The metallogenic age of sandstone-type uranium deposits has always been a scientific problem to be solved in uranium exploration. This paper proposes a method combining the homogenization temperature of secondary fluid inclusions with the apatite （U-Th）/He dating method to determine the metallogenic age related to fluid trapping. The dates of apatite （U-Th）/He can be used as the lower limit of the metallogenic age when the closure temperature of apatite （U-Th）/He is less than the homogenization temperature of the secondary fluid. The samples of the uranium deposits in the Qianjiadian sag show that the homogenization temperatures of secondary fluid inclusions in the ore-bearing horizon are about 83-204 ℃ with a peak of 110-115 ℃， and the apatite （U-Th）/He dates in the same horizon vary between 29.0 ± 1.5-41.8 ± 2.7 Ma. Because the homogenization temperatures of secondary fluid are greater than the closure temperature of apatite （U-Th）/He （75 ± 5 ℃）， the dates of apatite （U-Th）/He （29.0 ± 1.5-41.8 ± 2.7 Ma） are considered as the lower limit of the metallogenic age.

Distinguishing between shoal-water deltas and shore-shallow lake beach-bars is challenging, creating a widespread problem for bar-scale reservoir architecture analysis and ultimately affecting oilfield development. Using the Miocene Upper Ganchaigou Formation in the Z7 and Z401 wellblocks of the Zhahaquan oilfield in the Qaidam Basin as an example, this study examines the differences between mouth bars and beach-bars and establishes an architectural model for mouth bars in a shallow water environment. The main methods used in this study include grain size analysis, architecture analysis, and well-tied single sandbody correlation. Passega's C-M diagram and G.M. Friedman's skewness-standard deviation plot provide reliable criteria for distinguishing mouth bars from beach bars. Architectural analysis is applied to identify architectural units and to establish their relationships with corresponding microfacies. A connected single sandbody-characterized by a single, unified oil-water contact-serves as an effective basis for well-to-well correlation and for interpreting 4th-order architectural units. Two conclusions are drawn. First, grain size analysis shows that rivers dominated the bars in the Z7 and Z401 wellblocks, with lesser influence from waves, indicating that they are mouth bars. Second, architectural analysis shows that there are three levels of architectural units: a 5th-order unit represented by a compound mouth bar formed through the superimposition of multiple single mouth bars; 4th-order units consisting of individual mouth bars, including those partially truncated by distributary channels; and 3rd-order units comprising mouth bar accretion bodies and individual distributary channels. Well-tied sand body correlation, architectural analysis, and microfacies interpretation of III-5-2-2 indicate that six single mouth bars are stacked in an imbricated, lamellar pattern. These bars prograded lakeward sequentially and were intermittently incised by distributary channels as the shoreline migrated toward the lake under an arid climate, shoal water, and a gentle slope. The results of this case study are helpful to distinguish mouth bars from beach-bars and for conducting architectural analysis. They offer valuable guidance not only for Zahaquan, Gasikule, and other oilfields in the Qaidam Basin but also for those that contain shoal-water delta systems in other clastic basins. (c) 2025 Sinopec Petroleum Exploration and Protection Research Institute. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Magmatic activity is crucial for identification of the tectonic framework of the ancient oceanic crust. In this study, systematic investigation, including a field survey, zircon LA-ICP-MS U-Pb dating, and whole-rock geochemical analysis, has been carried out on the intrusive quartz- and granodiorites within the Meso-Tethyan Shiquanhe Ophiolitic M & eacute;lange (SQM), Tibet. Zircon U-Pb dating yields the weighted mean ages of 174.7 +/- 1.4 Ma (quartz diorite) and 178.9 +/- 1.2 Ma (granodiorite), respectively, demonstrating the Early Jurassic formation age. The quartz diorite samples are metaluminous (A/NKC = 0.77-0.95) (molar/Al2O3/(CaO + Na2O + K2O)), while the granodiorite samples are weakly peraluminous (A/NKC = 0.95-1.21), and both of them exhibit tholeiitic to calc-alkaline geochemical characteristics and can be classified as I-type granites. The right-dipping rare-earth element (REE) patterns, enrichment in large ion lithophile elements (LILEs: Rb, Ba, Th), and depletion in high-field-strength elements (HFSEs: Nb, Ta, Ti), as well as relatively high (La/Yb)N ratios, are features compatible with an island arc setting. Combined with previous works, we suggest that the Shiquanhe ophiolitic m & eacute;lange not only preserves records of mid-late Jurassic island arc magmatic activity but also contains evidence of island arc magmatism from the late Early Jurassic.

