Fractional crystallization processes of magma beneath the Carlsberg Ridge(57°–65°E)

Fractional crystallization of basaltic magma at variable depths in?uences strongly the geochemical compositions of mid-ocean ridge basalts(MORBs), especially at slow-spreading mid-ocean ridges. The Carlsberg Ridge is a typical slow-spreading ridge located in the northwestern Indian Ocean. In this study, we conducted petrological, geochemical and modelling studies of MORBs collected along the Carlsberg Ridge from 57°–65°E to understand the fractional crystallization processes of magma and the controls on variations in MORB geochemistry. Our results show that the mantle sources beneath the Carlsberg Ridge are heterogeneous even on the local scale of a segment; such heterogeneity may be ubiquitous beneath the Carlsberg Ridge. Mantle heterogeneity may be caused by the enriched components resulting in the "DUPAL" anomaly, whereas the ef fect of pyroxenite on mantle heterogeneity is negligible. The parental melts experienced crystallization of olivine, plagioclase and clinopyroxene prior to eruption, which played a signi?cant role in the major and trace element variations in MORBs from the Carlsberg Ridge. The liquid lines of descent(LLDs), deduced from the forward modelling of three parental magma compositions using the Petrolog3 program at pressures between 1 atm and 10 kbar, demonstrate that clinopyroxene joined the olivine and plagioclase cotectic. The over-enrichment in highly incompatible elements relative to LLDs may be caused by the processes of replenishment-tapping-crystallization in magma chambers. The calculated crystallization pressures suggest that parental magmas beneath the Carlsberg Ridge experienced moderateto high-pressure crystallization and that crystallization beneath the slow-spreading Carlsberg Ridge may start at upper mantle depths.     

New findings concerning the Pleistocene Glaciation of the Leh Basin,Ladakh(34°03'N/77°38'E)

Like for most parts of High Asia,researches concerning the Pleistocene landscape evolution of the Leh Basin(34°03' N/77°38' E) have also left contradictions.To push this topic,three up to now unexplored Ladakh Range tributaries of the Leh Basin(Stagmo-,Arzu-and Nang-Valley) have been investigated.U-shaped profiles,transfluence passes,moraine mantled and glacially rounded peaks and ridges,roches moutonnées,glacial flank polishings and ground moraines document the former glaciation of the study area.The ice fillings of these tributaries reached a minimum thickness up to 540 m.Even at the valley outlets and on the orographic right side of the Leh Basin,the glaciation was more than 350 m thick.Based on these empirically extracted results,theoretical snow line considerations lead to the conclusion that the whole Leh Basin was filled up by a former Indus-Valley glacier.An ice injection limited to the nourishment areas of the Ladakh Range valleys could not have caused the reconstructed ice cover(down to 3236 m a.s.l.),which is proved by extended ground moraine complexes.Only an Indus ice stream network(most likely during the LGP),nourished by inflowing glaciers of the Ladakh-and Stok Range,explains the widespread existence of the glacial sediments at the outlets of the investigated valleys.     

Projected Regional 1.50°C and 2.00°C Warming Threshold-crossing Time Worldwide Using the CMIP6 Models

The Paris Agreement aims to limit global warming to well below 2.00°C and pursue efforts to limit the temperature increase to 1.50°C. However, the response of climate change to unbalanced global warming is affected by spatial and temporal sensitivities. To better understand the regional warming response to global warming at 1.50°C and 2.00°C, we detected the 1.50°C and 2.00°C warming threshold-crossing time(WTT) above pre-industrial levels globally using the Coupled Model Intercomparison Project...     

The Mineral Composition and Sources of the Fine-Grained Sediments from the 49.6°E Hydrothermal Field at the SWIR

We used the X-ray diffraction method to determine systematically the mineral phases in bulk sediment samples and acid undissolved residuals of the fine-grained fraction of the surface sediments from the 49.6°E hydrothermal field at the Southwest Indian Ridge(SWIR)and discussed the mineral sources of the surface sediments.The results showed that the surface sediments in this region were composed of calcareous ooze,and calcite was the dominant mineral.The sediments also contained quartz,feldspar,clay minerals,pyroxene,sphalerite,barite,serpentine,and magnetite.The quartz,feldspar,and clay minerals were exogenous minerals that mainly originated from the Namib and Kalahari deserts in southern Africa.The pyroxene,serpentine,magnetite,sphalerite,calcite,and barite were endogenous minerals from weathering of seafloor basement rocks and seafloor hydrothermal activities.The sulfide particles in the sediments were mainly deposited from upwelling plumes.     

