The southeastern margin of the Tibetan Plateau, formed by the Indian-Eurasian collision, provides an ideal setting for investigating landscape evolution and deep geodynamic processes. The Salween River Canyon provides an exceptional natural setting to investigate tectonic-fluvial coupling mechanisms. We analyzed longitudinal profiles derived from 12.5 m resolution ALOS PALSAR DEM data (Alaska Satellite Facility) from 10 bedrock rivers using stream power models, chi-plot methodology, and linear inversion techniques. Three distinct knickpoint groups (1450-3310 m elevation) were identified across the region. Through systematic analysis of knickpoint distribution, lithology, and precipitation patterns, we demonstrate their predominantly tectonic origin. Using cosmogenic nuclide-derived erosion rates, we constrained the regional erosion coefficient to K=(1.41 +/- 0.11) x 10(-6) m(0.1)/yr. Under the assumption of topographic steady-state conditions maintained over geological timescales, we reconstruct the rock uplift rate history over the past similar to 16 Ma through river profile inversion. It is crucial to distinguish that our inversion results represent rock uplift rates (the vertical movement of rock relative to a fixed reference frame) rather than surface uplift rates (net elevation gain after accounting for erosional losses). In topographic steady-state, rock uplift rate equals erosion rate, while surface uplift approaches zero due to the dynamic equilibrium between tectonic forcing and erosional denudation (England and Molnar, 1990, Willett and Brandon, 2002). Our rock uplift rate reconstruction reveals a complex temporal pattern: significant uplift acceleration during 11-14 Ma, peak rates at similar to 11 Ma, followed by gradual deceleration, and a sharp decline to 0.11 +/- 0.008 mm/yr after 2 Ma. Our findings indicate that erosional destruction of relict landscapes in the Salween Canyon began in the Late Miocene, temporally coinciding with the cessation of southeastern Tibetan Plateau expansion.

The Wanlongshan Zn-Sn polymetallic deposit represents a significant deposit discovered recently in the world-class Dulong super-large Zn-Sn-In polymetallic ore field, situated in proximate to the Tongjie-Manjiazhai ore deposit. The stratiform to lenticular ore bodies are hosted within siliceous carbonate rocks of the Cambrian Tianpeng Formation's second member and exhibit structural control by interlayer fault zones. Despite its importance, the precise timing of magmatic-hydrothermal activity and the associated ore-forming processes remain incompletely constrained, generating considerable debate regarding its genesis. To address these uncertainties, this investigation employs an integrated analytical approach combining garnet U-Pb geochronology, trace element geochemistry of garnet and sphalerite, and in situ sulfur isotope systematics. Geochemical analyses reveal that the garnets are predominantly grossularitic in composition, characterized by distinctive LREE depletion and HREE enrichment patterns that likely reflect the interplay between crystal-chemical constraints and adsorption mechanisms. The subdued europium anomalies suggest mineral formation under conditions of low oxygen fugacity within a weakly oxidizing to reducing environment that was neutral to mildly acidic, where hydrothermal metasomatism proceeded primarily via diffusional processes under restricted water/rock ratios. Geochronological constraints from garnet U-Pb dating yield an age of 88.1 +/- 3.3 Ma (MSWD = 0.98, n = 17), which correlates remarkably well with molybdenite Re-Os ages from the mining district, ore formation ages at Manjiazhai, and the emplacement chronology of the Laojunshan granite. This temporal coincidence strongly indicates synchronicity among skarnization processes, Zn-Sn mineralization, and granitic magmatism. Trace element distributions in sphalerite reveal substantial enrichment in Fe, Mn, and In, with concomitant depletion in Ga, Ge, and Sn. Elemental ratios including Fe/Zn, Zn/Cd, and Ga/In in sphalerite indicate intermediate to high-temperature mineralization conditions. Multiple substitution mechanisms have been identified: Fe, Mn, and Cd incorporate through simple isomorphic replacement of Zn; Pb occurs predominantly as microinclusions; Cu enters as chalcopyrite solid solution; silver likely substitutes through coupled mechanisms involving either Ag+ + Ga3+-* 2Zn2+ or 2Ag+ + Ge4+-* 3Zn2+; gallium exhibits minimal incorporation; while indium predominantly substitutes via Cu+ + In3+ <-> 2Zn2+.The trace element signature of sphalerite differs markedly from patterns characteristic of Mississippi Valley-Type (MVT), Volcanic-Hosted Massive Sulfide (VHMS), and Sedimentary Exhalative (Sedex) Pb-Zn deposits, instead exhibiting geochemical affinities with established skarn deposits worldwide. In situ sulfur isotope analyses yield delta 34S values ranging from 0 to 3.8 %o (mean 2.1 %o, n = 38), consistent with predominant derivation from magmatic reservoirs, confirming that sulfur in the ore-forming fluids originated primarily from magmatic-hydrothermal sources. Collectively, these multiple lines of evidence-chronological, mineralogical, geochemical, and isotopic-provide compelling support for the classification of the Wanlongshan Zn-Sn polymetallic deposit as a classic skarn-type mineralization system.

