Geochemical characteristics of crude oils from Well Zheng-1 in the Junggar Basin, Xinjiang, China

Well Zheng-1 is located in the combined area of the central uplift and the north Tianshan piedmont depression in the Junggar Basin. Two oil-bearing beds are recognized at 4788–4797 m of the Lower Cretaceous Tugulu Formation (K1tg) and 4808.5–4812.5 m of the Lower Jurassic Sangonghe Formation (J1s). The geochemical characteristics of family composition, carbon isotopic composition, saturated hydrocarbons, sterane and terpane biomarkers and carotane of two crude oils are described in this paper. The results show that the geochemical characteristics of the two crude oils are basically similar to each other, indicating they were all derived mainly from the high mature, brine, algae-rich lake facies sediments. Oil-source correlation revealed that crude oils of the two beds were derived mainly from the source rocks of Permian and mixed by the oil derived from the source rocks of Jurassic and Triassic. This is consistent with the geological background with several sets of source rocks in the area studied.     

Chronology of an oyster reef on the coast of Bohai Bay, China: Constraints from optical dating using different luminescence signals from fine quartz and polymineral fine grains of coastal sediments

Fossil oyster reefs are indicators of past sea levels, and their formation is usually dated by means of radiocarbon. However, radiocarbon dating of the shells from coastal areas may be complicated by the varying sources of carbon. Here we applied optical dating methods to date the samples from above and below a fossil oyster bed in a section on the coast of Bohai Bay, China. The optical ages of the sediments were used to constrain the oyster bed. Single-aliquot regenerative-dose procedures using the OSL signal from fine grain quartz, the IRSL and post-IR OSL signals from polymineral fine grains were employed to determine equivalent dose (D_e). The behaviors of the different luminescence signals from quartz and polymineral grains during D_e measurements were examined. The results showed that the quartz OSL signal is more reliable than the polymineral IRSL and post-IR OSL signals with respect to dating for these coastal samples. The optical ages indicated that the oyster reef formed between ca. 6.2 and 5.0 ka.     

对门源盆地"红层"形成时代的新认识

门源盆地位于青藏高原东北缘北祁连山腹地,为狭长的新生代走滑拉分山间宽谷盆地。其中充填一厚约407~960 m、干旱气候条件下的河湖相沉积"红层",长期以来各项研究工作均未能于其中采获任何生物化石。因此,尽管各家均认同其属"第三纪"无疑,但仍对其确切时代存在着较大的争论,而对其时代的确定有助于正确认识门源盆地形成时的构造背景,具有较为重要的意义。通过区域地层对比、"红层"形成气候条件与南侧西宁盆地及北邻酒泉—张掖盆地古气候环境所作的对比,深入探讨认为其时代属中中新世,并初步分析了门源盆地形成的新构造运动大陆动力学机制背景。     

对江南-雪峰带构造属性的讨论

讨论了江南-雪峰山“隆起带”的性质问题,它既不是造山带的“厚皮构造”,也不属于沉积盖层褶皱的“薄皮构造”,而是“过渡型的基底拆离式”的构造。其发生机制是印支—早燕山运动期间由SE向NW(同时派生由S向N、由E向W)的基底拆离和推覆,成为控制整个扬子板块海相中古生界盆地改造变形的动力来源和主导因素,也控制了海相油气的形成与聚集。     

覆膜态Fe（OH）3在厌氧条件下生物降解苯和甲苯的初探

天然条件下氯代烃的污染经常会与石油烃的污染共存,对于这种混合污染羽的治理,第一步采用粒状铁还原氯代烃,后续利用微生物和第一步产生的副产物生物降解石油烃。苯系物是石油烃中毒性较大、存留时间较长的污染物,本文利用批实验的方法研究了厌氧条件下用Fe(OH)3覆膜于石英砂表面的Fe(Ⅲ)作为电子受体降解苯和甲苯。结果表明,Fe(Ⅲ)作为电子受体时苯和甲苯能够发生厌氧生物降解,经过驯化后苯和甲苯的降解速度明显加快。降解实验表明甲苯的降解速度比苯的降解速度快,苯降解的半衰期是4.02d,甲苯降解的半衰期是3.81d。     

