共查询到20条相似文献，搜索用时 46 毫秒
1.
本文讨论了河西走廊东部地区早二叠世地层研究的有关问题,认为甘肃山丹青羊泉下二叠统剖面是北祁连山—河西走廊地区的重要代表剖面之一。以该剖面研究为依据,提出走廊东部地区下二叠统的进一步划分方案,分析该区早二叠世地层岩性特征差异的原因,并与走廊西部地区同期地层进行对比,进一步明确了大黄沟组的含意。 相似文献
2.
通过对野外露头和钻井资料的重新梳理，运用 Ｖａｉｌ经典层序地层学理论方法，对元坝地区吴家坪组进行了层序地层划分。结合三维地震资料分析，选择典型连井剖面进行地层层序对比，建立了等时层序地层格架，在层序格架内开展了沉积充填作用的研究。研究表明:①元坝地区吴家坪组地层划分为三段，吴一段底部岩性以泥岩、炭质泥岩及铝土岩为主，中上部为生屑灰岩，吴二段下部岩性为泥岩、泥灰岩，上部为生屑灰岩夹薄层硅质灰岩，吴三段岩性以厚层生屑灰岩为主，吴一段为一个三级层序ＳＱ１，吴二、吴三段组成一个三级层序ＳＱ２；②吴家坪组继承了茅口组的沉积格局，ＳＱ１和 ＳＱ２早中期为碳酸盐岩缓坡沉积模式，ＳＱ２晚期在峨眉地裂运动的拉张作用下，出现“台盆分异”，具有发育台缘高能浅滩的沉积背景，且地震响应特征明显；③吴三段台缘高能浅滩储层发育，且具有“多元供烃、近源富集”的特征，生储盖配置好，成藏条件优越，展示了良好的勘探潜力。元坝地区吴三段发育台缘浅滩相储层这一认识将有利拓宽上二叠统油气勘探领域。 相似文献
3.
新疆若羌县阿热力一带位于东昆仑西段北坡、柴达木盆地西南缘。地层区划隶属于秦祁昆地层区、东昆仑-中秦岭地层分区,该区冰沟群分布广泛。对该区开展区域地质调查、对冰沟群的沉积环境和层序地层进行分析研究具有重要地质意义。在开展区域地质调查中,采用路线调查、剖面测量、实验测试等方法对冰沟群的岩性特征、岩石组合、地球化学特征、古生物特征以及形成时代等进行了系统研究,依据岩石组合特征将其划分为狼牙山组和丘吉东沟组。把该区冰沟群与区域上都兰县冰沟群层型剖面进行了对比,通过对比研究,认为该区的冰沟群与都兰县冰沟群层型剖面具明显可对比性。依据岩性特征、岩石组合特征、古生物特征等,对冰沟群沉积环境进行了分析,认为狼牙山组沉积环境属于潮下较深水陆棚相低能环境;丘吉东沟组属于浅海陆棚相带内缘斜坡沉积环境。并对冰沟群层序地层进行了划分,将其划分为2个Ⅲ级层序,即第一层序（B-1）和第二层序（B-2）。 相似文献
4.
根据层序地层学理论,研究他拉哈西地区的层序地层格架及沉积体系特征;根据层序界面岩性—电性及地震反射特征,将泉头组四段到嫩江组三段地层划分为2个二级层序、6个三级层序、17个四级层序;综合利用岩心、测井、地震等资料,确定层序内部沉积特征;根据层序发育特征,确定层序格架内的各时期沉积相平面分布规律.结果表明:研究区主要以三... 相似文献
5.
6.
松辽盆地外围西部上二叠统林西组主要分布于西拉木伦河断裂以北、贺根山—黑河断裂以南,以及稍北的内蒙古地区。根据野外勘察、实测剖面和岩心观察资料,建立研究区上二叠统林西组沉积亚相岩性组合模式,明确晚二叠世林西组岩相古地理特征。结果表明:研究区上二叠统林西组主要发育湖泊、扇三角洲、河流3种沉积相,以及滨浅湖、半深湖、扇三角洲平原、扇三角洲前缘、辫状河、滨浅海6种沉积亚相,以滨浅湖亚相为主,滨浅海亚相分布局限,在林西县官地剖面顶部出现。松辽盆地西部上二叠统林西组,构成以西拉木伦河与贺根山—黑河断裂为主要控制区的、以南北向物源供给为主的滨浅湖—扇三角洲—河流沉积体系。该结果对松辽盆地外围西部晚古生代油气勘探具有重要意义。 相似文献
7.