The paleo-geothermal gradient is a crucial parameter for converting the thermal history to the exhumation history. However, the precise estimation of this parameter has been a challenge. This paper presents a simple two-step method to model the paleo-geothermal gradient using low-temperature thermochronology. (1) It uses the Monte Carlo approach to generate thermal histories in a vertical section randomly and calculates the entire thermal history within the goodness-of-fit thresholds based on different paleo-geothermal gradients. (2) It selects the optimum paleo-geothermal gradient by comparing the entire thermal history within different goodness-of-fit thresholds. We validated the method with apatite (U-Th)/He and fission track data collected from two drill cores in the Haiyuan-Liupanshan region. The result revealed that the best-fit paleo-geothermal gradient was ∼42 °C/km during the Early Cretaceous–Miocene and has decreased rapidly to 20 °C/km since ∼10 Ma. The crust thickening in the study area may explain the rapid reduction in the paleo-geothermal gradient since ∼10 Ma. Our results are consistent with earlier studies in the region, suggesting that our simple and more intuitive approach provides an alternative method for paleo-geothermal gradient modeling.

The Asian monsoon has a large influence range and a significant impact on the lives of nearly half of the world's population. Yet, the origins and evolutionary processes of the Asian monsoon remain elusive. The rain shadow effect serves as a pivotal indicator of the monsoon's trajectory, while paleotopography reconstruction aids in ascertaining the existence or absence of this effect. The Yunkai Mountains, among the highest mountain ranges in southern China, constitute a natural barrier impeding the northward expansion of the warm and humid Asian monsoon. The topography can provide critical information on the onset and development of the Asian monsoon. We utilized apatite and zircon (U-Th)/He data collected from a Gaozhou-Luoding horizontal cross-section to reconstruct the two-dimensional paleotopography of the Yunkai Mountains and determine the mean exhumation rates. The results show the following: (1) The Yunkai Mountains reached a maximum elevation of similar to 3.4 km around 80 Ma, followed by an asymmetrical decrease. (2) The relatively high exhumation rate of the NE segment during 80-40 Ma may be linked to the thermal extensional tectonics, whereas the gradual exhumation rate and significant elevation reduction of the SW segment since 40 Ma were likely associated with the impact of the Asian monsoon or fault activity. (3) No rain shadow effect existed in the Yunkai Mountains in the Paleocene. The climate boundary near the Yunkai Mountains in the Paleocene was most likely the northern boundary of the Intertropical Convergence Zone. Therefore, we conclude that the Asian monsoon formed after the Paleocene.

Back-arc basins are key sites for oceanic lithosphere formation and consumption at convergent plate boundaries, and their formation and subduction processes can be highly variable. The tectonic setting and evolution of the Meso-Tethys Shiquanhe-Jiali ophiolite sub-belt (SJO sub-belt) within Bangong-Nujiang Suture Zone (BNSZ), central Tibet, are disputed for the complex rock composition and ages. In this paper, we present geochronology, geochemistry and field observations on the Shiquanhe ophiolite, providing a representative ophiolite example in the western end of SJO. Based on investigation of the petrogenesis and tectonic setting of different rock types, combined with the U-Pb dating, we propose a two-stage subduction model for explaining the tectonic evolution of SJO as well as the wither away of a back-arc basin. Geochemical and geochronological data indicate that the ca. 183 Ma LAN (north of Lameila) gabbros formed in the forearc setting and represent the early-stage subduction of the Bangong Meso-Tethys. This subduction induced the back-arc spreading recorded in the ca. 170 Ma gabbros and lower pillow basalts of PL-SDN (Pagelizanong-Shiquanhe Dam Nan) ophiolitic fragments in the Shiquanhe ophiolite. The basaltic lavas overlying the lower basalts, represented by the ca. 168-164 Ma diabasic and boninite dikes have forearc characteristics, and they represent the back-arc basin subduction initiation at a late stage. This work thus recovered the multiple tectonic evolution of SJO sub-belt and emphasise the importance of the back-arc basin subduction in the evolution of ancient oceans.

