准噶尔盆地结构及其圈闭类型

准噶尔盆地是复合叠加前陆盆地 ,其原型分别形成于板块俯冲、碰撞、造山带后期复活、拗拉槽回返和板内皱陷作用有关的大地构造环境。其古生代盆地的形成与相邻的阿尔泰山和东、西准噶尔山、天山及博格达山的造山作用相关。中新生代盆地的形成和改造与其南部特提斯域板块俯冲碰撞造山引起的盆地相邻造山带的复活有关。相邻造山带时空上不均一的造山作用对盆地的影响不同 ,形成了盆地独特的结构。各坳陷均由与其形成有关的造山带前缘冲断带、陡坡带、山前凹陷、缓坡带和前隆及前缘皱陷等构成 ,前隆之间的叠加构成了盆地的大型隆起 ,皱陷叠加构成了盆地的中央坳陷。不同类型的圈闭在坳陷中有规律地分布着     

Cobalt‐Bearing Grunerite in the Metamorphosed Banded Iron Formation in Orissa,India

Banded iron formation (BIF) comprising high grade iron ore are exposed in Gorumahisani‐Sulaipat‐Badampahar belt in the east of North Orissa Craton, India. The ores are multiply deformed and metamorphosed to amphibolite facies. The mineral assemblage in the BIF comprises grunerite, magnetite/martite/goethite and quartz. Relict carbonate phases are sometimes noticed within thick iron mesobands. Grunerite crystals exhibit needles to fibrous lamellae and platy form or often sheaf‐like aggregates in linear and radial arrangement. Accicular grunerite also occur within intergranular space of magnetite/martite. Grunerite needles/accicules show higher reflectivity in chert mesoband and matching reflectance with that of adjacent magnetite/martite in iron mesoband. Some grunerite lamellae sinter into micron size magnetite platelets. This grunerite has high ferrous oxide and cobalt oxide content but is low in Mg‐ and Mn‐oxide compared to the ones, reported from BIFs, of Western Australia, Nigeria, France, USA and Quebec. The protolith of this BIF is considered to be carbonate containing sediments, with high concentrations of Fe and Si but lower contents of cobalt and chromium ± Mg, Mn and Ni. During submarine weathering quartz, sheet silicate (greenalite) and Fe‐Co‐Cr (Mg‐Mn‐Ni)‐carbonate solid solution were formed. At the outset of the regional metamorphic episode grunerite, euhedral magnetite and recrystalized quartz were developed. Magnetite was grown at the expense of carbonate and later martitized under post‐metamorphic conditions. With the increasing grade of metamorphism greenalite transformed to grunerite.     

库车前陆褶皱-冲断带前缘盐构造分段差异变形特征

库车前陆褶皱-冲断带前缘秋里塔格构造带发育大量盐构造,其类型丰富多样。根据野外露头、钻井和地震资料识别出的盐构造样式主要有盐推覆、盐枕、盐墙、盐焊接、鱼尾构造、盐撤凹陷、突发构造、断层传播褶皱、断层转折褶皱和三角带构造等。秋里塔格构造带盐构造变形表现出明显的分段差异变形特征,其中西段却勒地区以古隆起(盐下)—盐枕(盐层)—逆冲推覆构造(盐上)为主;中段西秋地区以构造斜坡(盐下)—盐墙(盐层)—断层传播褶皱、向斜(盐上)为主;东段东秋地区则以断层转折褶皱(盐下)—盐推覆(盐层)—断层传播褶皱(盐上)为主。造成这种盐构造分段差异变形的主要控制因素包括基底断裂、含盐层系、构造转换带和变形空间等方面的差异性,其中基底构造和含盐层系的差异性起主导作用。     

Deep root of a continent-continent collision belt: Evidence from the Chinese Continental Scientific Drilling (CCSD) deep borehole in the Sulu ultrahigh-pressure (HP-UHP) metamorphic terrane, China