The Guanfang large-scale W deposit is located in the W polymetallic ore concentration area of Bozhushan in southeastern Yunnan, China. Despite extensive research, the fluid evolution process of the deposit remains ambiguous, leading to controversy regarding its genesis. This study conducted a detailed field geological survey, with systematic sampling of the KT6 orebody, to delineate mineralization stages. Fine mineralogy work, including the use of CL images of scheelite, in-situ LA-ICP-MS trace elements, and Sr isotopes, was carried out on different generations of scheelite formed in various stages. The findings identified the evolution of fluids in the mineralization process, shedding light on the genesis of the deposit. The study revealed four mineralization stages at the Guanfang W deposit: prograde skarn stage, retrograde skarn stage, quartz-sulfide stage, and carbonate-fluorite stage. Different generations of scheelite (Sch I, Sch II, Sch III) were observed in the first three stages, displaying distinct chondrite-normalized REE patterns. The REE of Sch I mainly substituted into the Ca site by REE3+ + □Ca, and there may be a similar substitution of Nb for REE, whereas it is not the main substitution method. The REE of Sch II mainly enter the scheelite lattice in the form of REE3+ + Na+, and there may be a substitution of Nb for REE isomorphism. In the early stage, The REE of Sch III was mainly replaced by Nb for REE isomorphism, while in the later stage, the replacement mode of REE3+ + □Ca coexisted with it. The Mo content in scheelite, along with the corresponding Eu anomalies in both scheelite and garnet, collectively imply that the ore-forming fluids during various mineralization stages were predominantly oxidizing, with only slight reducibility observed in Sch II. The in-situ Sr isotope ratios of scheelite concentrates ranged from 0.7093 to 0.7153, resembling those of the Bozhushan granite, indicating a relationship between W mineralization and granite. In addition, the Y/Ho ratios of scheelite from various mineralization stages exhibit a narrow range (19–31), with a pronounced correlation between the contents of Y and Ho and a similar trend in their variation. This consistency suggests that the Guanfang deposit has undergone a uniform or comparable evolutionary process, implying a stable ore-forming fluid across different mineralization stages.

The nine plateau lake watersheds in Yunnan are important ecological security barriers in the southwest of China. The prevention and control of landslides are important considerations in the management of these watersheds. Taking the Dianchi Lake watershed as a typical research area, a comprehensive modeling and assessment process of landslide susceptibility was put forward. The comprehensive process was based on the weight of evidence (WoE) method, and many statistical techniques were integrated, such as cross-validation, multi-quantile cumulative Student’s comprehensive weight statistics, independence testing, step-by-step modeling, ROC analysis, and ROC-based susceptibility zoning. In this paper, fourteen models with high accuracy and validity were established, and the AUC reached 0.83–0.87 and 0.85–0.88, respectively. In addition, according to the susceptibility zoning map compiled via the optimal model, 80% of landslides can be predicted in the very-high- and high-susceptibility areas, which only account for 19.58% of the study area. Finally, this paper puts forward strategies for geological disaster prevention and ecological restoration deployment.

