岩层离距图法研究沉积岩断裂发育史——以松辽盆地敖古拉断裂为例

利用断裂活动过程中留下的各种地质标记研究断裂发育史是比较困难的 ,已有的研究方法主要可归纳出七种 ,都存在局限性。岩层离距图法是以地震剖面为基础 ,将穿过断裂的各剖面上的标志层投影到沿断裂走向的铅垂面上 ,得到多组标志层的垂向断距数据 ,然后用下部各标志层的断距减去最上部标志层的断距 ,并作多轮次计算 ,直到最后的断距差近似为零或仅剩一个非零标志层。每一轮次计算代表一个活动期次 ,如果出现负值 ,则表示有构造反转。对松辽盆地敖古拉断裂作了实例计算 ,结果为该断裂发育经历了三个正断活动期和一个逆断活动期 ,与盆地区域性活动有些差别。岩层离距图法比起其他已有方法 ,可靠程度大大提高     

鄂尔多斯盆地奥陶系海相碳酸盐岩生烃性能与中部长庆气田气源成因研究

用激光 -荧光显微镜等有机岩石学方法 ,挑选样品中有明显生、排烃现象的碳酸盐岩 ,再以测定的这类碳酸盐岩的有机碳含量为依据 ,确定本区高成熟碳酸盐气源岩残余有机碳的下限指标用 0 .13%～ 0 .14 %比较合理。根据碳酸盐岩储层孔隙中充填沥青和皮膜状残余沥青的分布和含量 ,论证了陕参 1井等奥陶系碳酸盐岩地层在地质历史中 ,存在若干油气有效储层。采用连续升温 ,步进取样的热模拟实验方法 ,揭示了本区煤与碳酸盐岩干酪根随热演化作用增强 ,烃类气体产物的干燥系数增大 ,δ1 3C1 、δ1 3C2 明显变重的规律 ,并根据样品实验结果推算 ,本区石炭系—二叠系煤最大生气阶段的δ1 3C1 应为 - 2 7‰～ - 2 8‰ ,碳酸盐岩最大生气阶段的δ1 3C1 应为- 31.7‰～ - 33‰。在气源成因判识中 ,根据主生气期阶段对天然气成藏储聚的贡献最大、甲烷碳同位素较重以及长庆气田风化壳气藏天然气δ1 3C1 重值区并不与石炭系—二叠系煤的镜质组反射率高值区匹配的现象等进行气源判识 ,认为长庆奥陶系风化壳气藏 ,具有下古生界海相碳酸盐岩气与上古生界石炭系—二叠系煤成气的混源成因     

鄂尔多斯盆地北部黄土沙漠区隐蔽薄气层预测

长庆油田公司针对黄土沙漠区低孔、低渗、薄气藏的地震目标处理,经过多年的探索与实践,已形成了一套适合该类气藏特点的储层横向预测技术。在榆林、乌审旗、苏里格庙和神木等地区的上古生界天然气勘探、开发阶段取得了显著效果,使长庆油田上古生界天然气储量连续八年保持稳定增长。本文详细剖析了该技术的应用效果及经验。     

Accuracy analysis, dem generation and validation using russian tk-350 stereo-images

TK-350 stereo-scenes of the Zonguldak testfield in the north-west of Turkey have been analysed. The imagery had a base-to-height ratio of 0·52 and covered an area of 200 km × 300 km, with each pixel representing 10 m on the ground. Control points digitised from 1:25 000 scale topographic maps were used in the test. A bundle orientation was executed using the University of Hanover program BLUH and PCI Geomatica OrthoEngine AE software packages. Tests revealed that TK-350 stereo-images can yield 3D geopositioning to an accuracy of about 10 m in planimetry and 17 m in height. A 40 m resolution digital elevation model (DEM) was generated by the PCI system and compared against a reference DEM, which was derived from digitised contour lines provided by 1:25 000 scale topographic maps. This comparison showed that accuracy depends mainly on the surface structure and the slope of the local terrain. Root mean square errors in height were found to be about 27 and 39 m outside and inside forested areas, respectively. The matched DEM demonstrated a systematic shift against the reference DEM visible as an asymmetric shift in the frequency distribution. This is perhaps caused by the presence of vegetation and buildings.     

