Assessing vegetation dynamics impacted by climate change in the southwestern karst region of China with AVHRR NDVI and AVHRR NPP time-series

The relationship between climate change and vegetation dynamics in the southwestern karst region of China has been identified by recent studies. Based on previous researches and AVHRR (Advanced Very High Resolution Radiometer) GIMMS (Global Inventory Monitoring and Modeling Studies) NDVI (Normalized Difference Vegetation Index) (1982–2003) and AVHRR GloPEM (Global Production Efficiency Model) NPP (Net Primary Production) (1981–2000) datasets, vegetation dynamics impacted by climate change in the southwestern karst region of China were assessed. The results show that: (1) since the early 1980s, both vegetation cover density and net primary production have insignificant ascending tendencies. However, the inter-annual variation rates of vegetation indexes have apparent spatial differentiations; (2) the correlation coefficients between the inter-annual variations of vegetation indexes and the inter-annual variations of climate factors vary geographically; (3) as indicated by NDVI and NPP, various vegetation types have different responses to climate change, and the annual mean temperature variation has more significant impact on vegetation dynamics than the annual precipitation variation in the study area; (4) distribution laws of correlation coefficients between the inter-annual variations of vegetation indexes and the inter-annual variations of climate factors in different climate conditions are apparent. All these findings will enrich our knowledge of the natural forces which impact the stability of the karst ecosystems and provide scientific basis for the management of the karst ecosystems.     

西南天山前寒武纪基底时代和特征：锆石U—Pb年龄和Nd—Sr同位素组成

采用锆石U-Pb定年方法,精确测定了西南天山木扎尔特群花岗片麻岩的结晶锆石年龄为（707±13）Ma(MSWD=0.33)。元素地球化学特征和低的ε     

中国西南部特提斯构造域浅成低温热液型金矿分类及时空分布特征

中国西南部特提斯构造域浅成低温热液型金矿床划分为火山-次火山热液型金矿床、地下热卤水型金矿床和火山热泉型金矿床3个大类及7个亚类.研究了各类型金矿的地球化学特征,在此基础上论述了区内浅成低温热液型金矿床的时空分布,划分出6个成矿区和21个成矿带.     

晋西南峨嵋台塬的岩溶水系统及岩溶水资源潜力

本文通过分析峨嵋台塬的地质结构和岩溶水补给的自然条件,提出:(1)峨嵋台塬岩溶水具独立的地下水系统特征,北边界为里望断裂,南边界为临猗断裂,西边界为沿黄河东岸延展的夹马口—小梁断裂,东边界为稷王山东麓泥页岩带和变质岩体;(2)岩溶水主要来自稷王山裸露区大气降水,少量排向河津—侯马盆地和运城盆地,大量沿临猗断裂带向黄河方向迳流排泄,排泄量不到东王岩溶泉流量的10%;(3)峨嵋台塬岩溶水潜力有限。     

Southwest African climate independent of Atlantic sea surface temperatures during the Younger Dryas

To investigate land–sea interactions during deglaciation, we compared proxies for continental (pollen percentages and accumulation rates) and marine conditions (dinoflagellate cyst percentages and alkenone-derived sea surface temperatures). The proxies were from published data from an AMS-radiocarbon-dated sedimentary record of core GeoB 1023-5 encompassing the past 21,000 years. The site is located at ca. 2000 m water depth just north of the Walvis Ridge and in the vicinity of the Cunene River mouth. We infer that the parallelism between increasing sea surface temperatures and a southward shift of the savanna occurred only during the earliest part of the deglaciation. After the Antarctic Cold Reversal, southeast Atlantic sea surface temperatures no longer influenced the vegetation development in the Kalahari. Stronger trade winds during the Antarctic Cold Reversal and the Younger Dryas period probably caused increased upwelling off the coast of Angola. A southward shift of the Atlantic anti-cyclone could have resulted in both stronger trade winds and reduced impact of the Westerlies on the climate of southwestern Africa.     