川西北平武地区南一里花岗闪长岩锆石U-Pb定年及其地质意义

川西北平武地区的碧口地块中出露较多的印支期岩浆侵入岩类,但缺乏精确的年代学资料.笔者运用阴极发光技术,对碧口地块西南缘的南一里化岗闪长岩中的锆石进行了细致的内部结构分析,并在此基础上利用LA-ICP-MS锆石U-Pb原位定年技术进行了同位素年龄测定.结果表明,花岗闪长岩中锆石Th/U比值较高,阴极发光图像显示锆石内部发育振荡环带,具岩浆成因特点;南一里花岗闪长岩的结晶年龄为223.1±2.6 Ma(MSWD=1.4),表明其形成时代为晚三叠世早期、南一里花岗闪长岩侵入时代晚于勉略构造带的主碰撞期,侵位于后碰撞环境,或者至少是由同碰撞到后碰撞的转折阶段.     

Cold Air Activities in July 2004 and Its Impact on Intense Rainfalls over Southwest China

The severe rainfall events in the mid-summer of July 2004 and the roles of cold air in the forma- tion of heavy precipitation are investigated by using daily observational precipitation data of China and NCEP/NCAR reanalysis.The results show that the severe rainfalls in Southwest China are closely related to the cold air activities from the mid-high latitudes,and the events take place under the cooperative effects of mid-high latitude circulation and low latitude synoptic regimes.It is the merging of a cold vortex over mid-latitudes with the northward landing typhoon and eastward Southwest China Vortex,as well as the abrupt transformation from a transversal trough into an upright one that causes three large alterations of mid-high atmospheric circulation respectively in the early and middle ten days of this month.Then,the amplitude of long waves soon magnifies,leading to the unusual intrusion of cold air to low-latitude areas in the mid-summer.Meanwhile,the warm and humid southwest summer monsoon is quite active.The strong interactions of cold air and summer monsoon over Southwest China result in the large-scale convective rain- falls on the southern side of cold air. With regard to the activities of cold air,it can influence rainfalls in three prominent ways.Firstly,the incursion of upper-level cold air is often accompanied by partial southerly upper-level jet.The ascending branch of the corresponding secondary circulation,which is on the left front side of the jet center,provides the favorite dynamic upward motion for the rainfalls.Secondly,the southward movement of cold air contributes to the establishment of atmospheric baroclinic structure,which would lead to baroclinic disturbances.The atmospheric disturbances associated with the intrusion of cold air can destroy the potential instability strat- ification,release the convective available potential energy(CAPE)and finally cause convective activities.In addition,the advection processes of dry and cold air at the upper level along with the advection of humid and warm air at the lower level are rather significant for the reestablishment of potential instability in the precipitation area,which is one of the crucial factors contributing to persistent rainfalls.     

加密自动气象站蓄电池使用及维护

1引言加密自动气象站投入运行以来,由于蓄电池原因引起的故障占了较大比例,为保证加密自动气象站正常运行,就如何对蓄电池进行正确的使用和维护进行论述。     

基于地性线的不规则三角网优化构建算法

提出了利用自动增加特征点消除平三角形的方法，并通过重构等高线验证了构网算法的实用性和有效性。实验表明，本文算法能很好地消除不合理的平三角形，优化三角网结构。     

测绘档案管理现代化的若干问题分析

在测绘科技快速发展的今天,建立现代化的测绘科技档案势在必行,但是目前测绘档案管理的方法和机制相对落后于测绘科技的发展。本文分析了测绘档案管理的现状和发展方向,在此基础上,指出了测绘档案管理的主要任务,以及测绘档案管理机构转型的必要性。