东准噶尔造山带非史密斯地层类型划分及等级体制建立

在研究东准噶尔造带类型及发展历史的基础上建立区域构造格架、组合形式 ,划分出构造 -地层体类、构造 -岩层体类、构造 -混杂体类的非史密斯地层。按照所划分类型的各自特征 ,能够满足造山带 1∶ 2 5万填图精度的要求 ,对全部无序或局部无序的地 (岩 )层建立“岩群、岩组、岩段、岩层”等级体制 ;对那些总体有序、局部无序或总体无序、局部有序的地层 ,能通过各种手段恢复原始层序 ,服从史密斯地层层序律的 ,按“群、组、段、层”建立等级体制     

Zircon U-Pb ages and Hf isotopic characteristics of the Dehe biotite monzonitic gneiss pluton in the North Qinling orogen and their geological significance

The Dehe granitic pluton intruded the Xiahe Group which is in the core complex of the North Qinling Orogenic Belt(NQOB).It shows gneissic bedding and possesses typical S-type granite minerals such as muscovite and garnet.LA-ICP-MS U-Pb isotopic dating of the Dehe granite yielded a weighted average age of 925±23 Ma which represents the emplacement age of the pluton.Most of the εHf(t) values are negative,and the two-stage model ages are consistent with the age of the Qinling Group.The isotope data show that the Dehe granite was formed in the following geological setting:in the syn-collision setting of the NQOB in the Neoproterozoic,crustal thickening induced partial melting of materials derived from the Qinling complex,and then the maga upwelled and intruded into the Xiahe Group.The formation of the Dehe S-type granite implied the occurrence of a convergent event in the QOB during the Neoproterozoic.     

Tourmaline from the Archean G.R.Halli gold deposit,Chitradurga greenstone belt,Dharwar craton （India）： Implications for the gold metallogeny

Tourmaline occurs as a minor but important mineral in the alteration zc,ne of the Archean orogenic gold deposit of Guddadarangavanahalli （G.R.Halli） in the Chitradurga greenst~ne belt of the western Dharwar craton, southern India. It occurs in the distal alteration halo of the G.R.Halli golcl deposit as （a） clusters of very fine grained aggregates which form a minor constituent in the natrix of the altered metabasalt （AMB tourmaline） and （b） in quartz-carbonate veins （vein tourmaline）. ~[＇he vein tourmaline, based upon the association of specific carbonate minerals, is further grouped as （i） albite-tourmaline-ankerite-quartz veins （vein-1 tourmaline） and （ii） albite-tourmaline-calcite-quartz veins （vein-2 tourmaline）. Both the AMB tourmaline and the vein tourmalines （vein-I and vein-2） belong to the alkali group and are clas- sified under schorl-dravite series. Tourmalines occurring in the veins are zoned while the AMB tour- malines are unzoned. Mineral chemistry and discrimination diagrams 1eveal that cores and rims of the vein tourmalines are distinctly different. Core composition of the ve：n tourmalines is similar to the composition of the AMB tourmaline. The formation of the AMB tourmaline and cores of the vein tour- malines are proposed to be related to the regional D1 deformational event associated with the emplacement of the adjoining ca. 2.61 Ga Chitradurga granite whilst rims of the vein tourmalines vis-a- vis gold mineralization is spatially linked to the juvenile magmatic accretion （2.56-2.50 Ga） east of the studied area in the western part of the eastern Dharwar craton.     

重力负载对库车褶皱冲断带盐构造的影响

库车褶皱冲断带新生代沉积了库姆格列木群和吉迪克组2套盐岩,发育复杂的盐构造,重力负载对其形成和发育具有重要影响。利用水压头分析方法,分析了重力对库车褶皱冲断带盐构造的影响。重力负载对盐岩流动的影响包括重力扩张和沉积负载2种,重力扩张作用由盐岩受自身重力控制,而沉积负载作用由上覆沉积物重力作用控制。水压头分析表明在盐岩高程大的地方,其沉积负载往往更小。在重力扩张和沉积负载共同作用下,库车褶皱冲断带不会发生由盐岩自身重力而形成的重力扩张,重力负载对库车褶皱冲断带盐岩的影响仅表现为沉积差异负载作用。     