根据１∶５万和１∶２５万区域地质调查和全国立典性剖面调查成果，将林西组划分为５个岩性段，原林西组六段划分为老龙头组，并揭示出林西组官地剖面的地层褶皱重复多次，而非前人的单斜地层序列。根 据 古 植物、双壳类和孢粉等生物地层确定林西组地质时代为晚二叠世，老龙头组地质时代为早三叠世早期。基 于 古 生物、沉积构造、碳酸盐岩微相及碳氧同位素分析等多方面证据确定出林西地区林西组和老龙头组为陆相河湖沉积，
其沉积演化序列为河流→浅湖→深湖→浅滨湖，与天山－兴蒙地区二叠纪主要的陆相盆地沉积演化序列一致。 相似文献
其沉积演化序列为河流→浅湖→深湖→浅滨湖，与天山－兴蒙地区二叠纪主要的陆相盆地沉积演化序列一致。 相似文献
8.
9.
通过对宁阳煤田茅庄井田煤系地层综合分析,揭示了茅庄井田的煤层岩性特征和沉积环境。研究结果表明:该井田主要含煤地层为早二叠世山西组和晚石炭世—早二叠世太原组,总厚度约220 m。可采或局部可采者4层,即3上煤层,3下煤层,16煤层、17煤层,平均总厚度为9.52 m。本井田内3上煤层、3下煤层为主采煤层。含煤地层为石炭—二叠纪月门沟群,其中山西组是该区最重要的含煤地层。沉积环境为从海相沉积为主到以陆相沉积为主的转变过渡时期,岩石地层反映了典型的海陆交互相的沉积特征;在海陆交互期海退三角洲平原上供应了大量的泥炭沼泽,为茅庄井田煤层提供了物质基础。其中太原组为典型的海陆交互相沉积,沉积相环境稳定,变化小,标志层及煤层层位清楚、稳定,煤层沉积层序规律性强,是区域地层对比的稳定层位。 相似文献
10.
《地球科学与环境学报》2015,(4)
四川盆地上二叠统—下三叠统碳酸盐岩地层中富集天然气,天然气藏的分布受优质烃源岩和礁滩相储层的控制。为了揭示四川盆地沉积演化背景下天然气的富集规律及预测成藏有利区,对晚二叠世—早三叠世扬子古板块地质构造背景进行分析,讨论地质构造背景控制下四川盆地晚二叠世—早三叠世沉积演化特征;根据不同时期构造和沉积演化特征确定优质烃源岩和储层的发育机理和分布范围;结合天然气成藏模式的认识,确定天然气成藏有利区。结果表明:四川盆地晚二叠世—早三叠世海湾及其后陆棚的发育演化控制了该区龙潭组主力烃源岩与长兴组—飞仙关组礁滩相储层的发育分布,形成了下生上储的有利配置关系;川东北地区长兴组—飞仙关组台地边缘礁滩相储层邻近龙潭组海湾相优质烃源岩的区域为天然气成藏最有利区。总之,四川盆地晚二叠世—早三叠世沉积演化特征控制了海相优质烃源岩和储层的发育分布,决定了天然气的富集与分布。 相似文献
11.
王明远 《中国地理科学(英文版)》1993,3(4):376-380
We have made progress in medico-chemical geography as follows: the correlative law of organism with geochemical environment; the geochemico-ecological classification of chemical elements; the types of formative cause of biogeochemical provinces in China; the parabolic correlation between contents of iodine in drinking water and prevalence rate of endemic goiter; the discovery and proof of the low selenium zone in China; the successive discovery of endemic fluorosis of the types of pollution from burning coal, drinking high fluoride tea and high fluoride table salt from the year 1978; the study on chemical geography of schistosomiasis and the compilation of the Atlas of Endemic Diseases and Their Environments in the People's Republic of China. 相似文献
12.
13.