羊拉铜矿床是三江特提斯构造域金沙江缝合带中段的大型矽卡岩型铜矿床,其成矿过程划分为3个期次5个阶段:①矽卡岩期:矽卡岩阶段和退化蚀变阶段;②石英硫化物期:石英-硫化物阶段和石英-碳酸盐阶段;③表生期:主要是表生氧化阶段.里农矿段揭露矽卡岩期的矽卡岩矿物以石榴子石、透辉石为主,根据野外观察、镜下鉴定结合LA-ICP-MS原位微区分析,可将石榴子石分为两个世代:早期石榴子石(GrtⅠ),以钙铝榴石为主(And24.81Gro72.40～And57.92Gro30.02);晚期石榴子石(GrtⅡ),以钙铁榴石为主(And61.64Gro37.18～And90.96Gro7.81),发育振荡环带;二者均属于钙铁榴石-钙铝榴石系列.石榴子石稀土元素总量总体较低(ΣREE=3.74×10−6～111×10-6),轻、重稀土元素分异明显(LREE/HREE=0.72～31.7),多呈现正Eu异常(δEu=0.83～8.40).GrtⅠ亏损轻稀土元素、富集重稀土元素,稀土元素配分模式为左倾型;GrtⅡ整体上富集轻稀土元素、亏损重稀土元素,稀土元素配分模式为右倾型,GrtⅡ中ΣREE、LREE/HREE和 δEu值高于GrtⅠ.GrtⅠ、GrtⅡ均呈现出亏损Rb、Ba和Sr等大离子亲石元素,富集Ta、Th和U等高场强元素,GrtⅡ中Cu、Mo、Sn及Pb等成矿元素含量明显高于GrtⅠ.石榴子石主量和微量元素含量及变化特征表明:GrtⅡ形成时氧逸度较GrtⅠ更高,且流体更偏中性或碱性;GrtⅠ交代方式以扩散交代为主,GrtⅡ以渗滤交代为主,与铜钼矿化密切相关.与黄铜矿紧密共生的石榴子石LA-sf-ICP-MS U-Pb进行年代学研究,获得年龄为236±5 Ma(MSWD=0.8,n=23),限定羊拉铜矿床的成岩成矿作用时限为晚三叠世早期,与前人研究的第一期花岗闪长岩锆石U-Pb和辉钼矿Re-Os年龄在误差范围内基本一致,进一步佐证羊拉铜矿床成矿作用与第一期岩浆事件密切相关.

Geological hazard susceptibility assessment is an important basis for territorial space planning and geological hazard prevention and mitigation. In order to explore the evaluation method suitable for the geological hazard susceptibility of low hills and gullies in Yunnan plateau, Wuhua District of Kunming, Yunnan Province, China was selected as a typical study area. Eight factors including the engineering geology groups, distance from faults, elevation, slope, direction, curvature, distance from roads and land use covers were selected, and the weight evidence method based on Bayesian theory was applied to evaluate the susceptibility of geological hazards. After performing the Student-T test of the comprehensive evidence weight of each factor, the classification scheme of factors were optimized. The results of vulnerability zoning based on the evaluation of the model established in this paper showed that 89.9% and 9.1% of the geological hazard points fall into high and medium susceptibility areas. The comparative analysis showed that the modeling results are highly consistent with the geological hazards distribution, which better reveals the characteristics of geological hazards susceptibility in the study area. It can provide reference for the planning of geological hazards prevention in Wuhua District and other low hills and gullies areas of Yunnan plateau.

广西大厂黑水沟锌铜矿床的发现是深部找矿工作取得的重大成果,该矿床的围岩蚀变以矽卡岩化为主,研究工作中发现了围岩中典型的矽卡岩矿物符山石,这对该矿床的形成及下一步的找矿工作具有重要的指示意义.符山石主要分布在退化蚀变阶段,属于含水矽卡岩产物,并与矿床的Zn-Cu矿化密切相关,可作为矿床矿化的找矿标志,利用原位LA-ICP-MS技术对符山石的主微量和稀土元素组成进行了分析.结果 表明,区内符山石均富铝,并与区内矽卡岩及深部花岗岩富铝的特征一致;微量元素结果显示符山石中富集大量成矿元素,如Zn、Sn、Bi、W、Ga、Sr等,它们以类质同象的方式置换了晶格中的Mg2+、Fe2+,推测在退化蚀变时期的成矿流体己富集大量的成矿元素,从而为后期的成矿作用提供了有利的环境.稀土元素研究发现,所有符山石均具有与深部隐伏花岗岩近似平行的稀土配分模式,暗示该矿床的形成与深处隐伏岩体具有紧密的联系.

