若尔盖铀矿区复杂易斜地层定向分支钻孔施工技术

在陡斜矿体上施工分支钻孔,不但节约钻探工作量,减少钻机搬迁、修路次数,对环境保护和提高地质找矿效果也有重要意义。主要介绍了用LZ型连续造斜器在易斜地层施工定向分支钻孔的技术和工艺。     

Petrogenesis of the Bondla layered mafic-ultramafic complex,Usgaon, Goa

The Bondla mafic-ultramafic complex is a layered intrusion that consists predominantly of peridotites and gabbronorites. A chromitite-pyroxenite-troctolite horizon serves as a marker to subdivide the intrusion into two zones. The Lower Zone displays gravity stratified layers of chromite that alternate with those of olivine, which up-section are followed by olivine+pyroxene-chromite cumulates. The Upper Zone comprises gabbroic rocks that exhibit uniform layering. On the basis of modal and cryptic variation exhibited by the minerals this zone can be subdivided in to several lithohorizons starting from the troctolites at the base to gabbronorites and leucogabbros at the top. The junction between the two zones is marked by the distinct reversal in cryptic variation exhibited by the chromites and pyroxenes. The peridotite chromites contain higher Al₂O₃ and lower Cr₂O₃ than those from the chromitite above. Similarly clinopyroxenes from pyroxenite and troctolites are more magnesian that those from the peridotites stratigraphically below them. The complex in general is characterized by a gabbroic mineral assemblage in which both Ca-rich and Capoor pyroxenes coexist and displays a Fe-enrichment trend providing evidence of evolution from a contaminated tholeiitic magma. The rocks are characterized by low-TiO₂; Ni, Cr and V, show negative correlation with Zr whereas the large ion lithophile elements (LILE) are positively correlated and the Nb/La ratio varies from 0.4–0.6. These characteristics are consistent with a low-TiO₂ sub-alkaline tholeiitic magma that may have been modified by fractional crystallization and successive injections of more primitive melts in the magma chamber. The complex evolved in a periodically replenished magma chamber that consisted of two separate but interconnected sub-chambers.     

Large-scale Tazhong Ordovician Reef-flat Oil-Gas Field in the Tarim Basin of China

The Tazhong reef-flat oil-gas field is the first large-scale Ordovician organic reef type oil-gas field found in China. Its organic reefs were developed in the early Late Ordovician Lianglitag Formation, and are the first large reefs of the coral-stromatoporoid hermatypic community found in China. The organic reefs and platform-margin grain banks constitute a reef-flat complex, mainly consisting of biolithites and grainstones. The biolithites can be classified into the framestone, bafflestone, bindstone etc. The main body of the complex lies around the wells from Tazhong-24 to Tazhong-82, trending northwest, with the thickness from 100 to 300 m, length about 220 km and width 5-10 km. It is a reef-flat lithologic hydrocarbon reservoir, with a very complex hydrocarbon distribution: being a gas condensate reservoir as a whole with local oil reservoirs. The hydrocarbon distribution is controlled by the reef complex, generally located in the upper 100-200 m part of the complex, and largely in a banded shape along the complex. On the profile, the reservoir shows a stratified feature, with an altitude difference of almost 2200 m from southeast to northwest. The petroleum accumulation is controlled by karst reservoir beds and the northeast strike-slip fault belt. The total geologic reserves had reached 297.667 Mt by 2007.     

广西栗木锡矿区深孔钻进工艺研究

通过对栗木锡矿复杂地层的分析,采用绳索取芯技术,多级套管根管技术,优质泥浆护壁堵漏等钻进工艺,并对孔内事故的预防与处理提出了一系列措施,成功解决了该区深孔钻进的难题,取得了很好效果。     

基于谱运算的复相关函数法在干涉复图像配准中的应用

复图像配准是干涉SAR处理中的关键步骤之一,要求配准精度达到0.1个像元的水平,而控制点的精确定位是复图像配准中的核心环节.尽管前人提出采用复相关系数法、信噪比法、平均扰动函数法等算法,但他们都是基于滑动窗口的算法,运算效率低.在分析前人算法的基础上,引入基于谱运算的复相关函数算法实现控制点的亚像元级精确定位,分析比较了算法的计算复杂度.应用该算法对我国某地区ERS-2的SLC数据进行了实验,生成了干涉图像,并进行了相干性分析,证明了该算法的可行性和稳健性.实验研究证明即使在主从图像时间间隔较大、相干性差的情况下,应用该算法也能获得干涉条纹图.     

