塔里木盆地沉积剥蚀过程与油气关系

塔里木盆地典型井的周期分析表明,塔里木盆地在其地质历史时期100Ma左右的周期是很明显的,自寒武纪以来共经历了4个完整的周期,每一完整周期都由正相位和负相位两个半周期所组成。而第三纪为第5个周期的正相位阶段。该周期控制了盆地内的沉积与剥蚀的过程及成藏旋回。对沉积与剥蚀过程的控制作用表现在周期波正相位和负相位分别对应于沉积期和剥蚀期,这在地质年代序列中表现为沉积与间断的互为消长的演化进程。对食油气系统的控制作用表现在:第1个周期波构成以早古生代地层为主体的含油气系统,第2个周期波至第4个周期波构成以晚古生代至中生代地层为主体的含油气系统,第5个周期的正相位阶段构成以第三纪地层为主体的含油气系统。     

沉积波动过程分析在地层层序分析中的应用--以塔里木盆地为例

沉积波动过程是地壳波状运动的具体表现,它是各种天文因素、地质因素共同作用的结果,沉积波动过程的时空演化控制着地层层序的时空展布特点。在介绍沉积波动过程分析概念、技术思路、工作方法的基础上,利用沉积波动曲线在剖面上的预测功能及对沉积－剥蚀过程起止时间、不整合的研究成果,分析了塔里木盆地震旦系至第四系各主要构造层的地层展布特征,并对其形成过程及成因进行了分析,在理论和方法研究方面,试图将沉积波动特征的研究与层序地层学的研究结合起来,提出了地层格架－沉积波动特征连井对比图的概念和编制方法,该类图件能直观地反映多期不整合的存在及不整合间断的时间,并能直观地反映各层序的时空分布,而且能够解释地层格架的形成过程,进而进行成因分析,是沉积波动过程分析方法与层序地层学结合的一种具体、有益的偿试。     

用窗口法估计不连续面的连通率

基于不连续面与窗口交切的必需而充分的条件,推导了不连续面迹长、间断长和不连续面连通率的估算公式,通过实例验证了该公式的正确性。     

Interplay of tectonics and neogene post-collisional magmatism in the intracarpathian region

Distribution of the Neogene calc-alkaline magmatism of the Carpathian arc is directly related in space and time to the kinematics of the two major terranes of the Intracarpathian area (Alcapa, Tisia-Getia) along the south-eastern border of the European plate. In the West Carpathians and adjacent areas, the volcanic activity occurred between 20–11 Ma, with large volumes of both acidic and intermediate rocks, generally distributed randomly, sometimes transversally to the orogenic belt and as rare small occurrences along the Flysch belt. In the East Carpathians, the volcanic rocks are distributed along the northern margin of the Zemplin block, the north–easternmost part of the Alcapa and eastward along the front of the Getic block, at the contact with European plate. Between Tokaj-Slanské-Vihorlat up to northern Cãlimani Mountains, the magmatism occurred between 14–9 Ma, and along the Cãlimani-Harghita chain between 9–0.2 Ma. The calc-alkaline magmatic rocks of the Apuseni Mountains are located in the interior of the Tisia block and occurred between 14–9 Ma. The generation of the calc-alkaline magmatism is considered here as the result of complex interplay between plate roll-back and lithospheric detachment tectonic processes and the break-off of the subducted plate, mostly in a post-collisional setting. (1) The magmatites of the Western Carpathians and the Pannonian basin were generated in direct relation to subduction roll-back processes, over the downgoing slab, during the period of lateral extrusion and back-arc extension. In this area, characterized by maximum crustal shortening, we can infer further delamination processes to explain the generation of magmas. (2) The magmatic rocks from the northern sector of the East Carpathians (Tokaj-Slanské-Vihorlat up to the Northern Cãlimani Mountains), resulted after subduction roll-back processes and an almost simultaneous break-off of the descending plate all along the arc segment during main clockwise rotation of the Intracarpathian terranes. (3) In the eastern sector of the East Carpathians (Cãlimani up to Harghita Mountains), the magmatic rocks were generated through partial melting of the subducted slab followed by gradual break-off of the subducted plate along strike (north to south). (4) The Apuseni Mts. magmatic activity resulted in transtensional tectonic regime by decompressional melting of lithospheric mantle, during the translation and rotation of Tisia-Getia block.     

化学地层划分在区域地质调查中的应用

利用岩层中的地球化学差异对地层进行划分是地层学的研究方法之一。本文利用在区调工作中获得的较为系统的岩石光谱半定量全分析数据,采用有序样品最优分割法和对分移动窗口法,对新疆温都哈拉一带的古生代地层进行了化学地层划分,并与野外根据宏观岩性特征划分的岩石地层单位进行了比较。     

航空重力测量中FIR低通滤波器的比较

航空重力测量数据中含有大量的噪声,需要采用FIR低通滤波器来提取实际的重力异常信息。结合一组实测的航空重力测量数据,讨论FIR低通数字滤波器截止频率和滤波器长度的确定方法,研究了无效数据的删除方法;通过比较不同窗函数设计的滤波器的数据处理性能,得出了在航空重力测量数据处理中,汉宁窗和海明窗设计FIR低通数字滤波器可以满足重力场信息提取的要求。     

