程进行动态跟踪和持续改进.

We present detailed geochronological,geochemical and Sm-Nd isotopic data for the host biotite monzogranite with mafic microgranular enclaves (MMEs)in the Tumuertai of the central Inner Mongolia, northern North China Craton (NCC). LA-ICP-MS U- Pb zircon ages from host biotite monzogranite yielded ages ranging from 273Ma to 271Ma, and 268 +/- 2Ma for the MMEs. The biotite monzogranite exhibit uniform LREE-enriched patterns, and enrichment in K, Rb, Th and LREEs, but depletion in Nb, P, Ti and HREEs, with features of I-type granite, showing typical geochemical signatures of continental arc rocks. epsilon(Hf)(t)isotope from the biotite monzogranite range from - 13. 0 to - 6. 1, with t(DM2) model ages of 2. 12 similar to 1. 68Ga. The results are coupled with the Nd isotope, varying from - 11. 3 to - 10. 7, with tDM ages from 2. 44Ga to 1. 73Ga. Similar results were observed in the MMEs, i. e., the epsilon(Nd)(t) values range from - 11. 1 to - 10. 2, with tDM ages from 2. 13Ga to 1. 85Ga. Content of apatite and associated mafic minerals in the MMEs are higher than those in the host biotite monzogranite. These arc-related magmatic rocks were likely derived from crust. mantle interaction induced by deep subduction of the Paleo-Asian Ocean, following the partial melting of lower crust. We favor that the Paleo-Asian Oceanic plate has not vanished completely in the northern NCC, at least in part, until in the Early-Middle Permian.

Based on field geological surveys of two deep-water sedimentary outcrops in the Yanchang formation of the Ordos Basin, X-ray diffraction analysis, elemental geochemical analysis, and polarizing microscope observations were conducted to investigate the causes of various sedimentary structures inside the massive sand bodies from deep-water debris flow. A genesis model of deep-water debris-flow sandstone is established: during the handling of the mass transport complexes in the basin slope, the soft sandy sedimentary layer with relatively strong shear resistance tears the soft muddy sedimentary layer with weak shear resistance and pulls various clumps inside the muddy layer. Finally, debris-flow massive sandstones with rich sedimentary structures are formed. Through argon ion polishing and field emission scanning electron microscopy, the debris-flow sandstones mainly develop micron-scale pores, and the pore radius is mainly distributed in the range of 1-8 mu m. The sedimentary rocks from the semi-deep lake to deep lake facies only have a small number of nano-scale pores, and the pore radius is distributed between 20 and 120 nm.

在地质类专业基础课中进行引导式教学模式的探索与实践,是适应当代大学生自主学习能力培养的重要方式,也是新工科背景下培养创新型人才的有益尝试.讨论引导式教学模式在地质类专业基础课教学中的构建原则,并举例展现具体的教学设计,结合实际教学效果提出建议.

The Mesozoic lake basin in the Ordos Basin has a stable Craton basement, and the sedimentary bottom is flat. Most of the areas are delta-Huxiang sedimentary strata. However, in the middle part of the lake basin, the upper 7 upper strata can be seen to be truncated. The distribution of the Chang 6 stratum is obviously controlled by the slope break zone, and the reflection inside is characterized by lenticular or wedge shape. Through the later exploration practice, hundreds of millions of tons of petroleum resources were found in the Chang 6 stratum of the lake facies in the Huaqing area in the middle of the lake basin. The reservoir is a gravity flow composite sand body controlled by a slope break zone. Therefore, identifying the cause of this type of slope break zone and the plane distribution position of the slope break zone in this area are very important for the subsequent exploration direction and development capacity deployment. On the basis of a large amount of physical workload, the authors use the combination of well and earthquake data to determine the sedimentary paleo environment. The Chang 6-stage sedimentary slope is located in the line of Yuan 281Bai136-Bail 63-Bai230-Bai265, and the upper part of the slope is the northern Shaanxi delta. The southward extension of the group is favorable for sedimentary microfacies as the delta front subaqueous distributary channel and estuary dam deposit. The deep water gravity flow developed in the south is deposited as multiple sandy debris flow tongues. It is pointed out that the favorable exploration and development direction above the slope will be traced to the main body belt of the diversion channel. Below the slope, the sand debris flow sand body should be traced to the lake center.

The origin analysis of sand bodies in the Upper Triassic Yanchang Formation of the Ordos Basin was carried out, on the basis of the field geological investigation, elaborate core observation and characterization, and analyses of seismic reflection characteristics and systematic sampling and testing. A new sedimentary facies, namely the beach bar sand body, was identified in the Yanchang Formation. In the outcrop, the geometric shape with a flat base and a convex top is seen. Linear conformity is found between the base of the sand body and the underlying lacustrine shale, and markers of exposure are observed at the top. Various sedimentary structures attributed to wave action are developed within the sand body, with lack of erosion and filling structures. The single sand body presents inverse grading from bottom to top, while the compositional maturity of the beach bar sand formed in one stage gradually increases upwards and reaches its maximum at the top of the bar. The grain size probability curve is mainly triple-segmented with "double saltation load and single suspended load". In terms of seismic reflection, the beach bar sand shows growing events, discontinuous amplitudes, and an external form of seismic unit with a flat base and convex top. The main controlling factors of formation and preservation of beach bar sands were discussed, which are preliminarily concluded to be the basal topography of the lake basin, the transition of the stable lake coastline, etc. In the Chang8(2) sub-stage, a vast favorable development belt of beach bar sands, parallel to the coastline, exists in the western and southern parts of the Ordos Basin. The area, which meets the requirement of formation of large-scale reservoir bodies, is a promising major oil and gas reserve supplement.

在全国大力开展创新创业教育背景下,理工科院校专业类基础课程教学改革如何走出一条适应时代发展、符合自身学科专业特点的道路,成为目前亟待解决的问题.将创新创业教育融入专业基础课理论教学,增加学科前沿新技术和发展动态介绍,增加创新项目训练,增加具有实践性的考核内容,是该类高校的普遍做法.本文结合学校实际,以《结晶学与矿物学》课程为例,依托课程建设、实验室建设以及师资队伍建设,探索将课内教学、网络课堂教学、课外延伸教学与创新创业实践教学相互联系的教学模式,培养学生创新创业能力的目的.