关于发展洋板块地质学的思考

为揭示造山带物质组成和结构构造,发展洋板块地质学,阐明大陆形成演化过程和动力来源,应用板块构造理论和地质学方法,对造山带俯冲增生杂岩带、蛇绿岩带等大洋岩石圈板块地质建造、结构构造进行系统研究,寻找俯冲带岛弧前弧火成岩组合;研究洋板块初始俯冲过程中,从前弧玄武岩到玻安岩、高镁安山岩,再到弧拉斑玄武岩和钙碱性熔岩的岩浆作用分阶段递进演变历史,以揭示洋盆向大陆转化的原始弧性质和前弧火成岩组合及洋陆转换过程,为建立和发展洋板块地质学奠定科学基础.     

南羌塘增生过程的中-晚三叠世岩浆记录:藏北玛依岗日-角木日地区基性岩墙

古特提斯洋向北俯冲形成增生杂岩,它们向南增生构成了南羌塘增生地体,且增生期内发育的岩浆岩可以用来研究南羌塘的增生过程。在南羌塘增生杂岩带内,由北向南,发育有玛依岗日(MG)辉长岩墙、角木日(JM)辉长辉绿岩墙。锆石U-Pb测年结果显示,两者分别形成于237. 1±2. 3Ma和230. 7±1. 8Ma,为南羌塘增生期内岩浆岩。它们的岩石地球化学特征均介于OIB与E-MORB之间,富集Ti、Nb,以及LREE和LILE。Nd-Pb同位素结果显示两者均起源于富集地幔源区。Sm/YbLa/Yb图解显示,两者均起源于尖晶石-石榴石二辉橄榄岩源区,相对于JM辉长辉绿岩MG辉长岩部分熔融程度较高。两者Mg#和Ni、Cr特征表明,MG辉长岩分异程度高于JM辉长辉绿岩。Th/Nb-La/Nb图解显示,相对于JM辉长辉绿岩MG辉长岩经历了一定程度的地壳混染。综合研究认为,MG辉长岩和JM辉长辉绿岩为古特提斯洋壳俯冲过程中软流圈上涌的两次岩浆活动的产物,并受俯冲洋壳和地幔楔影响。MG辉长岩和JM辉长辉绿岩记录了南羌塘的增生过程,它们为相关研究提供了岩浆岩证据。     

PM2.5降尘对大鼠的急性肺损伤及复合维生素B的干预作用研究

为探讨复合维生素B(叶酸、B_6和B_(12))能否抑制PM_(2.5)对大鼠的急性肺损伤作用,本研究将56只SD大鼠随机分成对照组、不同剂量(0. 4、2. 0、10. 0 mg/m L) PM_(2.5)染毒组和相应的复合维生素B干预组(0. 02 mg/m L叶酸、1 mg/m L维生素B6、0. 002 5 mg/m L维生素B12),取肺组织进行HE染色观察组织病理学形态变化并进行病理学评分;收集支气管肺泡灌洗液(BALF)测定总蛋白(TP)、乳酸脱氢酶(LDH)、碱性磷酸酶(AKP)、酸性磷酸酶(ACP)、丙二醛(MDA)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的含量。结果显示,PM_(2.5)染毒能对大鼠肺组织造成不同程度的病理性损伤,复合维生素B能减缓此损伤;与对照组相比,低、中、高剂量的PM_(2.5)染毒大鼠可引起BALF中LDH、AKP、ACP、TP和MDA含量显著升高(P 0. 05),而SOD和CAT活性显著降低(P 0. 05),且TP和MDA含量随染毒剂量的增加而升高(P 0. 05),CAT活性随染毒剂量的增加而降低; 3个染毒剂量的复合维生素B干预组LDH、TP和MDA含量显著降低(P 0. 05),而SOD和CAT活性显著升高(P 0. 05); PM_(2.5)低、高剂量+复合维生素B组BALF中ACP含量显著降低(P 0. 05); PM_(2.5)中剂量+复合维生素B组BALF中ACP含量无显著改变;仅有PM_(2.5)低剂量+复合维生素B组AKP含量降低(P 0. 05),其余干预组AKP含量无显著变化。因此认为,PM_(2.5)降尘能打破机体的氧化-抗氧化平衡,造成大鼠急性肺损伤,而复合维生素B能减缓此损伤,对机体起到保护作用。     