The Chinese Continental Scientific Drilling (CCSD) deep borehole, which reached a depth of 5158 m in the Sulu ultrahigh-pressure (UHP) metamorphic terrane, provides a new window into the deep root of a continent-continent collision belt, and the tectonic processes by which supracrustal material is recycled into the mantle by subduction and then uplifted to the surface. Major research themes of the CCSD project were to: (1) determine the three-dimensional composition, structure and geophysical character of the deep root of this orogenic belt; (2) investigate the nature and timing of the UHP metamorphism; (3) investigate the processes of crust-mantle interaction involved in the formation and exhumation of the UHP rocks; (4) study the process of fluid circulation and mineralization during subduction and exhumation; (5) study the rheological properties of the various rocks during subduction and exhumation; (6) develop and refine dynamic models for deep subduction and exhumation of crustal rocks, and (7) establish a long-term, natural laboratory for the study of present-day crustal dynamics (e.g., stress, strain, fluid activity). The CCSD has developed precise oriented profiles of the main borehole in terms of lithology, geochemistry, oxygen isotopes, zircon SHRIMP U-Pb ages, ⁴⁰Ar-³⁹Ar ages, deformation, rheology, mineralization, physical properties of the rocks, petrophysical logs, seismic reflections and underground fluids. The present paper summarizes the integrated research results of this project, especially the new findings concerning the deep root of a continent-continent collision.     

点苍山-哀牢山变质杂岩带变沉积岩的变质演化

点苍山-哀牢山变质杂岩带位于青藏高原东南缘大理-元江-元阳-河口一带,出露规模达数百千米,是扬子板块和印支陆块之间的一条重要构造带.该变质杂岩带主要由各类正片麻岩、副片麻岩、大理岩所组成,夹有斜长角闪岩、石榴辉石岩和超镁铁质岩石的透镜体或团块.其中,变沉积岩如含夕线石和蓝晶石的片麻岩类岩石保存了多阶段的矿物组合及异常复杂的矿物相转变关系.详细的岩相学、成因矿物学以及矿物相转变关系分析表明,变沉积岩系经历了早期进变质阶段(M1)、峰期角闪-麻粒岩相变质阶段(M2)、峰后近等温减压(脱水熔融)阶段(M3)以及晚期退变质阶段(M4)的变质演化.其中,M1阶段的稳定矿物组合为石榴石+斜长石+白云母+石英+十字石±蓝晶石±黑云母±钾长石,M2阶段的稳定矿物组合为石榴石+黑云母+蓝晶石/夕线石+斜长石+石英、石榴石+黑云母+斜长石+石英±钾长石±夕线石,M3阶段的共生矿物组合为石榴石+黑云母+夕线石+斜长石+石英,M4阶段的矿物组合为黑云母+白云母+斜长石+石英±钾长石±石榴石等.通过传统GB-GASP温压计和二云母温度计的估算结果,配合P-T视剖面定量计算,确定早期进变质阶段(M1)的温压条件为T=560 ～ 590℃,P=5.5 ～6.3kb,峰期角闪-麻粒岩相阶段(M2)的温压条件为T=720～ 760℃、P=8.0～9.3kb,峰后近等温减压阶段(M3)的温度压力条件为T=640～760℃,P=5.0～7.3kb,晚期退变阶段(M4)的温压条件为T=521～648℃,P=4.0～5.0kb.上述研究结果表明,点苍山-哀牢山变沉积岩记录了典型碰撞造山带型式的顺时针P-T演化轨迹,表明点苍山-哀牢山变质杂岩带的形成与印度板块和欧亚板块之间的俯冲-碰撞存在密切的成因关系.     