The Bongor Basin is an important petroliferous basin in the Western and Central African rift system. The basin's evolution history is featured with a strong tectonic inversion during the Late Cretaceous, which resulted in its unique basin structure and hydrocarbon accumulation pattern. However, due to the complex process of repeated cooling and heating, single sample bedrock thermochronology can hardly provide accurate constraints to its thermal evolution history. In this paper, nine granitic core samples from the crystalline basement in five wells on the northern slope of the Bongor Basin were analyzed using multiple thermochronological methods (apatite UTh/He, apatite fission tracks and length distribution, apatite U-Pb dating) as well as vertical profiles to obtain a more accurate thermal history. The results show that the samples from all five wells underwent four stages of thermal history: from similar to 600 Ma to 135 Ma, the samples cooled continuously from 600 degrees C to near-surface temperatures; from similar to 135 Ma to 100 Ma, the samples were heated rapidly; from 100 Ma to 60-80 Ma, the samples cooled rapidly; and after that, the samples experienced slow differential heating and cooling. The thermal history results show that the key time for the strong inversion of the Bongor Basin was between 80 and 90 Ma when the basin was uplifted and exhumed as a whole, while samples in different fault blocks underwent differential uplift and subsidence since the Paleogene.

Fission-track dating is a widely used thermochronological technique. The traditional manual identification of fission tracks under a microscope is time-consuming and susceptible to counting errors. A novel deep learning-based method was proposed to detect fission tracks automatically. Our method consists of the following steps. 1) Utilizing the Mask Region-based Convolutional Neural Network algorithm to locate fission tracks and extract their boundary coordinates. 2) Using ellipses to fit the fission tracks’ boundary coordinates. 3) Analyzing the fitted ellipse parameters to handle overlapping tracks. 55 spontaneous fission-track images were utilized for training and 15 images for testing. The algorithm provided excellent detection performance for most samples, with few omission and commission errors. These results indicate that the method has significant potential for automated fission-track identification and distinguishes between overlapping and single tracks.

Based on the analysis of the fluid inclusion homogenization temperature and apatite fission track on the northern slope zone of the Bongor Basin in Chad, this paper studied the time and stages of hydrocarbon accumulation in the study area. The results show that: (1) The brine inclusions of the samples from the Kubla and Prosopis formations in the Lower Cretaceous coexisting with the hydrocarbon generally present two sets of peak ranges of homogenization temperature, with the peak ranges of low temperature and high temperature being 75–105 °C and 115–135 °C, respectively; (2) The samples from the Kubla and Prosopis formations have experienced five tectonic evolution stages, i.e., rapid subsidence in the Early Cretaceous, tectonic inversion in the Late Cretaceous, small subsidence in the Paleogene, uplift at the turn of the Paleogene and Neogene, and subsidence since the Miocene, in which the denudation thickness of the Late Cretaceous and after the turn of the Paleogene and Neogene are ~1.8 km and ~0.5 km, respectively. The cumulative denudation thickness of the two periods is about 2.3 km; (3) Using the brine inclusion homogenization temperature coexisting with the hydrocarbon as the capture temperature of the hydrocarbon, and combining with the apatite fission track thermal history modeling, the result shows that the Kubla and Prosopis formations in the Lower Cretaceous on the northern slope of the Bongor Basin have the same hydrocarbon accumulation time and stages, both of which have undergone two stages of hydrocarbon charging at 80–95 Ma and 65–80 Ma. The first stage of charging corresponds to the initial migration of hydrocarbon at the end of the Early Cretaceous rapid sedimentation, while the second stage of charging is in the stage of intense tectonic inversion in the Late Cretaceous.