In this paper, taking debris flow in Dongchuan as the research object, nine influence factors are chosen as the selected indices, including the elevation, slope, aspect, relief, curvature, engineering rock group, distance to faults, distance to faults rivers, and land use types, sample data from 144 debris flows in the study area are used to establish the Dongchuan debris flow susceptibility assessment system. Based on the information model and GIS platform, the information vaule of each factor classification is calculated, and the natural discontinuity method is used to divide the debris flow susceptibility into 4 levels: extremely high-prone areas, high-prone areas, medium-prone areas, and low-prone areas in the study area. The results show that the number of debris flow disasters in the extremely high and high-risk areas in the study area accounted for 94.44%, and the AUC value was 0.876, indicating that the selection of evaluation indicators was reasonable, and the information model was suitable for the evaluation of debris flow susceptibility in Dongchuan.

The Chang’an Chong Cu-Mo deposit is located in the Chang’an Cu-Mo-Au ore cluster in the southern Ailaoshan tectonic belt in southwestern China. There are six intrusive bodies in the mining area, among which the No.Ⅱ intrusive body is the largest and most closely related to Cu-Mo mineralization of skarn. The No. 1 main orebody is composed of the No. 1 copper orebody and No. 1 molybdenum orebody, which are distributed in parallel with similar shapes. In this paper, the age of skarn is determined by the LA-SF-ICP-MS U-Pb dating of garnet, and it is nearly consistent with the age of alkaline porphyry in this region (41–32 Ma). Compared with the U-Pb age of zircon from the ore-bearing porphyry and the Re-Os age of molybdenite, the U-Pb age of garnet was consistent with them within error, indicating that they were the same mineralization event, which further proves that the porphyry-skarn Cu-Mo-Au mineralization event along the Ailaoshan-Red River fault zone mainly occurred at 38~32 Ma. In-situ S isotope results show that the δ34S mean values of disseminated pyrite (PyI), pyrite of sulfide veins (PyⅡ) and chalcopyrite (Ccp) in the main mineralization period are 2.35‰, 3.60‰ and 0.55‰, respectively. These δ34S values are similar to those of magma and slightly enriched in δ34S, and the δ34S value of chalcopyrite is mainly concentrated near 0‰, so it can be considered that the S of the ore-forming fluid came from magmatic-hydrothermal fluids. Based on the comprehensive analysis of the regional metallogenic background, deposit chronology and isotope geochemistry, it is concluded that the Chang’an Chong Cu-Mo deposit was formed in an intra-plate post-collision strike-slip environment.

The Guanfang skam-type tungsten deposit is located in the Bozhushan tungsten polymetallic ore concentration area in southeastern Yunnan. It is situated at the junction of three major tectonic units of Yangtze block, Cathaysia block and Indosinian block. Scheelite is disseminated in garnet-pyroxene skams which are generally not in direct contact with intrusive rocks and occur in vein or lenticular forms in host rocks. The accurate determination of petrogenetic and metallogenic age is of great significance for studying the petrogenetic and metallogenic geological background, genesis and metallogenic prediction of the W-Sn deposit in southeastern Yunnan. According to the results of electron microprobe analysis, the garnets are the series of andradite-almandite solid solution. In-situ LA-SF-ICP-MS U-Pb dating of the garnet from the Guanfang deposit yielded a lower intercep Pb-26/U-238 age of 101.3 +/- 5.4Ma ( MSWD = 2.0) and 87.6 +/- 2.3Ma (MSWD = 1.5) in the Tera-Wasserburg Concordia diagram, respectively, suggesting that there may be two stages skam petrogenetic events in Early Cretaceous and Late Cretaceous in this area. The comprehensive study shows that in-situ U-Pb dating of the garnet is feasible to constrain the metallogenic age of skam-type tungsten deposit. Combined with the Late Yanshanian petrogenetic and metallogenic events, we suggest that similar to 88Ma is the main ore-forming period of W-Sn polymetallic deposits in the area, and the ore-forming process is closely related to the contemporaneous granites. similar to 101Ma may be another skam petrogenetic and metallogenic event. This new finding and understanding is of great practical significance for regional prospecting deployment.

