重力方法在祁连山地区构造特征与岩体解释中的应用

依据地质、航磁等资料,结合实测岩石物性资料,以1∶250 000重力资料为基础对祁连山地区(张掖、刚察地区)进行综合研究。研究地质构造与地球物理特征,划分了大地构造单元,探讨了隐伏与半隐伏岩体分布。该区域经多年的重力工作,勘探面积已近3万多km²,根据重力资料研究布格重力场特征并进行分区; 对地质构造单元重新划分,对主要断裂进行探讨; 圈定隐伏与半隐伏岩体,推断其空间展布特征,并对其解释。结果表明: 祁连山地区地壳密度结构横向分区、纵向分层明显,布格重力异常场的分区特征与地质构造分区特征基本一致。结合2.5D重力剖面反演印证了新的推测结果,为综合地质、地球物理找矿提供参考。     

Petrogenesis of plio-quaternary intra-plate continental alkaline lavas from the İskenderun Gulf (Southern Turkey): Evidence for metasomatized lithospheric mantle

The Quaternary alkaline volcanic field of Southern Turkey is characterized by intra-continental plate-type magmatic products, exposed to the north of the ?skenderun Gulf along a NE-SW trending East Anatolian Fault, to the west of its intersection with the N–S trending Dead Sea Fault zone. The ?skenderun Gulf alkaline rocks are mostly silica-undersaturated with normative nepheline and olivine and are mostly classified as basanites and alkaline basalts with their low-silica contents ranging between 43 and 48?wt.% SiO₂. They display Ocean Island Basalt (OIB)–type trace element patterns characterized by enrichments in large-ion-lithophile elements (LILE) and light rare earth element (LREE), and have (La/Yb)_N?=?8.8–17.7 and (Hf/Sm)_N?=?0.9–1.6 similar to those of basaltic rocks found in intraplate suites. The basanitic rocks have limited variations Sr-Nd isotopic ratios (⁸⁷Sr/⁸⁶Sr?=?0.70307–0.70324, ¹⁴³Nd/¹⁴⁴Nd?=?0.512918–0.521947), whereas the alkali basalts display more evolved Sr-Nd isotopic ratios (⁸⁷Sr/⁸⁶Sr?=?0.70346-0.70365, ¹⁴³Nd/¹⁴⁴Nd?=?0.512887–0.521896). The ?skenderun Gulf alkaline rocks also display limited Pb isotopic variations with ²⁰⁶Pb/²⁰⁴Pb?=?18.75–19.09 ²⁰⁷Pb/²⁰⁴Pb?=?15.61–15.66 and²⁰⁸Pb/²⁰⁴Pb?=?38.65–39.02, indicating that they originated from an enriched lithospheric mantle source. Calculated fractionation vectors indicate that clinopyroxene and olivine are the main fractionating mineral phases. Similarly, based on Sr-Nd isotopic ratios, the assimilation and fractional crystallization (AFC) modeling shows that the alkali basalts were affected by AFC processes (r?=?0.2) and were slightly contaminated by the upper crustal material.The high TiO₂ contents, enrichments in Ba and Nb, and depletions in Rb can likely be explained by the existence of amphibole in the mantle source, which might, in turn, indicate that the source mantle has been affected by metasomatic processes. The modeling based on relative abundances of trace elements suggests involvement of amphibole-bearing peridotite as the source material. ?skenderun Gulf alkaline rocks can thus be interpreted as the products of variable extent of mixing between melts from both amphibole-bearing peridotite and dry peridotite.     

压力对辉长岩矿物反应和部分熔融影响的实验研究

本文在高温高压条件下,开展了辉长岩矿物反应与部分熔融实验,利用偏光显微镜与扫描电镜对实验样品微观结构观察,研究实验中的新生矿物与熔体的分布;通过电子探针分析熔体成分特征。实验结果表明,在低压(300MPa)条件下,静压和塑性变形实验样品中,单斜辉石以固体反应方式生成橄榄石,在高压(1300MPa)塑性实验中所有实验样品都没有发现新生矿物颗粒,这与相图中低压条件下斜长石与橄榄石稳定共存,而高压下斜长石-辉石稳定共存相吻合。高压塑性变形条件下,单斜辉石和黑云母首先发生部分熔融,随着温度增高,斜长石逐渐参与熔融,熔体呈薄膜状分布在矿物颗粒边界,熔体成分依赖于参与熔融的矿物成分,表明出现的熔体为非平衡熔融结果。     