Decadal variations of the North Pacific Tropical Water at 137°E

The decadal variations of the North Pacific Tropical Water(NPTW)at 137°E in the western North Pacific Ocean are investigated based on the repeated hydrographic observations along with two global gridded ocean products.The results indicate that the maximum salinity of NPTW experiences significant quasi-decadal variations,having maxima around 1979,1987,1995,2004,and 2012,while minima around1974,1983,1991,1999,and 2008 during the period of interest.The NPTW area also shows similar quasidecadal variation,expanding/shrinking as its maximum salinity increases/decreases at the 137°E section.These variations are induced mainly by changes in the mixed layer salinity in the source region and largescale circulation in the northwestern tropical Pacific Ocean,both of which are related to the Pacific Decadal Oscillation.The underlying processes at work are further confirmed through conducting the subsurface salinity budget analysis.Besides,short-term processes are also at work through nonlinear interactions,especially after 2000.     

Relict glacial landscape in the Sierra Baguales Mountain Range(50°-51° S): evidence of glaciation dynamics and types in the eastern foothills of the southern Patagonian Andes

The glacial morphology of southern South American presents invaluable evidence to reconstruct former glacier behaviour and its relation to climate and environmental changes. However, there are still spatial and temporal gaps in the reconstruction of the Holocene Patagonian glacial landscape. Here we present the first geomorphological record for the Sierra Baguales Mountain Range(SBMR), forming the eastern foothills of the Southern Patagonian Andes 200 km from the Pacific coast. This area is topographically isolated from the Southern Patagonian Ice Field(SPIF), and is affected by the Westerly Winds. The study area shows evidence of ice sheet and alpine glaciations related to Andean uplift,which caused a marked climatic contrast between its western and eastern flanks since the Last Glacial Maximum(LGM). The regional rock mass strength and precipitation gradient acted as a controlling factor in the glacial cirque distribution and sizes, as well as in the development of glaciation types. We report new radiocarbon dates associated with warm/dry to cold/wet climatic changes during the middle Holocene, when former small alpine glaciers were located in the uppermost section of the SBMR basins, and eventually converged to form a small ice field or a composite valley glacier at lower elevations.This can be explained by an estimated regional temperature drop of 3.8°C±0.8°C, based on a 585±26m Equilibrium Line Altitude(ELA) descent, inferred by geomorphological evidence and the Accumulation Area Ratio(AAR), in addition to a free-air adiabatic lapse rate. Subsequently, the glaciers receded due to climatic factors including a rise in temperature, as well as non-climatic factors, mainly the glacier bedrock topography.     

The Origin and Preservation of Suspended Barites near the 90°E Ridge in the Northeastern Indian Ocean

Suspended particulate barite crystals were detected in the water columns at four different stations near the 90°E ridge in the Indian Ocean. Four distinct morphological types of marine barites were distinguished: euhedral-subhedral crystals, oval or round crystals, rhombic crystals, and irregular crystals. The barite crystals in the study area are typically fine, with a dominant size of 1 – 3μm. The vertical distribution of barites is significantly affected by the formation and sedimentation pro...     

Simulation of double cold cores of the 35°N section in the YellowSea with a wave-tide-circulation coupled model

Based on the MASNUM wave-tide-circulation coupled numerical model, the temperature structure along 35°N in the Yellow Sea was simulated and compared with the observations. One of the notable features of the temperature structure along 35°N section is the double cold cores phenomena during spring and summer. The double cold cores refer to the two cold water centers located near 122°E and 125°E from the depth of 30m to bottom. The formation, maintenance and disappearance of the double cold cores are discussed. At least two reasons make the temperature in the center (near 123°E) of the section higher than that near the west and east shores in winter. One reason is that the water there is deeper than the west and east sides so its heat content is higher. The other is invasion of the warm water brought by the Yellow Sea Warm Current (YSWC) during winter. This temperature pattern of the lower layer (from 30m to bottom) is maintained through spring and summer when the upper layer (0 to 30m) is heated and s     

Geochemical features of sulfides from the Deyin-1 hydrothermal field at the southern Mid-Atlantic Ridge near 15°S