Non-uniqueness is always, by nature, the problem we face in inversion processes, and it is caused by the phenomenon of equivalence in field, erroneous, discrete, and finite features in observation and the influence of other sources. Many authors have done lots of researches in this field in order to get more reliable outcomes, and joint inversion is a thriving one where different kinds of data are combined to derive certain information simultaneously or sequentially. One of these studies is that the prior information such as the geological, drilling and seismic data will be used as constraints, while the inversion procedure can be controlled. In this article we use a new method with the goal of better obtaining the three-dimensional density contrast interface. This prior seismic data integrated in the inversion can play a constrained role in the procedure which means that the depth of the Moho interface at the seismic location will be restricted. It thus can provide a credible result. In order to test its effect, this program is applied in a field example—derivation of Moho geometry in Northeast China.

Qiongdongnan Basin is a Cenozoic rift basin located on the northern passive continental margin of the South China Sea. Due to a lack of geologic observations, its evolution was not clear in the past. However, recently acquired 2-D seismic reflection data provide an opportunity to investigate its tectonic evolution. It shows that the Qiongdongnan Basin comprises a main rift zone which is 50-100. km wide and more than 400. km long. The main rift zone is arcuate in map view and its orientation changes from ENE-WSW in the west to nearly E-W in the east. It can be divided into three major segments. The generally linear fault trace shown by many border faults in map view implies that the eastern and middle segments were controlled by faults reactivated from NE to ENE trending and nearly E-W trending pre-existing fabrics, respectively. The western segment was controlled by a left-lateral strike-slip fault. The fault patterns shown by the central and eastern segments indicate that the extension direction for the opening of the rift basin was dominantly NW-SE. A semi-quantitative analysis of the fault cut-offs identifies three stages of rifting evolution: (1) 40.4-33.9. Ma, sparsely distributed NE-trending faults formed mainly in the western and the central part of the study area; (2) 33.9-28.4. Ma, the main rift zone formed and the area influenced by faulting was extended into the eastern part of the study area and (3) 28.4-20.4. Ma, the subsidence area was further enlarged but mainly extended into the flanking area of the main rift zone. In addition, Estimates of extensional strain along NW-SE-trending seismic profiles, which cross the main rift zone, vary between 15 and 39. km, which are generally comparable to the sinistral displacement on the Red River Fault Zone offshore, implying that this fault zone, in terms of sinistral motion, terminated at a location near the southern end of the Yinggehai Basin. Finally, these observations let us to favour a hybrid model for the opening of the South China Sea and probably the Qiongdongnan Basin. © 2013 Elsevier Ltd.

Wavelet multi-scale analysis is applied to the research on Bouguer gravity field and the explanation of tectonic structure and deep faults in northeast China.Based on Bouguer gravity anomaly,the gravity field is decomposed into four scale by multi-scale wavelet decomposition method.Extracting the second and third order details which reflect the anomalies correlated with deep faults and enhancing faults' linear features by calculating the horizontal gradient in different directions.The results indicate 12 deep faults.Meanwhile,the paper interprets the characteristics of deep faults with the power spectrum method and the information of seism distribution,focal mechanism and geology.The result shows that 12 deep faults are divided into two types.One is the suture zone between massifs.The other plays a significant role in distribution and evolution of basin groups.Deep faults system has a predominant direction in NE,NNE and most of faults are strike-slip faults.According to the characteristics of wavelet multi-scale decomposition and the deep faults system,the paper divides the Bouguer gravity in to first-order and secondary anomaly regions and describes the characteristics of their Bouguer gravity fields.Xing' an massif and Erguena massif was first separated.The first-order gravity anomaly regions contains Erguena massif,Xing'an massif,Songnen massif,Kiamusze massif,Huabei massif.The secondary anomaly regions contains Erlian basin,Greater Khingan region,Lesser Khingan region,Songliao basin,Zhangguangcai region,Nadanhada block,Sanjiang basin,Huanan-muling region,Liaotung peninsula region,Huabei massif,Fracture zone.The result depicts the framework of tectonic units in northeast China.