华南二叠纪层序地层与盆地演化   总被引：31，自引：2，他引：29  

陈洪德  王成善 《沉积学报》1999,17(4):528-535

新兴的层序地层学,是盆地分析的重要手段。华南二叠纪是华南板块海西-印支阶段盆地演化的重要时期,沉积盆地类型划分为克拉通盆地、板内及板缘伸展盆地,以及东吴运动后出现的前陆盆地和弧后盆地。南方二叠系由11个层序和1个半超层序组成,不同类型沉积盆地中层序地层具有不同的层序特征和充填形式。二叠纪是海西-印支期盆地演化由成熟到消亡的转折阶段,它们发育于扩张环境下,总体上是由两个克拉通盆地夹持一个伸展盆地。两个克拉通盆地的发展不均衡,中央伸展盆地沿着加里东的拼合带发育。这一古地理古构造格局与加里东期十分相似,由此认为,华南晚古生代沉积的构造背景,并不是稳定的克拉通环境。  相似文献   

初始场估计共轭同化方法的精确化   总被引：2，自引：1，他引：1  

吴诚鸥  沈桐立 《南京气象学院学报》1999,22(1):61-68

通过例子,说明对偏微分方程模型使用共轭同化方法时,同周期性条件的重要性,提出尽可能精确地使用共轭同化方法于偏微分方程模型的办法及对有些方程不含ｅ↓ｕ／ｅ↓项时,其相应差分方程模型精确共轭同化方法。  相似文献   

Forced regression and its sedimentary response to continental lacustrine rift basin: A case of the Member 3 of Shahejie Formation in Laizhouwan sag,Bohai Bay Basin          下载免费PDF全文

Qin Yi  Zhu Xiao-Min  Wang Tong  Guo Cheng  Xie Shuang-Hui 《古地理学报》1999,22(3):457-468

Falling stage systems tract(FSST)is an offlap strata with strong relationship with hydrocarbon exploration,which is driven by relative lake-level fall and developed above the highstand systems tract and below the lowstand systems tract of a new sequence. It has no relationship with sediment supply. Based on the theory of sequence stratigraphy and sedimentology,3D seismic data,drilling core data,and well-logging data were comprehensively analyzed. The study showed that the FSST strata was formed in the Member 3 of Shahejie Formation in the Laizhouwan sag. The FSST can be divided into three units,namely as units P1,P2,and P3 from bottom to top. The P1 is the first unit of progradation downlap the bottom of the FSST. The top of the unit P3 is a sequence boundary exhibits subaerial unconformity. The seismic profile along the source direction is characterized by the low-angle oblique progradation reflection that downstream the center of lake basin from west to east. Incised valleys developed on the top of the FSST perpendicular to the source direction. Gamma-ray logging response is manifested by a series of funnel-shaped complex,indicating that the sedimentary response of the FSST was a cycle of coarsening-upward parasequence sets. Comprehensive studies on core interpretation and well-logging analysis showed that the FSST was a fluvial-delta sedimentary system with slumped fan deposits associated with the delta front. Consequently,the FSST is a common result of relative dry climate and falling of lake level,considering regional tectonic evolution,sediment supply,and paleo-climate change. The discovery of the FSST in the Laizhouwan sag has an important geological significance for the sedimentological interpretation,and it offers a guidance for further oil exploration in the study area. In addition,it also serves as a significant reference for future research on the FSST development and exploration in the continental lacustrine rift basin.  相似文献   

THE CHARACTERISTICS OF SUMMER MONSOON AND TRANSPORT OF MOISTURE IN A HEAVY RAIN OVER SOUTH CHINA IN 1994   总被引：1，自引：1，他引：0  

吕梅  成新喜  陈中一  陆汉城 《热带气象学报(英文版)》1999,5(1):60-66

The trajectory of atmospheric particles and material lines on an isentropic surface are computed using the Lagrangian method. It is shown that the 1994 heavy rain in South China was closely linked to the summer monsoon, especially the tropical monsoon in East Asia. which plays a decisive role. The method is useful in tracking the source area and evolution of water moisture and analyzing the transporting part of airflow for water moisture.  相似文献   

区域空气质量数值预报模型   总被引：6，自引：3，他引：3  

安俊岭  王自发  黄美元  陶树旺  程新金  叶红 《气候与环境研究》1999,4(3):244-251

给出了区域尺度空气质量数值预报模型的基本物理构架, 重点介绍了欧拉型输送／沉降模式对各种物理 （沉降、输送）、化学 （气相化学与液相化学） 过程、初值与边界条件等问题的处理／简化; 利用本模型作了一周的预报实验, 实验结果与分析说明, 区域空气质量数值预报模型能够较好地反映全国重点城市的空气质量以及污染物随时间的演变态势; 最后, 指出了需要进一步完善的工作。  相似文献   