In this study, geochemical compositions of elements in sulfide samples collected from the Deyin-1 hydrothermal field near the 15°S southern Mid-Atlantic Ridge (SMAR) were analyzed by the X-ray fluorescence spectrometry (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) to examine the enrichment regulations of ore-forming elements and hydrothermal mineralization. These sulfide precipitates can be classified macroscopically into three types: Fe-rich sulfide, Fe-Cu-rich sulfide and Fe-Zn-rich sulfide, and are characterized by the enrichment of base metal elements along with a sequence of Fe>Zn>Cu. Compared with sulfides from other hydrothermal fields on MAR, Zn concentrations of sulfides in the research area are significantly high, while Cu concentrations are relatively low. For all major, trace or rare-earth elements (REE), their concentrations and related characteristic parameters exhibit significant variations (up to one or two orders of magnitude), which indicates the sulfides from different hydrothermal vents or even a same station were formed at different stages of hydrothermal mineralization, and suggests the variations of chemical compositions of the hydrothermal fluid with respect to time. The hydrothermal temperatures of sulfides precipitation decreased gradually from station TVG10 (st.TVG10) to st.TVG12, and to st.TVG11, indicating that the precipitation of hydrothermal sulfides is subjected to conditions changed from high temperature to low temperature, and that the hydrothermal activity of study area was at the late stage of a general trend of evolution from strong to weak. The abnormally low concentrations of REE in sulfides and their similar chondrite-normalized REE patterns show that REEs in all sulfides were derived from a same source, but underwent different processes of migration or enrichment, or sulfides were formed at different stages of hydrothermal mineralization. The sulfides collected from the active hydrothermal vent were mainly attributed to precipitating directly from the hydrothermal fluid, while those collected from the extinct hydrothermal chimney might have already been altered by the seawater. Generally, ore-forming elements in the sulfides can be divided into three groups: Fe-based element group, Cu-based element group and Zn-based element group. The first group includes Fe, Mn, Cr, Mo, Sn, Rb and bio-enriching elements, such as P and Si, reflecting the similar characteristics to Fe in the study area. And the second group contains Cu, W, Co, Se, Te and Bi, suggesting the similar behavior with Cu. Moreover, the third group includes Zn, Hf, Hg, Cd, Ta, Ga, Pb, As, Ag, Ni and Sb, which indicates the geochemical characteristics of most dispersed trace elements controlled by Zn-bearing minerals to some extent.     

资源360°论语

“规划规划,不如领导一句话。”——投资7000多万元,号称“国内最高人物铜像”被拆……日前,“广西柳州柳宗元人物铜像被拆”事件在网络上持续发酵,也引发了2014中国城市规划年会与会嘉宾关注和热议。9月13—15日在海口召开的中国城市规划年会上,多名城市规划专家指出,城市当政者与规划者要谨防长官意志导致政绩规划、随意规划,同时还需谨防利益驱使导致商业规划、过度规划。     

资源360°动态

国土资源部办公厅下发通知开展打非治违专项行动 国土资源部办公厅近日下发《关于配合开展“六打六治”打非治违专项行动的通知》,就国土资源主管部门配合开展“六打六治。专项行动有关事项作出部署。“六打六治。就是对6类非法违法、违规违章行为,进行集中打击和整治。其中包括：打击矿山企业无证开采、超越批准的矿区范围采矿行为,整治图纸造假、图实不符问题：打击破坏损害油气管道行为,整治管道周边乱建乱挖乱钻问题。     

资源360°舆情

官员腐败 受贿 贪污 贵州 8月17日 今年5月起,赛昭市开展为期一年的打击党员干部参与违法“种房”的“三禁止”专项行动。目前,已查处党员干部参与、支持纵容和收受贿赂等有关违法“种房”的案件51件55人,使违法“种房”势头得到遏制。     

西南印度洋中脊48.6°~51.7°E沉积物地球化学特征

为了深入了解西南印度洋中脊调查区表层沉积物的物质来源和沉积环境,对大洋第30航次在该区域获取的21个表层沉积物样品进行了物相鉴定和主量元素、微量元素及稀土元素含量测试,分析结果显示,样品可分为Si质沉积物和Ca质沉积物两类,其中Si质沉积物富含Si、Mg、Fe、Al,稀土元素含量特征、轻重稀土元素分馏特征,以及稀土元素的北美页岩归一化曲线均表明沉积物保留了N-MORB的特征,主要为基性岩、超基性岩的风化产物;而Ca质沉积物富Ca、LOI、Sr,稀土元素以及微量元素之间的分配均指示沉积物物源为生源主导;所有站位均显示了两类沉积物不同程度的混杂,表明物质来源具有一定的多样性,调查区总体为稳定的偏氧化环境。      

Holocene temperature records from the East China sea mud area southwest of the Cheju Island reconstructed by the U 37 K′ and TEX86 paleothermometers

As an important marginal sea under the influences of both the Changjiang River and the Kuroshio, the East China Sea (ECS) environment is sensitive to both continental and oceanic forcing. Paleoenvironmental records are essential for understanding the long-term environmental evolution of the ECS and adjacent areas. However, paleo-temperature records from the ECS shelf are currently very limited. In this study, the U ₃₇ ^K′ and TEX₈₆ paleothermometers were used to reconstruct surface and subsurface temperature changes of the mud area southwest of the Cheju Island (Site F10B) in the ECS during the Holocene. The results indicate that temperature changes of F10B during the early Holocene (11.6–6.2 kyr) are associated with global climate change. During the period of 6.2–2.5 kyr, the similar variability trends of smoothing average of ΔT (the difference between surface and subsurface temperature) of Site F10B and the strength of the Kuroshio suggest that the Kuroshio influence on the site started around 6.2 kyr when the Kuroshio entered the Yellow Sea and continued to 2.5 kyr. During the late Holocene (2.5–1.45 kyr), apparent decreases of U ₃₇ ^K′ sea surface temperature (SST) and ΔT imply that the direct influence of the Kuroshio was reduced while cold eddy induced by the Kuroshio gradually controlled hydrological conditions of this region around 2.5 kyr.     