藏南喜马拉雅造山带造山型马扎拉Au-Sb矿床和沙拉岗Sb矿床流体包裹体He-Ar同位素组成:对成矿流体来源的制约

马扎拉Au-Sb矿床和沙拉岗Sb矿床是藏南金锑成矿带中典型的造山型矿床。马扎拉Au-Sb矿床中矿体以含金辉锑矿石英脉的形式产于下中侏罗统陆热组地层中,主要组成矿物有自然金、辉锑矿、石英和碳酸盐矿物;沙拉岗Sb矿床中矿体主要以辉锑矿石英脉的形式产于下白垩统多久组地层和辉长岩体中,主要组成矿物为辉锑矿、辰砂、锑华、石英和少量碳酸盐矿物。在两个矿床的矿脉石英和辉锑矿中均发现有三类原生和假次生包裹体:水溶液包裹体、CO2-水溶液包裹体和有机包裹体。流体包裹体显微测温结果显示:马扎拉Au-Sb矿床的成矿温度为160～280℃,沙拉岗Sb矿床的成矿温度为140～240℃。He-Ar同位素分析显示马扎拉Au-Sb矿辉锑矿石英脉矿石中辉锑矿和石英以及赋矿地层中沉积层状硫化物中黄铁矿的流体包裹体均具有低的3He/4He比值,分别为0. 01382～0. 05642Ra和0. 03353～0. 08744Ra,40Ar/36Ar比值具有比较大的变化范围,分别为346. 8～4770. 1和349. 4～2689. 1;沙拉岗Sb矿床中辉锑矿样品的3He/4He比值为0. 02385～0. 11488Ra,40Ar/36Ar比值变化小,为300. 6～537. 5。与藏南Au-Sb成矿带中造山型Au矿床成矿流体中含一定量的幔源挥发份相对比,马扎拉AuSb矿床和沙拉岗Sb矿床成矿流体中均无幔源流体的参与,马扎拉Au-Sb矿床成矿流体为壳源变质流体与改造型饱和大气水形成的混合流体;沙拉岗Sb矿床成矿流体以改造型饱和大气水为主,并有壳源变质流体的加入。     

班公湖-怒江缝合带东段丁青地幔橄榄岩成因:来自钻孔ZK02地幔橄榄岩矿物学及地球化学特征约束

丁青蛇绿岩位于班公湖-怒江缝合带东段,是该缝合带出露面积最大的蛇绿岩。为查明岩体成因,在丁青东岩体中实施了一口165.19m的钻孔。除最顶部有约0.5m厚的第四系残坡积物外,其余均为地幔橄榄岩。结合显微镜鉴定将岩心划分出17个岩性单元层,岩性主要以方辉橄榄岩为主,夹少量纯橄岩和含铬铁矿纯橄岩。地幔橄榄岩中橄榄石的Fo变化于88.79~93.73,铬尖晶石的Cr^#变化于44.33~81.66,揭示丁青地幔橄榄岩可能经历过约20%~40%的中高度部分熔融作用;全岩地球化学分析表明其具有富镁（MgO=45.98%~49.45%）、贫铝（Al₂O₃=0.19%~1.37%）和贫钙（CaO=0.28%~0.70%）的特点,属于熔融程度较高的地幔残余物质。岩石具有明显不同于阿尔卑斯蛇绿岩的轻稀土元素富集特征,指示区内地幔橄榄岩先经历了较强程度的部分熔融,后经历了俯冲消减过程中的流体交代。利用地幔橄榄岩中的铬尖晶石成分计算母熔体Al₂O₃含量对应的FeO/MgO值,与不同构造环境原始岩浆成分相比较,发现丁青地幔橄榄岩母熔体大多处于玻安岩中。纯橄岩氧逸度估算FMQ=-3.05~-0.71,方辉橄榄岩氧逸度FMQ=-3.89~+1.47,显示丁青地幔橄榄岩有俯冲作用的参与。通过丁青钻孔岩心的研究,提出丁青东岩体可能形成于俯冲带之上的弧前环境这一观点。     

Cenozoic Crustally-derived Carbonate-rich Magmatic Rocks in West Junggar,North Xinjiang,Western China: Geochronology,Geochemistry and Tectonic Implications