内蒙古北山造山带时空结构与古亚洲洋演化

内蒙古北山造山带自北向南发育红石山－百合山、月牙山－洗肠井和帐房山－玉石山3条蛇绿构造混杂岩带。其中北部的2条蛇绿岩带揭示了北山造山带两阶段演化的历史：月牙山－洗肠井蛇绿混杂岩带洋壳形成于530~520 Ma,沿该带多处保存较完好的蛇绿岩洋壳残块（洋壳结构具向北变新特征）,与北侧的早古生代公婆泉岩浆弧（由南向北岛弧成熟度变高）共同指示了北山洋向北俯冲消减的过程,即490 Ma初始俯冲,450~440 Ma为俯冲峰期,430~420 Ma为同碰撞阶段,400 Ma的双峰式岩浆岩组合指示了北山洋的消亡和后造山伸展的过程;红石山－百合山蛇绿混杂岩带是发育在雀儿山－圆包山岛弧基础上的SSZ型蛇绿岩,弧后开裂洋壳的形成与南侧最早发育的岛弧岩浆作用年龄接近（340~320 Ma）,310~290 Ma俯冲峰期造成南侧白山岩浆弧大量的岩浆活动,早二叠世末期（275 Ma）的辉长岩和花岗岩侵位及早—中二叠世双堡塘组下部的角度不整合均反映了红石山洋盆的闭合。前人所划"石板井－小黄山蛇绿岩带"实为一条早古生代发育的深大断裂,沿带发育中基性侵入体及少量超基性岩,后期（志留纪末）叠加有较强的韧性剪切变形。中生代以来的走滑作用和逆冲推覆构造改造了古生代的构造格架,使红石山-百合山蛇绿混杂岩带向北左行切错了十余千米,北山南部的中—新元古界推覆至下古生界之上。对内蒙古北山造山带时空结构的厘定,有助于中亚造山带造山作用过程的理解及其对古生代地壳增生的深入研究,也对银额盆地晚古生代新层系油气资源勘查起到基础支撑。     

Complex vein systems as a data source in tectonics: An example from the Ugab Valley,NW Namibia

Neoproterozoic metaturbidites in the Lower Ugab Domain, Namibia, contain a complex network of four sets of quartz-calcite veins, overprinted by km-scale folds associated with four regional foliations. The veins formed by fluid overpressure predating the main deformation. Deformation structures developed at the junction of two mobile belts during the assembly of Gondwana, the NS Kaoko Belt, and the EW trending Damara Belt. Km-scale NS trending folds were initiated during EW constriction in the Kaoko Belt, while their further development and all subsequent events are related to constriction in the EW-Damara Belt, with coeval sinistral strike slip in the Kaoko Belt. Deformation of the veins, and development of four orthogonal foliations are due to gradual changes in the bulk tectonic framework rather than separate orogenic events. The veins are deformed in a complex manner allowing a full 3D reconstruction of regional sequence of events. The local complex tectonics could be reconstructed because of the perfect local exposure and the multitude of veins: it illustrates the potential complexity of tectonic events and structural evolution in apparently simple slate belts.     

Garnet-biotite diffusion mechanisms in complex high-grade orogenic belts: Understanding and constraining petrological cooling rates in granulites from Ribeira Fold Belt (SE Brazil)

Cooling rates based on the retrograde diffusion of Fe²⁺ and Mg between garnet and biotite inclusions commonly show two contrasting scenarios: a) narrow closure temperature range with apparent absence of retrograde diffusion; or b) high result dispersion due to compositional variations in garnet and biotite. Cooling rates from migmatites, felsic and mafic granulites from Ribeira Fold Belt (SE Brazil) also show these two scenarios. Although the former can be explained by very fast cooling, the latter is often the result of open-system behaviour caused by deformation. Retrogressive cooling during the exhumation of granulite-facies rocks is often processed by thrusting and shearing which may cause plastic deformation, fractures and cracks in the garnet megablasts, allowing chemical diffusion outside the garnet megablast – biotite inclusion system.However, a careful use of garnets and biotites with large Fe/Mg variation and software that reduces result dispersion provides a good correlation between closure temperatures and the size of biotite inclusions which are mostly due to diffusion and compositional readjustment to thermal evolution during retrogression.Results show that felsic and mafic granulites have low cooling rates (1–2 °C/Ma) at higher temperatures and high cooling rates (∼100 °C/Ma) at lower temperatures, suggesting a two-step cooling/exhumation process, whereas migmatites show a small decrease in cooling rates during cooling (from 2.0 to 0.5 °C/Ma). These results agree with previously obtained thermochronological data, which indicates that this method is a valid tool to obtain meaningful petrological cooling rates in complex high-grade orogenic belts, such as the Ribeira Fold Belt.     