北太平洋150°E-165 °E海域柔鱼重心渔场的年间变动

利用空间距离和灰色关联度分析方法对1995～2001年间北太平洋150°E—165°E柔鱼作业渔场的重心分布进行比较研究,1995～1997年8～10月份作业渔场的重心与1998～2001年存在着较大的差异,前者基本上在150°E—153°30E的42°30′N以南海域,而后者位于155°E-161°E的42°45′N以北海域。聚类结果表明,8月份作业渔场重心分为三类:1998～2001年为一类,1996～1997年为一类,而1995年为一类。9月份产量重心与作业渔船重心的聚类结果则有所不同,产量重心的聚类结果为四类,即1999～2001年为一类,1997、1996年为一类,1998年和1995年各为一类;而作业渔船重心的聚类结果则分为三类,即1999～2001年为一类,1995～1997年为一类,1998年为一类;10月份作业渔场重心分为三类;1998、2001和1999年为一类,1995～1997年为一类,2000年为一类。年间的渔场变化可能是由海洋环境条件所引起。灰色关联分析表明,产量重心与作业渔船重心存在一定的差异。8～10月份作业渔场重心的总体变化趋势为向东北偏东移动。     

VARIABILITY OF THERMOHALINE STRUCTURE AT 4°S,156°E DURING TOGA COARE IOP

The thermohaline structure at 4 °S, 156 °E was analyzed based on CTD data acquired during theTOGA COARE Intensive Observing Period(IOP) from November,1992 to February,1993. The ocean re-sponses during two Madden-Julian Oscillation(MJO)events were preliminarily studied based onmeteorological field observation.The main water masses at the observation point were Tropical SurfaceWater, Southern Subtropical Lower Water and Southern Intermediate Water from surface downward. Therewas good correlation of sea surface temperature with the wind field,and of the surface salinity with windspeed and rainfalls. Both of the two surface variables were also modulated by upwelling caused by west-erly winds at the observation point. The isohaline layer was not always shallower than the isothermal lay-er in this observation and could be considered as the lower limit of the diurnal variation of theisothermal layers in most cases. The existence of large variations of the maximum salinity core is sug-gested to be related to t     

How Unique is ′China Model′: A Review of Theoretical Perspectives on China′s Urbanization in Anglophone Literature

As a major aspect of the ′China Model′, urbanization in China is being heatedly discussed in the Anglophone literature in the last two decades. By considering China′s urbanization as a ′testing ground′ of ′western′ theories, these studies are important for the understanding of China′s ongoing urban restructuring and exchanging knowledge with ′western′ insights. Based on a survey of existing studies, this paper identifies various endogenous and exogenous concepts and explanations of China′s urbanization. It is suggested that China′s urbanization is mainly driven by a combination of political decentralization and neoliberalization with various forms of social stratification and mobility. However, it is argued that the distinctness of the ′China Model′, which is usually used to support the legitimacy of studies of China′s urbanization, has led to many controversial arguments and diminished the due contributions of Chinese scholars in the knowledge production of China′s urbanization. To consolidate the legitimacy of studies on China′s urbanization and enhance the roles of Chinese scholars, we suggest future studies to pay more attentions to the fundamental theories with looser constraints and ′true questions′ on China′s urbanization.     

北纬30°--优质茶叶产区带

北纬30°是地球上一条奇特的地质带,也是一条优质茶叶产区带。西湖龙井、君山银针、蒙顶甘露等10大传统名茶中有9个就产生在这一纬度上,中国两大优质茶区正好穿它而过。产生这一优质茶叶生产带的原因:一是地球板块碰撞产生的奇异地貌和土壤母质;二是北纬30°的宜茶气候条件;三是生物多样性带来良好的生态环境。这一带生产的茶叶不仅品质良好,而且安全可靠,有着十分光明的发展前景。     

ISSUES ON CHINA′S ENERGY SECURITY

Energysupplyisadeterminantfactor to the developmentand the prosperity of a modern society. China is one ofthe largest energy consumers andproducersin the world,and energy supply and its security in the country aregreat issues concerned not onlybytheChina …