冀东青龙河太古宙花岗岩绿岩带地质特征

青龙河花岗岩 绿岩带形成于新太古代晚期 ,形成环境为古岛弧环境 ,绿岩地体由双山子群、朱杖子群组成。区内褶皱构造、韧性剪切变形带及脆性断裂带十分发育。绿岩地体的形成时间为 2 6 50～ 2 750Ma。花岗质岩石即“TTG”岩系安子岭片麻岩套 ,由四个深成侵入体组成 ,其中柳各庄片麻岩单元直接侵入双山子群鲁杖子组。柳各庄片麻岩多件锆石U Pb一致线年龄数据在 2 510～ 2 550Ma之间。     

地质灾害井间地震层析成像研究

地质灾害体如岩溶、陷落柱、软弱层等的井间地震层析成像属于复杂模型或大扰动异常体的非线性成像，该文首次将小波多尺度思想纺入到蟛间层析成像，建立了小波多尺度井间地震层析成像方法，很好地解决了非线性成像的难题，大大地提高了图像的质量和分辨率，数值模型试验和实际工程应用证实了该方法的实用性和良好效果。     

大别造山带毛屋岩体的解体及古地幔性质的厘定

根据详细的地球化学 (特别是稀土元素地球化学 )的研究资料 ,提出大别造山带毛屋岩体应该解体。毛屋岩体不是由多幕式镁铁 超镁铁质层状堆晶作用形成的一套岩石系列 ,而是由橄榄岩类、含石榴石方辉岩类、榴辉岩类和绿辉石岩类组成的一个混杂岩体。其中含石榴石方辉岩类与绿辉石岩类之间存在成因上的联系 ,含石榴石方辉岩类的原岩是本区原始地幔经约36 %的部分熔融后剩下的残余 ,而绿辉石岩的原岩是由该熔融体结晶的产物。根据含石榴石方辉岩与绿辉石岩之间的成分制约关系 ,对该区古地幔的稀土元素组成和地幔性质进行了反演 ,结果表明 ,该区原始地幔稀土元素成分与球粒陨石中的相似 ,为轻稀土略亏损的平坦型组成模式 ;该区原始地幔矿物成分为橄榄石 (72 8% )、单斜辉石 (12 4% )和石榴石 (14 8% ) ,属含单辉石榴橄榄岩的地幔。     

Prograde amphiboles in hematite-bearing basic and quartz schists in the Sanbagawa belt, central Shikoku: relationship between metamorphic field gradient and P-T paths of individual rocks

The prograde amphibole that coexists with chlorite, epidote, muscovite, albite, quartz and hematite in Sanbagawa schists was examined to investigate the relationship between the prograde P-T paths of individual rocks and the metamorphic field gradient in the Sanbagawa metamorphic belt, central Shikoku. The amphibole changes from actinolite, through ferri-winchite and crossite, to barroisite and hornblende with increasing grade along the metamorphic field gradient. However, the sequence of prograde amphibole compositions in each sample varies in different mineral zones. The general scheme can be summarized as: magnesioriebeckite-riebeckite crossite in the upper chlorite zone of lower-grade rocks; crossite or glaucophane barroisite in the garnet zone of medium-grade rocks; and actinolite or winchite barroisite hornblende in the albite-biotite zone of higher-grade rocks. Changes of amphibole composition indicate that the prograde P-T path recorded in the higher-grade rocks was situated on the higher-temperature side of that of the lower-grade rocks and on the lower-pressure side of the metamorphic field gradient. The systematic change of P-T paths implies an increasing d P /d T during continuous subduction. These features can be interpreted as documenting prograde metamorphism within a young subduction zone that has a non-steady-state geotherm.     

利用地质成果优化3010皮带上山设计

3010皮带上 山 建成 后将 担 负着 范各 庄 矿三 水平 、四 水平 的 煤炭 运输 任 务,服务 年 限要 求 至 少 30a。 此 皮 带上山 位于 岩 溶陷 落柱 较 发育 的井 口 区域 ,范 各庄 矿 发现 的 12个 陷落 柱 全部 位于 此 区域 。由 于 陷落 柱直 接 导通 下部 奥 灰水 ,一 旦揭 露 将有 淹没 整 个矿 井的 危 险。为 保 证矿 井安 全 ,在 工程 施工 前 ,利用 地 质手 段对 设 计区 域进 行 了探 查,发现皮 带上 山 的中 上部 发 育有 岩溶 陷 落柱 ,两 次对 设 计进 行了 修 改,为 施 工提 供了 安 全保 障。