Due to limited exposure of the Precambrian rocks in the Tibetan Plateau, their affinities and evolutions are inadequately studied. Here we report the newly identified Neoproterozoic metabasites (including metagabbros and metadolerites) at the western end of the Bangong-Nujiang suture zone (BNSZ) and the west part of the North Lhasa terrane. The Rutong Dong (RTD) metagabbros and Shiquanhe Nan (SQN) metadolerites yield zircon U-Pb ages of 838 Ma and 748 Ma, respectively. The RTD metagabbros are tholeiitic and exhibit both MORB- and arc- like geochemical characteristics, and we consider these to have formed in a back-arc basin setting. Combined with positive zircon epsilon Hf(t) Hf (t) (+6.3 +6.3 to +13.8) and whole-rock epsilon Nd(t) Nd (t) (+4.4 +4.4 to +5.3) values, the geochemical features of the RTD metagabbros indicate that they originated from a depleted mantle source enriched by subductionrelated components (e.g., Th and U). The SQN metadolerites are mainly of transitional character (between tholeiitic and calc-alkaline), as well as representing typical calc-alkaline basalts. Their arc-like geochemical characteristics, as well as low positive whole-rock epsilon Nd(t) Nd (t) (+1.7 +1.7 to +3.4), and positive zircon epsilon Hf(t) Hf (t) (+4.3 +4.3 to +5.9) values, indicate generation by partial melting of an enriched subduction components modified mantle in an arc- type setting. Based on previous research, we propose that the North Lhasa terrane likely separated from India at ca. 925-860 Ma by the opening of the Mozambique Ocean. As the subduction zones were active at ca. 838-730 Ma in this ocean, a series of subduction-related magmatic events occurred, that is recorded in this study of the Rutong-Shiquanhe region, and other parts of the BNSZ and North Lhasa terrane. Consequently, we suggest that the BNSZ not only preserves information of the Meso-Tethys but also retains geological records of the Neoproterozoic Mozambique Ocean.

Deciphering the interactions between tectonic and exhumation processes in the Tanggula Mountains (centralnorthern Tibetan Plateau) can provide insights into the processes of the Tibetan plateau uplift and its geomorphic evolution. In this study, we present new detrital apatite fission track (AFT) data from Cenozoic sediments of the Tuotuohe Basin (northeastern part of the Qiangtang terrane) and its periphery (including the Tanggula Mountains), with the aim to reconstruct the cooling history of the Tanggula Mountains during the Cretaceous and the Cenozoic era. Our results show that the provenance of detrital material evolved in the Tuotuohe Basin and highlight that previously deposited sediments were recycled into the Tuotuohe Basin at similar to 27.5 Ma. The data further outline that the Tanggula Mountains and the Tuotuohe Basin experienced three major phases of tectonic uplift and exhumation: 122-106, 65-54, and 44-35 Ma. These exhumation-induced cooling phases might be related with three phases of primary tectonic activity, i.e., the collision between the Qiangtang and Lhasa terranes (central part of the Tibetan Plateau) that started during the Early Cretaceous, the collision of the Indian and Eurasian plates in the Early Cenozoic and finally, the "hard collision (the Indian and Eurasian continents)" that occurred during the Early Eocene-Oligocene.

The East Asian monsoon is the largest periodic airflow on Earth and significantly affects the climate of East Asia. However, considerable controversy exists about the onset timing of the East Asian monsoon. As one of the southern barriers blocking the northward movement of the warm and humid airflow, the Nanling Range has likely recorded key topographic information related to the East Asian monsoon onset and development. We used apatite and zircon (U-Th)/He data obtained from the Shaoguan-Guidong horizontal cross-section to reconstruct the two-dimensional (2-D) paleotopography of the Nanling Range on a long-term scale. Four vertical profiles in Shulouqiu, Erjian, Sanfenshi, and Leiwangdian were used to constrain the exhumation history of the Nanling Range. The result revealed the following: 1) The drainage divide began to move from south to north at 80 Ma. At 80 Ma, the south segment of the cross-section reached a peak elevation of -3.6 km. The asymmetric topography experienced a rapid elevation (and relief) decrease from 80 Ma to 40-30 Ma. The four vertical profiles also experienced increased cooling and high exhumation rates from 100 Ma to 40-30 Ma. 2) The south segment experienced more rapid exhumation than the north segment from 80 Ma to 40-30 Ma. The rapid exhumation of the south segment during the Late Cretaceous-Paleocene is probably related to the activity of the Nanxiong Fault, and the rapid exhumation of the south segment during the Eocene probably results from the onset of the East Asian Monsoon.