Metamorphic and cooling history of the Shimanto accretionary complex,Kyushu, Southwest Japan: Implications for the timing of out‐of‐sequence thrusting

Illite crystallinity, K–Ar dating of illite, and fission‐track dating of zircon are analyzed in the hanging wall (Sampodake unit) and footwall (Mikado unit) of a seismogenic out‐of‐sequence thrust (Nobeoka thrust) within the Shimanto accretionary complex of central Kyushu, southwest Japan. The obtained metamorphic temperatures, and timing of metamorphism and cooling, reveal the tectono‐metamorphic evolution of the complex, and related development of the Nobeoka thrust. Illite crystallinity data indicate that the Late Cretaceous Sampodake unit was metamorphosed at temperatures of around 300 to 310°C, while the Middle Eocene Mikado unit was metamorphosed at 260 to 300°C. Illite K–Ar ages and zircon fission‐track ages constrain the timing of metamorphism of the Sampodake unit to the early Middle Eocene (46 to 50 Ma, mean = 48 Ma). Metamorphism of the Mikado unit occurred no earlier than 40 Ma, which is the youngest depositional age of the unit. The Nobeoka thrust is inferred to have been active during about 40 to 48 Ma, as the Sampodake unit started its post metamorphic cooling after 48 Ma and was thrust over the Mikado unit at about 40 Ma along the Nobeoka thrust. These results indicate that the Nobeoka thrust was active for more than 10 million years.     

STUDY ON GIS FOR YIELD ESTIMATION BY REMOTE SENSING IN JILIN MAIZE BELT

ＳＴＵＤＹ　ＯＮ　ＧＩＳ　ＦＯＲ　ＹＩＥＬＤ　ＥＳＴＩＭＡＴＩＯＮ　ＢＹ　ＲＥＭＯＴＥ　ＳＥＮＳＩＮＧ　ＩＮ　ＪＩＬＩＮ　ＭＡＩＺＥ　ＢＥＬＴＳＴＵＤＹＯＮＧＩＳＦＯＲＹＩＥＬＤＥＳＴＩＭＡＴＩＯＮＢＹＲＥＭＯＴＥＳＥＮＳＩＮＧＩＮＪＩＬＩＮＭＡＩＺ...     

“一带一路”成员国居民健康状况的时空统计分析

健康是影响不同国家和地区发展的关键因素,全面了解“一带一路”成员国的居民健康状况,是探讨“一带一路”成员国之间健康医疗合作的重要基础。本文选择了4个代表性的健康状况指标（出生期望寿命、总生育率、过早非传染性疾病死亡率和结核病发病率）,利用Moran's I指数、Getis-Ord G指数对“一带一路”135个成员国的健康状况进行时空统计,分析了健康状况的空间相关性和空间分布模式,研究了健康状况的时空格局。研究发现：① 2000—2016年“一带一路”大部分成员国的各项健康状况指标均朝着改善和优化方向发展;健康状况指标均呈现显著的正空间自相关性;② 总体而言,在“一带一路”成员国中,欧洲国家的居民健康状况最好;南北美洲和大洋洲国家的居民健康状况良好;亚洲国家的居民健康状况总体良好,但东南亚部分国家的结核病发病率较高;非洲国家的居民健康状况虽有明显改善,但仍处于较低状态。因此,“一带一路”成员国应进一步加强健康医疗合作,共同推动健康丝绸之路的发展。