陕西镇安石炭系--二叠系界线剖面层序地层和相对海平面变化研究   总被引：3，自引：0，他引：3  

张海军  王训练夏国王雷  张志祥 《地质通报》2004,23(4):336-344

在陕西镇安西口上石炭统逍遥阶至下二叠统隆林阶的剖面上,区分出含生物碎屑灰泥灰岩、生物碎屑粒泥灰岩、生物碎屑泥粒灰岩、生物碎屑颗粒灰岩、团块颗粒灰岩和核形石颗粒灰岩6种主要的碳酸盐岩微相类型。通过详细的微相特征分析,确定了碳酸盐岩沉积过程中的水动力状况和相对水深变化趋势,识别出低能潮下型碳酸盐旋回A1、A2及高能浅滩型碳酸盐旋回B1、B2两类4种高频旋回。根据这些高频旋回在剖面上的有序叠置型式,将镇安西口地区的上石炭统逍遥阶至下二叠统隆林阶划分出12个四级层序和5个II型三级层序地层单元,反映了这一地区晚石炭世逍遥期至早二叠世隆林期曾发生过12次四级相对海平面波动和5次明显的三级相对海平面升降。  相似文献   

用微气象方法估算淮河流域能量平衡（HUBEX／IOPl998／99）的统计分析和比较研究     

朱治林孙晓敏  张仁华 《大气科学进展》2003,20(2):285-292

利用1998和1999年HUBEX强化观测期在安徽寿县用微气象方法(波比-能量平衡法和涡度相关法)观测的资料，分析了该地区的能量平衡特征，同时与其他地区的结果进行了初步比较，结果表明：(1)用涡度相关方法测定的感热和潜热之和(H E)ec与下垫面有效能量(Rn-G)的一致性比较好，但用波比方法估算的潜热通量Ebr比用涡度相关法测定的潜热通量Eec略高(约10％)。(2)大部分净辐射能用于了地表蒸发，1998和1999年，净辐射通旦的平均日总量分别是13．89MJm^-2d-1和11．83MJ m^-2 d^-1；两年的平均波比分别是0．14(杂草)和0．06(稻田)。(3)波比在日出和日落时数值大且不稳定，白天比较小且比较稳定，另外，1999年在稻田上观测到明显的局地平流现象。(4)通过与我国其他地区的观测资料比较，淮河流域稻田的波比最小(0．06)，在内蒙古草原观测的波比值最大(0．57)。波比值的大小主要与土壤水分有关。  相似文献   

用微气象方法估算淮河流域能量平衡(HUBEX/IOP 1998/99)的统计分析和比较研究   总被引：7，自引：0，他引：7  

ZHU Zhilin  SUN Xiaomin  ZHANG Renhua 《大气科学进展》2003,20(2):285-291

In order to study energy and water cycles in the Huaihe River Basin, micrometeorological measurements were carried out in Shouxian County, Anhui Province, during HUBEX/IOP (May to August 1998 and June to July 1999). The employed techniques included Bowen Ratio-Energy Balance (BREB) and Eddy Covariance (EC) methods. In this paper, the basic characteristics of the energy balance components in the district are analyzed. Furthermore, the results are compared with those from other regions of China.The main results are as follows: (1) There was a consistency between the available energy (Rn-G) and the sum of sensible (H) and latent (E) heat fluxes measured by the EC method (H+E)ec, but Ebr was slightly larger (about 10%) than Eec; (2) Most of the net radiation (Rn) was used to evaporate water from the surface. During HUBEX/IOP in 1998 and 1999, the mean daily amounts of Rn were 13.89 MJ m-2 d-1 and 11.83 MJ m-2 d-1, and the mean Bowen Ratios (β) were 0.14 (over ruderal) and 0.06 (over paddy) respectively; (3) The diurnal variation characteristic of β was larger and unsteady at sunrise and sunset, and smaller and steady during the rest of the daytime. Local advection appeared in the afternoon over paddy areas in 1999; (4) In comparison with the results from other regions of China, the nean β was the lowest (0.06) over paddy areas in the Huaihe River Basin and the highest (0.57) during June-August 1998 in Inner Mongolia grassland. The Bowen Ratio β is mainly related to the soil humidity.  相似文献   