PURPOSE:The aim of this study was to analyze the characteristics of CT-measured intersection angle (FB-BNLD) between the frontal bone and bony nasolacrimal duct and to provide suggestions for treating primary acquired nasolacrimal duct obstruction (PANDO) patients in West China. METHODS:Three hundred and nine participants' CT were, respectively, evaluated with RadiAnt DICOM Viewer. We defined the FB-BNLD angle >0° as the anterior type and the FB-BNLD angle ≤0° as the posterior type. RESULTS:The mean FB-BNLD was -2.52° (95% CI, -3.16° to -1.88°) across all participants, of whom 37.2% were of the anterior type and 62.8% of the posterior type. Approximately 65.0% of the female patients had a posterior FB-BNLD type, and 54.2% of the male patients had an anterior FB-BNLD type (p = .002). Posterior FB-BNLD was the dominant type in the PANDO and control groups (p = .011), and the angle of FB-BNLD was statistically different in both groups (PANDO group, -2.54° to -0.71°; control group, -4.42° to -2.67°; p < .001). Among the male participants, the type of FB-BNLD differed between the two groups (p = .036), with differences in the angle of FB-BNLD (PANDO group, 0.59° to 5.13°; control group, -4.08° to 1.89°; p = .034). There was no difference in the type of FB-BNLD in female participants between the two groups (p = .051). CONCLUSION:The present study revealed individual differences in the type of FB-BNLD, with anterior-type majority in males and posterior-type dominance in females. Evaluating the FB-BNLD type on CT can provide a fast method for knowing the nasolacrimal duct condition during planning for lacrimal manipulation.

The coastal mountain system (CMS) of southeastern China has been a natural place to study paleotopographic changes primarily due to its marked topographical contrast since the Late Cretaceous. For a quantitative reconstruction of the paleotopographic evolution of the CMS, this paper provides key information from along the Ningde-Jianyang and Huilai-Longchuan cross-sections using apatite (U-Th)/He (AHe) and zircon (U-Th)/He (ZHe) data combined with thermal history and paleotopographic modeling. For the Ningde-Jianyang section, the AHe dates are in the range of 44.3-70.8 Ma, and the ZHe dates are between 58.5 and 102.9 Ma. For the Hui-lai-Longchuan section, the resulting AHe dates are in the range of 37.9-73.8 Ma, and ZHe dates are between 65.5 and 119.7 Ma. The modeling results suggest that: 1) the CMS had an asymmetric topography during the Late Cretaceous with the SE segment being significantly higher (peak elevation = 3.8 km) than the NW segment (peak elevation =-2 km). The marked decreases in elevation and relief of the CMS occurred during 80-40 Ma, fol-lowed by relatively minor topographic changes since-40-30 Ma; 2) The SE segment of the southern CMS experienced significantly faster exhumation (-0.44 km/Myr) than northern CMS (0.16 km/Myr) during 70-60 Ma, which was probably related to thinning of the crust and orogenic collapse linked to the initial-rifting of the South China Sea; 3) The SE segment of southern CMS experienced slower exhumation than northern CMS during 60-40 Ma, likely resulting from the lower elevations in the southern CMS than in the northern CMS during 60-40 Ma.

Low temperature thermochronology plays a key role in the study of tectonic evolution of the upper crust. The general application of thermal history modelling of apatite fission-track analysis requires both the parameters of the apparent age together with the confined track-length distribution of the spontaneous tracks. However, obtaining length data is relatively easy and does not require either irradiation or LA-ICP-MS commonly used for determining the uranium content of the grains for age dating. This leads to a shorter laboratory process. For this purpose, based on apatite U-Th/He method, this paper attempts to decouple apatite fission-track age from apatite fission-track length, and then combine the lengths with the respective apatite U-Th/He age to model the thermal history. Therefore, experiments were designed and conducted using a new program "Low-T Thermo". Results of this modelling are presented from the following experiments: apatite fission-track age combined with apatite U-Th/He age; apatite fission-track confined track-length distribution plus apatite U-Th/He age. The modelling precision using this method is related to the relative errors of the apatite U-Th/He ages and the helium diffusion model. This combination of apatite fission-track length and apatite U-Th/He ages has not been implemented before but is presented here as an alternative way of determining thermal histories without the addition of apatite fission-track ages.