The carbonate-rich magmatic rocks of West Junggar are distributed in the Baijiantan and Darbut ophiolitic mélanges in the forms of extrusive rocks overlying the mélanges and dykes, either along the margins of the mélange or cross-cutting components of mélanges. Chilled margin and flow structures are present. A SHRIMP zircon U-Pb age of 39.7 ± 1.3 Ma indicates that these carbonate-rich rocks in West Junggar were formed during the Eocene. They have low concentrations in REEs, Th, U, Nb, Ta and are characterized by extremely low εN d(t), high(87 Sr/86 Sr)i ratios, relatively high δ18 OV-SMOW values and high δ13 CV-PDB values, which is similar with most sedimentary carbonates. Furthermore, no contemporaneous mantle-derived silicate rocks have yet been found in West Junggar. The carbonate-rich rocks in West Junggar are thus distinct from mantle-derived carbonatites and are interpreted to result from melting of the Carboniferous sedimentary carbonates at crustal levels, these rocks therefore being referred to as 'crustal carbonatites'. The Eocene crustal carbonatites in West Junggar and other Cenozoic magmatic rocks in North Xinjiang are generally situated along regional strike-slip faults or fault intersections. Therefore, we propose that the reactivation of the Darbut and Baijiantan crustal-scale strike-slip fault zones(ophiolitic mélanges), due to the far-field effects of the Indian-Eurasian collision, enables decompression melting of the underlying continental lithospheric mantle. These resulting melts ascended to the lower crust through the strike-slip faults, causing partial melting of the Carboniferous carbonaceous sediments. The crustal carbonatites in West Junggar provide a new piece of evidence for Cenozoic magmatism in North Xinjiang and are also significant for the investigation of tectono-magmatic relations in North Xinjiang and the Central Asian Orogenic Belt.     

基于偏最小二乘回归的区域换式风速预报订正技术研究

利用偏最小二乘回归技术,将预报产品作为自变量,相应的自动气象站观测资料作为因变量,对2013-2016年冬季浙江省中尺度区域模式预报近地面风速进行订正和评估。所选956站中多数站点风速订正后有所改善,通过定量分析可知浙江西部地区整体改善效果最好,其中效果明显站点占91.7%;中部地区改善效果明显站点占86.5%;东部沿海地区改善效果略差,明显改善的站点占67%。各地级市整体表现均不错,除舟山地区为49.9%外,其他地区风速改善比例均超过50%。选取2017年1月20日浙江东北地区沿海大风过程分析发现订正后的风速与观测风速更为接近,在定海大岛站点(靠里)中表现尤为明显,订正后的结果具有显著参考价值。     

核心筒部分悬挂结构抗震分析的简化力学模型

提出了核心筒部分悬挂结构体系,在已有该体系振动台试验基础上,建立了该体系的抗震分析简化力学模型及其理论公式。按小震、中震和大震3种不同的地震作用情况,分析了该结构体系力学模型和动力方程的差异。利用有限元分析程序SAP2000,对这种结构体系进行了小震和大震作用下的结构地震反应分析,计算结果与试验结果吻合较好。     

河北阜平地区太古宙变质深成岩与金矿的关系初探

区内变质深成岩由阜平岩群变质表壳岩经深部重熔作用形成,典型特征是低钾富钠,具有TTG岩石特点.经对变质深成岩成矿元素的研究表明:①Au元素丰度值很高(平均2.10×10-6),远远高于世界中性-中酸性侵入岩及地壳中Au元素的丰度值;②Au元素浓集克拉克值(488.37)远远大于1,呈非常强的富集状态;③Au元素在变质深成岩中的变异系数(0.65)几乎是区内变质表壳岩中Au元素的2倍,有利于Au元素的聚集成矿.故变质深成岩应是成矿物质的主要提供者.     

提高机采水平的配套技术及应用

随着濮城油田的持续性高速开发,油田综合含水逐渐上升,油水井井况进一步恶化,作为油田生产主体的机械采油井躺井频繁、管杆泵使用寿命缩短。近几年中原油田采油二厂濮城油田年平均躺井数达560井次之多,导致机械采油井维护费用增加,管杆泵投入增大,严重制约着油田的生产和经营。通过加缓蚀剂在油管内壁形成保护油膜,起到润滑作用;应用特殊抽油杆防腐止磨;应用尼龙扶正器对抽油杆体扶正,避免了钢体与钢体的硬磨;应用旋转井口通过地面人力转动改变油管与抽油杆的偏磨面;配合合理生产参数;各种配套技术的合理应用,使濮城油田躺井减少,避免了频繁作业,增加长寿井,管杆泵投入节约了19.3%。