陕西旬邑新近纪红粘土微形态特征及其意义   总被引：9，自引：2，他引：9  

薛祥煦  赵景波 《沉积学报》2003,21(3):448-451

研究证实,新近系红土的土壤微形态特征也是判断古气候,划分对比地层的可信指标之一。用此方法研究陕西旬邑下墙晚新生代剖面的新近系及第四系最底部的岩石微形态特征及古气候,可将其分为 4个大段,自下而上第1大段,约相当于 6.8～ 5.3Ma,成壤作用以弱为主,气候是在新近纪总体暖湿背景下的凉干阶段;第 2大段,相当于5.3～ 4.2Ma,成壤作用以强为主,是新近纪最为暖湿的阶段;第 3大段,约相当于 4.2～ 2.6Ma,成壤作用较弱,气候由本阶段前半期较凉干变为后半期的较暖湿;第 4大段为进入 2.6Ma的第四纪初期,成壤作用极弱,气候由新近纪的总体暖湿突然变得冷干,在四大段的基础上还可看出次一级的微形态及气候变化与波动。此外还可根据土壤微形态特征划分中、上新统及上新统、更新统的界线。  相似文献   

The velocity structure of crust and uppermantle in the Wudalianchi volcano area in—ferred from the receiver function     

贺传松  王椿镛  吴建平 《地震学报(英文版)》2003,16(2):140-147

The Wudalianchi volcano is a modern volcano erupted since the Holocene.Its frequent occurrence of the small earthquake is considered to be indicator of active dormancy volcano.The S wave velocity structure is inferred from the receiver function for the crust and upper mantle of the Wudalianchi volcano area.The results show that the low velocity structure of Swave is widely distributed undemeath the volcano area and part of the low-velocity-zone located at shallow depth in the Wudalianchi volcano area.The low velocity structure is related to the seismicity.The Moho interface is not clear undemeath the volcano area,which may be regard to be an nec-essary condition for the lava upwelling.Therefore,we infer that the Wudalianchi volcano has the deep structural condition for the volcano activity and may be alive again.  相似文献   

Earthquake triggering and delaying caused by fault interaction on Xianshuihe fault belt,southwestern China     

张秋文  张培震  王乘  汪一鹏  Michael A Ellis 《地震学报(英文版)》2003,16(2):156-165

The coseismic Coulomb stress change caused by fault interaction and its influences on the triggering and delaying of earthquake are briefly discussed.The Xianshuihe fault belt consists of Luhuo,Daofu,Kangding,Qianning and Ganzi fault.Luohuo(Ms=7.6,1973)-Kangding(Ms=6.2,1975)-Daofu(Ms=6.9,1981)-Ms=6.0,1982)earthquake is a seismic sequence continuous on the time axis with magnitude greater than6.0.They occurred on the Luhuo.Kangding,Daofu and Ganzi fault,respectively.The coseismic Coulomb stress changes caused by each earthquake on its surrounding major faults and microcracks are calculated,and their effects on the triggering and delaying of the next earthquake and aftershocks are analyzed.It is shown that each earthquake of the sequence occurred on the fault segment with coseismic Coulomb stress increases caused by its predecessors,and most after-shocks are distributed along the microcracks with relatively larger coseismic Coulomb stress increases resulted from the main shock.With the fault interaction considered,the seismic potential of each segment along Xianshuihe fault belt is reassessed,and contrasted with those predicted results ignoring coseismic Coulomb stress change,the significance of fault interaction and its effect on triggering and delaying of earthquake are emphasized.It is con-cluded that fault interaction plays a very important role on seismic potential of Xianshuihe fault belt,and the maximal change of future earthquake probability on fault segment is up to 30.5%.  相似文献   