Triassic synthems of southern South America (southwestern Gondwana) and the Western Caucasus (the northern Neotethys), and global tracing of their boundaries

Global tracing of the key surfaces of Triassic deposits may contribute significantly to the understanding of the common patterns in their accumulation. We attempt to define synthems – disconformity-bounded sedimentary complexes – in the Triassic successions of southern South America (southwestern Gondwana, Brazil and Argentina) and the Western Caucasus (the northern Neotethys, Russia), and then to trace their boundaries in the adjacent regions and globally. In southern South America, a number of synthems have been recognized – the Cuyo Basin: the Río Mendoza–Cerro de las Cabras Synthem (Olenekian–Ladinian) and the Potrerillos–Cacheuta–Río Blanco Synthem (Carnian–Rhaetian); the Ischigualasto Basin: the Ischichuca-Los Rastros Synthem (Anisian–Ladinian) and the Ischigualasto–Los Colorados Synthem (Carnian–Rhaetian); the Chaco–Paraná Basin: the Sanga do Cabral Synthem (Induan), the Santa Maria 1 Synthem (Ladinian), the Santa Maria 2 Synthem (Carnian), and the Caturrita Synthem (Norian); western Argentina: the Talampaya Synthem (Lower Triassic) and the Tarjados Synthem (Olenekian?). In the Western Caucasus, three common synthems have been distinguished: WC-1 (Induan–Anisian), WC-2 (uppermost Anisian–Carnian), and WC-3 (Norian–lower Rhaetian). The lower boundary of WC-1 corresponds to a hiatus whose duration seems to be shorter than that previously postulated. The synthem boundaries that are common to southwestern Gondwana and the Western Caucasus lie close to the base and top of the Triassic. The Lower Triassic, Ladinian, and Upper Triassic disconformities are traced within the studied basins of southern South America, and the first two are also established in South Africa. The Upper Triassic disconformity is only traced within the entire Caucasus, whereas all synthem boundaries established in the Western Caucasus are traced partly within Europe. In general, the synthem boundaries recognized in southern South America and the Western Caucasus are correlated to the global Triassic sequence boundaries and sea-level falls. Although regional peculiarities are superimposed on the appearance of global events in the Triassic synthem architecture, the successful global tracing suggests that planetary-scale mechanisms of synthem formation existed and that they were active in regions dominated by both marine and non-marine sedimentation.     

老万场红土型金矿开发与生态环境关系简析

文章简要分析了老万场喀斯特红土型金矿的开采对该区域生态环境的影响，分析了影响因素，对治理的措施和方法进行了讨论，指出治理对该区生态环境的重要意义。     

Influence of transboundary air pollution on air quality in southwestern China

Air pollution is a grand challenge of our time due to its multitude of adverse impacts on environment and society,with the scale of impacts more severe in developing countries,including China.Thus,China has initiated and implemented strict air pollution control measures over last several years to reduce impacts of air pollution.Monitoring data from Jan 2015 to Dec 2019 on six criteria air pollutants(SO2,NO2,CO,O3,PM2.5,and PM1o)at eight sites in southwestern China were investigated to understand the situation and analyze the impacts of transboundary air pollutants in this region.In terms of seasonal variation,the maximum concentrations of air pollutants at these sites were observed in winter or spring season depending on individual site.For diurnal variation,surface ozone peaked in the afternoon while the other pollutants had a bimodal pattern with peaks in the morning and late afternoon.There was limited trans-port of domestic emissions of air pollutants in China to these sites.Local emissions enhanced the concen-trations of air pollutants during some pollution events.Mostly,the transboundary transport of air pollution from South Asia and Southeast Asia was associated with high concentrations of most air pollu-tants observed in southwestern China.Since air pollutants can be transported to southwestern China over long distances from the source regions,it is necessary to conduct more research to properly attribute and quantify transboundary transport of air pollutants,which will provide more solid scientific guidance for air pollution management in southwestern China.     