东非鲁武马盆地渐新统富砂深水朵体复合体特征及影响因素

近年来的天然气发现证实地处东非被动大陆边缘的鲁武马盆地渐新统朵体复合体具有巨大的资源潜力和良好的勘探前景。朵体复合体具有粗粒、巨厚、宽厚比低、向单侧偏转的特征,明显异于常规席状砂。利用油气勘探过程中获得的岩芯、测井及地震信息,分析深水沉积朵体复合体不同级别的岩性特征、电性响应和地震反射特征;借助地震剖面解剖和沿层相干切片识别了不同级别的朵体复合体内部组成,分析朵体复合体的沉积过程,同时探讨了影响朵体复合体沉积的主要因素。研究表明,鲁武马盆地渐新统朵体复合体具有"无根"的外部形态及复杂的地震内部反射结构,可以分为朵体复合体、朵体、朵体单元及层-层组等四个级别。朵体复合体形成于块体搬运沉积之后和水道复合体沉积之前,为下降期体系域晚期的产物,推测海平面变化速率影响朵体复合体储层垂向分布,基准面下降速率越大,单层砂岩厚度越大,两者呈现出正相关的特征。朵体复合体沉积经历了多期朵体的沉积过程:早期填平补齐的限制性沉积,中期多期侧向迁移的非限制性沉积,以及末期边部高弯曲迁移的富泥水道沉积;从补给水道口向朵体复合体远端,伴随浊流强度逐渐衰减,携带粗粒物质的能力逐渐降低,近端及主体部位厚度大,砂泥比高,边缘及远端沉积厚度减薄,砂泥比降低;主体部位的砂泥比是补给水道口及较远端的2～3倍;陆架形态、地形坡度及与基准面之间的关系影响朵体复合体的沉积位置、外部形态及迁移方式:"窄陆架、陡陆坡"促使粗粒、富砂的朵体复合体近源堆积;地形坡度与基准面一致时浊流在陆坡区的"过路不留",导致朵体复合体形成"无根"的外部形态;沿陆坡走向的坡度变化导致朵体的侧向迁移。     

Structure and tectonic evolution of the Late Jurassic–Early Cretaceous Wandashan accretionary complex,NE China

The Late Jurassic–Early Cretaceous Wandashan accretionary complex (AC) in NE China is a key region for constraining the subduction and accretion of the Palaeo-Pacific Ocean; however, the protoliths and structure of the region remain poorly understood, resulting in debates regarding crustal growth mechanisms and subduction-related accretionary processes in Northeast China. In this contribution, we integrate detailed field observations, ocean plate stratigraphy (OPS) reconstruction, and associated geological data to determine the structure and tectonic evolution of the Wandashan AC. The Wandashan AC formed through the progressive incorporation of OPS units along an oceanic trench. The observed OPS comprises, in ascending order, Permian basalt and limestone, Middle Triassic–Early Jurassic chert, Middle Jurassic siliceous shale and mudstone, and Late Jurassic–Early Cretaceous turbidite. Numerous NNE–SSW-striking thrust faults have segmented the OPS into a series of bedding-parallel tectonic slices that were successively thrust over the Jiamusi massif along a basal thrust (the Yuejinshan Fault), producing a large-scale imbricate thrust system. The Wandashan AC underwent oceanward accretion via multiple deformational processes. The OPS units were detached and rearranged along or within a decollement through offscraping, underplating, thrusting, and duplexing. The units were then emplaced over the Jiamusi massif along the basal thrust. The timing of accretion and thrusting is constrained to the latest Middle Jurassic to earliest Early Cretaceous (ca. 167–131 Ma). Reconstructed accretion-related structural lines within the Wandashan AC trend dominantly NE–SW, close to the direction of Jurassic extension at the eastern Asian continental margin. Large-scale left-lateral strike-slip movement on the Dunmi Fault during the late Early Cretaceous resulted in the folding of structural lines within the Wandashan AC, producing their present-day westward-convex orientation.