大别山东麓前寒武纪二长花岗质片麻岩抬升冷却过程的递进变形   总被引：4，自引：1，他引：4  

张家声  江来利  许建东 《地质科学》2003,38(1):114-127

大别山东麓北段结晶基底中的二长花岗质岩石具长石应力支撑结构,早期高级变质作用条件下的韧性推覆以长石类矿物普遍晶质塑性变形和同构造重结晶作用为典型特征,晚期在发育糜棱岩的低级韧性剪切变形阶段处于脆性状态,在其内部和边缘形成了包括微角砾岩、假玄武玻璃、黑色超糜棱岩和熔结超碎裂岩等脆性断层岩石.二长花岗质岩石中不同类型韧性和脆性断层岩石的成因和构造联系,记录了大别地体的抬升冷却历史和不同阶段构造变动的性质.  相似文献   

高温变泥质岩石中石榴石-黑云母地质温度计的应用——以胶北荆山群富铝岩石为例   总被引：6，自引：0，他引：6  

周喜文  魏春景  卢良兆 《地学前缘》2003,10(4):353-363

在对胶北荆山群麻粒岩相富铝岩石中石榴石、黑云母的成分环带进行深入研究基础上,选取不同粒径、与不同矿物相邻的石榴石、黑云母各微区点成分,利用石榴石-黑云母温度计分别进行了温度估算。确定在黑云母含量较高的岩石(V_(Grt)/V_(Bt)≤1)中,利用大颗粒石榴石(d≥1500μm)晶体核部(或靠近长英质矿物一侧的晶体幔部)成分与基质中远离石榴石等镁铁矿物处于长英质矿物之间的黑云母核部成分配合。通过石榴石-黑云母温度计可以获得相当可信的变质峰期温度。但是对于黑云母含量极低的岩石(V_(Grt)/V_(Bt)≥6),由于黑云母的成分普遍遭到了强烈改造。使得温度估算结果异常偏低,因此不适合采用石榴石-黑云母温度计估算峰期温度。同一岩石中,采用不同的相邻石榴石-黑云母矿物对晶体边缘成分获得的温度值差异较大,反映它们在峰期后发生Fe-Mg交换反应并达到封闭温度平衡状态的程度不同,因此利用石榴石-黑云母温度计难以获得准确的封闭温度。通过热力学计算,建立了一个新的石榴石-黑云母温度计公式。确定胶北荆山群所经历的变质峰期温度为720～770℃,峰期后最低相对封闭温度为480～500℃。  相似文献   

油气藏自然电场的微泡运移生电模型     

文百红  林蓓 《地质与勘探》2003,39(Z1):99-102

油气藏上方存在自然电位异常,经典理论认为这是由于氧化还原电池效应所产生的.但这种观点无法解释油气藏上方自然电位异常空间变化大,甚至还出现明显的正异常现象.模拟油气微渗漏气泡上升迁移的实验表明,由于气水界面偶电层具有明显的负ζ电位,不同数量气泡在不同盐度水溶液中上升迁移时均起着一种天然的负电荷流的作用,因此可产生一定的自然电场.在此基础上,建立了油气微渗漏气体运移生电模型.该模型为自然电位资料预测油气藏的埋藏深度提供了定量解释依据.初步研究表明,自然电场的性质和异常强度与地面测量资料有较好的一致性.  相似文献   

峡东陡山沱组一些微化石的再研究     

曹芳 《华北地质》2003,26(3):145-150

陡山沱期在生物进化中是一个重要的阶段，这一时期不仅在动物界而且在植物界均有明显的变化。峡东陡山沱组多种多样的微化石已有众多报道。这个生物群落包括浮游的球形体、底栖的藻丝体和瓶状微化石。最近笔者重新研究了陡山沱组薄片中的微化石，这些微生物三维地保存在几乎未蚀变的条件下，以丰富的具刺疑源类为特征，主要者有Baltisphaeridium，Filisphaeridium，Tianzhushania和Comaspheridium等。陡山沱组的碳酸盐岩相具刺疑源类和瓶状微化石与产自Spitsbergen的化石近似。这似乎说明陡山沱组与位于Spitsbergen东北部的Svanbergfjellet组沉积可以对比。但由于化石只发现在少数薄片中，因此上述结论可能是片面的，这些化石可能只代表峡东陡山沱组生态环境的一部分。  相似文献