新疆西南天山哈布腾苏一带高压-超高压变质基性岩的地球化学特征及其构造意义

新疆西南天山哈布腾苏地区的高压-超高压变质基性岩(榴辉岩和蓝片岩)主要以形态各异的岩块或构造透镜体形式产于其围岩变质沉积岩石榴多硅白云母片岩中.本文对这些变质基性岩进行了详细的岩石学、矿物学和地球化学研究,并对其原岩性质及区域构造演化进行了讨论.地球化学分析结果显示其原岩成分主要为拉斑玄武岩和少量碱性玄武岩.榴辉岩原岩可进一步划分为N-MORB(正常洋中脊玄武岩)、E-MORB(富集洋中脊玄武岩)和OIB(洋岛玄武岩)三种类型,而蓝片岩为OIB型.第一种榴辉岩具低的TiO2(1.00％ ～ 1.08％)、P2O5 (0.09％ ～0.15％)和∑REE(35.98×10-6 ～ 43.51×10-6)含量以及低的LREE/HREE(1.35 ～ 1.43)和(La/Yb)N(0.63 ～0.71)比值等特征,具有N-MORB属性,暗示其原岩可能来源于亏损的地幔源区,形成于大洋环境;第二种榴辉岩具有较高的Ti(TiO2=1.35％ ～2.25％)、P(P2O5 =0.05％ ～0.20％)和∑REE(60.10×10-6～ 77.35×10-6)含量和较高的LREE/HREE(1.25 ～2.43)、(La/Yb)N (0.52～1.52)比值,具有E-MORB特征;第三种榴辉岩TiO2含量为1.16％ ～2.86％,Zr/Y=5.32 ～ 7.78,∑REE=79.12×10-6 ～ 192.1×10-6,LREE/HREE =4.15 ～6.54,(La/Yb)N =3.77 ～9.44,其轻重稀土元素分异明显,显示OIB属性,暗示其原岩可能来源于富集地幔源区.而OIB型蓝片岩则富集TiO2(1.39％～2.86％)和∑REE(88.18×10-6～227.8×10-6)和具有相对高的(La/Yb)N(5.03～9.84)和Zr/Y(4.93 ～9.55)比值,这些特征与OIB型榴辉岩类似,暗示二者可能具有共同的岩浆源区.新疆西南天山哈布腾苏地区具MORB和OIB属性岩石组合的出现揭示该区早古生代曾发育有洋盆,其演化过程中可能受到结晶分异作用以及异源岩浆混合的影响,导致该区的变质基性岩元素地球化学特征具有MORB和OIB的亲缘性,暗示其原岩是在大洋中脊和临近洋岛共同作用背景下形成的.该区榴辉岩和蓝片岩的形成可能与先存洋壳残片经历高压-超高压变质作用及后期构造折返有关.     

The Rio de la Plata craton and the adjoining Pan-African/brasiliano terranes: Their origins and incorporation into south-west Gondwana

The Neoproterozoic to Early Cambrian amalgamation of SW Gondwana through the Brasiliano/Pan-African orogeny is reviewed with emphasis on the role of the Río de la Plata craton of South America in the light of new evidence from a borehole at the eastern end of the Tandilia belt (38°S). U–Pb, Hf and O isotope data on zircon indicate that this un-reworked Palaeoproterozoic craton abuts against a distinct continental terrane to the east (Mar del Plata terrane). The craton is bounded everywhere by transcurrent faults and there is no evidence to relate it to the Neoproterozoic mobile belts now seen on either side. The Punta Mogotes Formation at the bottom of the borehole contains 740–840 Ma detrital zircons that are assigned to a widespread Neoproterozoic rifting event. The data suggest that the Mar del Plata terrane rifted away from the southwestern corner of the Angola block at c. 780 Ma. Negative εHf_t values and δ¹⁸O > 6.5‰ suggest derivation by melting of old crust during a protracted extensional episode. Other continental terranes may have formed in a similar way in Uruguay (Nico Pérez) and southeastern Brazil, where the Schist Belt of the Dom Feliciano orogenic belt is probably a correlative of the Punta Mogotes sequence, implying that the Dom Feliciano belt must extend at least as far as 38°S. A new geodynamic scenario for West Gondwana assembly includes at least two major oblique collisional orogenies: Kaoko–Dom Feliciano (580–680 Ma) and Gariep–Saldania (480–580 Ma), the latter resulting from oblique impingement of the Rio de la Plata craton against the Kalahari craton. Assembly of this part of South-West Gondwana was accomplished before the Ordovician (to Silurian?) siliciclastic platform sediments of the Balcarce Formation in the Tandilia Belt covered the southern sector of Río de la Plata craton.