随着信息社会的发展，新技术和新媒体的出现必然影响学校现代教育的发展。通过阐述发展学校电化教育的应注意的问题，探讨了解决问题的方法。 相似文献
14.
15.
16.
We used long term monitoring data to evaluate changes in abundance and species dominance of small-jellyfish (collected with zooplankton net whose bell diameter was less than 5 cm) between 1991 and 2009 in the Jiaozhou Bay, China. Zooplankton samples were vertically towed with conical plankton net from near-bottom to surface, identified microscopically, and mapped in time-space using Grapher 7.0 and Surfer 8.0. Results show that the abundance of small-jellyfish throughout the bay had been increasing during 2001-2009 on average of 15.2 ind./m 3 , almost 5 times higher than that between 1991 and 2000. The occurrence of peak abundance shifted from spring to summer after 2000, and two peaks appeared in spring and summer, respectively, after 2005. Both the abundance and the frequency of blooms of small-jellyfish increased after 2000 in the bay. In addition, the biodiversity of jellyfish has increased significantly in recent years with a change in dominant species. Several new dominant species appeared after 2000, including Rathkae octopunctata in winter, Phialidium hemisphaericum in spring, summer, and autumn, Phialucium carolinae in spring, and Pleurobrachia globosa in summer and autumn, while some previous dominant species throughout the 1990s (Eirene ceylonensis, Zanclea costata, Lovenella assimilis, and Muggiaea atlantica) were no longer dominant after 2000. The abundance of small-jellyfish was positively correlated with the density of dinoflagellates, and the abundance of zooplankton. We believe that the changes in smalljellyfish abundance and species composition were the result of eutrophication, aquaculture and coastal construction activities around the bay. Concurrently, seawater warming and salinity decrease in recent decades promoted the growth and reproduction of small-jellyfish in the bay. 相似文献
17.
18.
19.
刘希林 《中国地理科学(英文版)》1995,5(3):275-287
ＲＥＣＥＮＴＤＥＶＥＬＯＰＭＥＮＴＳＩＮＤＥＢＲＩＳＦＬＯＷＲＥＳＥＡＲＣＨＩＮＩＴＡＬＹＭａｒｃｈｉＬｏｒｅｎｚｏ；ＴｅｃｃａＰｉａＲ．（ＩｎｓｔｉｔｕｔｅｆｏｒＰｒｅｖｅｎｔｉｏｎｏｆＨｙｄｒｏｌｏｇｉｃａｌａｎｄＧｅｏｌｏｇｉｃａｌＨａｚａｒｄ... 相似文献
20.
Community Participation in Forest Resource Management in Nepal 总被引：2，自引：1，他引：1
KeshavL.Maharjan 《山地科学学报》2005,2(1):32-41
Livelihood of the people in Nepal hills depends much upon forest resources in addition to farming as forest plays a critical role in the well being of the farming households where access to alternative sources, such as energy for cooking, nutrition for animals, materials for fertilizer and constructing materials for shelter, are limited. Thus, the well being of the people in the hills is directly affected by the management of these forest resources. This issue was addressed in this paper by examining the forest resource management practices and its effect on well being of rural people in two different stages in a village lying in the steep hill of Mahabharat Range in the southern hills of Kathmandu valley, Lalitpur District. The main ethnic/caste groups in the villageare Brahmin/Chhetri (high Hindu caste),Magar/Tamang (Tibeto Burmans) and Kami (occupational caste: cobbler). Currently there are four community forest users groups, with mixed ethnic membership, organized to manage the forest resources. The endowments, weak institutional settings, before 1990 helped the Bhramins, Magars and Tamangs to get access into the private forest endowment, which made them easy to get access to the forest resources, mainly fuel wood, fodder and timber in 1990 and enhanced their well beings. But the socially backward Kami could not get benefit from the institutions that existed during that time and had less chance to enhance their well beings. After the set up of different endowments during late 199os, i.e.,hand over of forest management to users groups in line with the concept of community forest,environment to use the forest resources became better for all the groups, along with the management of the forest. This enhanced the well beings of all the groups in the study village. However, the ability of Kami to use the forest resources to enhance their well beings was still lacking behind. The reason was partially due to the difference in endowments carried over from the endowments before 199o, and partly due to their occupational work and location of their settlements. 相似文献