NOx与NMHC的变化对O3 生成量的影响   总被引：8，自引：0，他引：8  

安俊岭  韩志伟  王自发  黄美元  陶树旺  程新金 《大气科学》1999,23(6):753-761

利用LLA-C光化学反应机制,在NOx体积分数φ变化范围很广（1.75～350.0,单位为10-9,以下同）的条件下,选择18种NMHC与NOx的体积分数比（2.0～200.0）模拟分析在什么条件下NMHC的改变对臭氧生成量不大敏感而主要依赖于NOx的大小,同时给出相应条件下OH模拟值的变化。结果表明,OH峰值均出现在φ(NMHC/NOx)≈8.0。所找条件是φ(NOx)≤50.0时要求φ(NMHC/NOx)≥60.0;φ(NOx)>50.0时需要8.0≤φ(NMHC/NOx)≤28.0。相应O3生成量的最大误差小于20%。该条件正适合我国典型污染城市当前φ(NOx)水平和φ(NMHC/NOx)范围,可用于我国区域尺度空气质量模拟。与实测资料的对比还有待进一步开展。  相似文献   

广东长坑银金矿区地层研究的新发现及意义   总被引：4，自引：1，他引：3  

张湖  谢岩豹  程景平  王秀璋  李统锦  梁华英 《广东地质》1999,14(1):78-78,T001

广东长坑银金矿区的地层,原认为由下石炭统及土三叠统组成,两者呈断层接触。近来,在原这为相门桥组的硅质岩中发现了晚二叠世放射虫化石;在小坪组所夹的在 中发现有早石炭世有孔虫化石;在某些地段还发现“梓门桥组”硅质岩与“小坪组”整合接触。据此认为矿区内可能有中石炭世至中三叠世地层存在。目前对上述新发现的解释均不够圆满,因此对长坑矿区的地层学在必要深入研究,无论研究结论如何,都将对矿区的地层划分、地质构造  相似文献   

岩湾矿段风化磷矿形成条件及其三种类型     

陈拥军 《化工矿产地质》1999,21(4):225-230

湖北省鹤峰磷矿走马矿区岩湾矿段风化磷矿是湖北境内首次探明的一中型风化磷矿。矿床成因类型有风化残余型、风化淋滤型、洪积型砂磷矿等三类。在时间上 ,风化淋积型矿体位于风化残余型矿体之下 ,是风化残余型的继承发展。在雨水和洪水冲刷下 ,风化残余磷矿在适当的低洼地带堆积成洪积型砂磷矿。对这种风化矿的勘探应因地制宜 ,灵活运用。对岩湾矿段风化磷矿的成因探讨和勘探研究为东山峰寻找和勘探类似风化磷矿积累了经验。  相似文献   

四川泸定昔格达组时代及其新构造意义   总被引：30，自引：1，他引：29  

蒋复初  吴锡浩  肖华国  赵志中 《地质学报》1999,73(1)

川西高原东南部边界带内侧沪定大渡河西岸的海子坪,在高出大渡河水面约920m的谷肩上保存着一套厚约411 m的昔格达组河湖相地层。磁性地层初步研究表明,以距顶深度386.0m处为界,以上为高斯正向极性带,以下为吉尔伯特反向极性带。对比Cande和Kent的极性年表,沪定昔格达组的年代约4.29～2.60 Ma BP,地质时代应属上新世中、晚期。将沪定昔格达组与高原边界带外侧的汉源昔格达组进行对比,地层中记录的松山反向极性时与高斯正向极性时界面分别处于海拔2220 m和1040 m左右,两者之间的高为1180 m,这应是2.6 Ma BP以来川西高原东南部边界带两侧地块相对隆升的结果。  相似文献   

Isotopic constraints on the Easter Seamount Chain source     

Q. C. Cheng  J. D. Macdougall  P. Zhu 《Contributions to Mineralogy and Petrology》1999,135(2-3):225-233

New isotopic data (Sr, Nd and Pb) for lavas from Easter and Salas y Gomez Islands, and nine seamounts along the length of the Easter Seamount Chain (ESC) to the east of these islands, exhibit a regular behavior that is consistent with two-component mixing between a MORB-like source and more enriched mantle (the Easter Plume source) characterized by relatively radiogenic Pb and unradiogenic Sr. Based on the linearity of mixing trends on the isotope diagrams, the plume source appears to have maintained approximately the same isotopic composition over the 20 to 30 Ma history of the Easter Plume sampled by the seamounts. In current nomenclature, the plume source resembles a mix of predominantly HIMU mantle with a small amount of EMI. The proportions of MORB and plume source mantle sampled by the lavas erupted along the ESC vary in a systematic way, with Easter Island and seamounts to the west containing larger fractions of the MORB component than Salas y Gomez Island and the older seamounts to the east. This variability is probably a reflection of the nearness to the spreading center, and therefore lithospheric thickness, at the time of volcanism Received: 27 April 1998 / Accepted: 11 December 1998  相似文献