The East Asian monsoon impacts the livelihood of billions of people and also influences global climate change, yet its evolution is associated with considerable controversy. The topographic reconstruction of the LuliangTaihang region can provide a valuable topographic record of the East Asian monsoon development. In this study, we employed apatite and zircon (U-Th)/He data to reconstruct the two-dimensional (2-D) paleotopography of the Fangshan-Xiyang horizontal transect and the one-dimensional exhumation evolution of seven vertical profiles in the Luliang-Taihang region. The west segment of the 2-D transect reached a peak elevation of -3.7 km at -80 Ma. The 2-D results revealed that the watershed moved in 80 Ma. Furthermore, a rapid decrease in elevation (and relief) of the topography occurred during the Late Cretaceous in the west segment of the 2-D transect. This was attributed to the Huyanshan Fault activity, which may be related to the collision between the Okhotomorsk Block and East Asia in the Late Cretaceous. There was also a significant elevation reduction and exhumation acceleration for the east segment of the 2-D transect during the Late Oligocene-Middle Miocene, which is probably related to the effects of the East Asian monsoon. The result implies that the Luliang-Taihang region may have played an important role in blocking humid and warm Pacific air into the interior of East Asia after the East Asian monsoon expanded northwards into North China.

如何提高高等学校专业课的教学质量,一直是高等学校专业课教学面临的难题之一."新懂趣用"的教学思想,认为在本科专业课的教学过程中,应尽量保证教学内容要让学生耳目一新,教学难度上要保证学生基本听懂,教学方式上要有趣味性,教学目标应以学以致用为准.这四点在整个专业课教学周期内合为一个整体,任何一部分都不可或缺,才能在系统的专业教学过程中达到良好的教学效果.通过将上述教学思想应用于地质学专业野外教学实践,为相关教学研究提供参考借鉴.

本科专业课教学过程中,毕业设计指导是本科教学的最后一个重要环节.与理论教学不同的是毕业设计不是教授理论而是激发学生的潜力,帮助他们开展研究,故而强调指导方案的设计与提前布局是十分重要的.针对本科毕业设计指导提出了五步走的方案,即通过因人设题、计划详尽、有样可学、不断鼓励及耐心对待等方法指导本科毕业设计,具体来说就是根据学生兴趣点精准设置研究方向、准备详尽的研究步骤及进度安排、让本科生与研究生一起从事研究、不断给学生做思想工作以及耐心对待学生.提出本科毕业设计指导五方略流程,以期为相关教学研究提供参考.

The East China Sea Basin is an ideal area for studying the subduction processes linked with this section of the active West Pacific continental margin. The initial rift time associated with the opening of the East China Sea Basin remains strongly controversial. This paper provides a perspective based on the apatite and zircon fissiontrack analyses of the Changle-Nan'ao Belt, located on the coastal mainland of eastern China. The results reveal a period of rapid exhumation of this belt, trending from 86 Ma in the north to -66 Ma in the south. From -66 Ma until the present exhumation was very slow. The data and their thermal history modeling results imply that the initial rift time of the East China Sea Basin most likely occurred at 80-70 Ma. The younging trend observed from the north to the south of the study area continues along the coastal margin to the northwestern margin of the South China Sea. This suggests the presence of a diachronous rift opening from the southwestern East China Sea during the Late Cretaceous southwards, and to the northwestern South China Sea during the Late Cretaceous-Paleogene. The rapid exhumation is coincident with the rapid decrease in plate velocity of the Izanagi Plate, Pacific Plate, and Neo-Tethyan and Indian Plate during the Late Cretaceous-Paleogene.

Thermal history modeling based on low-temperature thermochronological data is widely used in the study of geology. Despite its common applications, several problems remain easy to ignore yet should not be overlooked in the execution of such models. This paper describes four key problems of thermal history modeling, namely, (1) is the best-fit thermal history the best? (2) Is the date constraint box a suitable constraint? (3) Does the bimodal distribution of the apatite fission track confined track length absolutely correspond to the cooling reheating model? (4) Is the whole thermal history path credible? Counterexamples are then provided to stress the importance of accounting for these problems in the application of thermal history modeling. Acknowledging the uncertainty and considering the geological constraints are recommended to improve the accuracy of thermal history models. Moreover, thermal historical intervals with high credibility and strong constraint ability are recommended to interpret the selected geological phenomenon.