谱分解技术在预测煤层岩浆岩侵入区的应用

岩浆岩的侵入问题一直严重影响着煤矿的安全和高效生产,如何准确地划分出岩浆岩侵入区范围是急需解决的关键问题之一。通过对正演模型数据和实际数据的谱分解分析,发现正常煤层与岩浆岩侵入煤层间存在着明显的频谱差异。正常煤层反射波在其主频对应的谱分解切片上的能量较强,而岩浆岩侵入煤层反射波在同一谱分解切片上的能量较弱。对于实际煤层数据来说,通过钻井标定,即可以定量、准确地划分出岩浆岩侵入区的范围。以大屯煤电公司徐庄煤矿为例,对7煤层谱分解沿层切片与振幅沿层切片进行了对比解释,结果证实谱分解技术对预测煤层岩浆侵入范围是切实可行的。     

深海极端环境模拟装置设计

为了满足深海极端环境科学研究的需求,设计了深海极端环境模拟装置。对系统结构以及工作原理进行分析,介绍了培养釜、温度控制子系统和压力控制子系统。重点针对当前模拟装置压力控制精度不高的问题,设计了高精度压力传感器,并提出一种迭代自学习PID压力控制算法,实现系统压力自动检测和连续控制,同时带有观察窗的培养釜结构可以实现微生物状况实时观测。实验结果表明,该系统能够实现深海极端环境参量高精度模拟,可以为深海极端环境科学研究提供很好的平台。     

Petrology,geochemistry and geochronology of the magmatic suite from the Jianzha Complex,central China: Petrogenesis and geodynamic implications

The intermediate–mafic–ultramafic rocks in the Jianzha Complex (JZC) at the northern margin of the West Qinling Orogenic Belt have been interpreted to be a part of an ophiolite suite. In this study, we present new geochronological, petrological, geochemical and Sr–Nd–Hf isotopic data and provide a different interpretation. The JZC is composed of dunite, wehrlite, olivine clinopyroxenite, olivine gabbro, gabbro, and pyroxene diorite. The suite shows characteristics of Alaskan-type complexes, including (1) the low CaO concentrations in olivine; (2) evidence of crystal accumulation; (3) high calcic composition of clinopyroxene; and (4) negative correlation between FeO^tot and Cr₂O₃ of spinels. Hornblende and phlogopite are ubiquitous in the wehrlites, but minor orthopyroxene is also present. Hornblende and biotite are abundant late crystallized phases in the gabbros and diorites. The two pyroxene-bearing diorite samples from JZC yield zircon U–Pb ages of 245.7 ± 1.3 Ma and 241.8 ± 1.3 Ma. The mafic and ultramafic rocks display slightly enriched LREE patterns. The wehrlites display moderate to weak negative Eu anomalies (0.74–0.94), whereas the olivine gabbros and gabbros have pronounced positive Eu anomalies. Diorites show slight LREE enrichment, with (La/Yb)_N ratios ranging from 4.42 to 7.79, and moderate to weak negative Eu anomalies (Eu/Eu¹ = 0.64–0.86). The mafic and ultramafic rocks from this suite are characterized by negative Nb–Ta–Zr anomalies as well as positive Pb anomalies. Diorites show pronounced negative Ba, Nb–Ta and Ti spikes, and typical Th–U, K and Pb peaks. Combined with petrographic observations and chemical variations, we suggest that the magmatism was dominantly controlled by fractional crystallization and crystal accumulation, with limited crustal contamination. The arc-affinity signature and weekly negative to moderately positive ε_Nd(t) values (−2.3 to 1.2) suggest that these rocks may have been generated by partial melting of the juvenile sub-continental lithospheric mantle that was metasomatized previously by slab-derived fluids. The lithologies in the JZC are related in space and time and originated from a common parental magma. Geochemical modeling suggests that their primitive parental magma had a basaltic composition. The ultramafic rocks were generated through olivine accumulation, and variable degrees of fractional crystallization with minor crustal contamination produced the diorites. The data presented here suggest that the subduction in West Qinling did not cease before the early stage of the Middle Triassic (∼242 Ma), a back-arc developed in the northern part of West Qinling during this period, and the JZC formed within the incipient back-arc.     

庐枞盆地泥河铁矿床成矿岩体三维形态学分析及找矿指标研究

泥河铁矿床位于长江中下游成矿带内庐枞盆地的西北部,属玢岩型铁矿床,前人对该矿床的基础地质研究已有一定成果,积累了大量的数据资料,表明泥河铁矿床的形成与辉石闪长玢岩顶面形态关系密切。本文选择泥河铁矿床闪长玢岩为研究对象,以钻孔资料为依据,采用离散光滑插值法建立成矿岩体的精细三维模型,重现了闪长玢岩体的形态特征,将三维模型离散化后提取岩体顶面并通过三维形态分析方法进行数值分析,提取了岩体表面的隆起、凹陷形态,并与已知矿体进行对比,验证了该矿床成矿岩体隆起形态与矿体位置的对应关系。本文通过多次实验确定最佳表达的滑动窗口尺寸和与成矿岩体形态有关的找矿指标,结果证明利用10×10个单元的滑动窗口可以识别80%以上矿体。本文对三维成矿预测中三维空间分析方法进行探索,证明成矿岩体三维形态分析方法的有效性,这一方法可直接应用于与泥河铁矿床类似的玢岩型铁矿床三维成矿预测中。