Uplift and subsidence from oblique slip: the Ganos–Marmara bend of the North Anatolian Transform, western Turkey

Bends that locally violate plate-motion-parallel geometry are common structural elements of continental transform faults. We relate the vertical component of crustal motion in the western Marmara Sea region to the NNW-pointing 18° bend on the northern branch of the North Anatolian Fault (NAF-N) between the Ganos segment, which ruptured in 1912, and the central Marmara segment, a seismic gap. Crustal shortening and uplift on the transpressive west side of the bend results in the Ganos Mountain; crustal extension and subsidence on the transtensional east side produce the Tekirdağ Basin. We propose that this vertical component of deformation is controlled by oblique slip on the non-vertical north-dipping Ganos and Tekirdağ segments of the North Anatolian Fault. We compare Holocene with Quaternary structure across the bend using new and recently published data and conclude the following. First, bend-related vertical motion is occurring primarily north of the NAF-N. This suggests that this bend is fixed to the Anatolian side of the fault. Second, current deformation is consistent with an antisymmetric pattern centered at the bend, up on the west and down on the east. Accumulated deformation is shifted to the east along the right-lateral NAF-N, however, leading to locally opposite vertical components of long- and short-term motion. Uplift has started as far west as the landward extension of the Saros trough. Current subsidence is most intense close to the bend and to the Ganos Mountain, while the basin deepens gradually from the bend eastward for 28 km along the fault. The pattern of deformation is time-transgressive if referenced to the material, but is stable if referenced to the bend. The lag between motion and structure implies a 1.1–1.4 Ma age for the basin at current dextral slip rate (2.0–2.5 cm/year). Third, the Tekirdağ is an asymmetric basin progressively tilted down toward the NAF-N, which serves as the border fault. Progressive tilt suggests that the steep northward dip of the fault decreases with depth in a listric geometry at the scale of the upper crust and is consistent with reactivation of Paleogene suture-related thrust faults. Fourth, similar thrust-fault geometry west of the bend can account for the Ganos Mountain anticline/monocline as hanging-wall-block folding and back tilting. Oblique slip on a non-vertical master fault may accommodate transtension and transpression associated with other bends along the NAF and other continental transforms.     

宁夏中北部地区沙尘暴天气发生过程中的不稳定条件分析

从沙尘暴的形成条件入手，对宁夏中北部地区近30a来沙尘暴天气发生过程中的不稳定条件进行了较为详尽的分析。结果表明：沙尘暴发生三前，大气的不稳定性明显增强；沙尘暴天气发生时不稳定性主要发生在700hPa以下，最为突出的是850hPa以下；沙尘暴发生过程中不稳定性达到最强。     

华北克拉通西部鄂尔多斯地块长城系碎屑锆石LA-ICP-MS U-Pb测年及意义

自1.85 Ga西部陆块与东部陆块沿中部造山带碰撞拼合形成统一的华北克拉通之后,中—新元古代克拉通经历了广泛的陆内拉伸,形成了熊耳裂陷槽、燕辽裂陷槽、渣尔泰—白云鄂博—化德裂陷槽及东缘裂谷系。前人根据钻井资料及区域地层对比认为鄂尔多斯地块变质基底之上沉积了中元古代长城系—蓟县系。其中,长城系下部主要为石英岩夹板岩,上部为粉砂质板岩、硅质板岩及含燧石条带白云质灰岩与石英砂岩;蓟县系以白云岩为主,夹少量砂岩、页岩。本文对采自鄂尔多斯地块6口钻井中的长城系进行了碎屑锆石年代学研究。结果表明,鄂尔多斯地块长城系浅变质沉积岩的碎屑锆石年龄组成了1.60 Ga、1.85 Ga、1.95 Ga、2.35 Ga和2.50 Ga等峰值。与华北克拉通内部中—新元古代沉积岩碎屑锆石年龄峰值对比结果表明,长城系沉积岩的碎屑物质来自华北克拉通内部。结合区域钻井资料及前人研究成果,推断中元古代鄂尔多斯地块北缘及东缘为隆起剥蚀区,西南部为沉积区,其西南缘为被动大陆边缘,与北秦岭地体之间被宽坪洋分隔。     

Optimization and Parametrical Investigation to Assess the Reconstitution of Different Types of Indian Sand Using Portable Travelling Pluviator

By using the air pluviation technique, it is aimed to achieve the desired relative density with uniform void ratio throughout the specimen in order to maintain the homogeneity and to avoid the spatial variability. Further, in order to achieve the maximum deposition intensity, a systematic optimization study has been carried out rigorously in a test tank to determine the diameter of the orifice to be employed for the sieve plates of different porosity and the number of sieve plates to be installed in the diffuser sieve sets. The study has been conducted with four different patterns of sieves with different porosity to achieve a wide range of relative densities for four different uniformly graded Indian sands. The dynamic penetrometer which is considered to be one of the cost effective instruments has been efficiently used to determine the soil resistance at various locations of the test tank for every given height of fall in order to check the uniformity of placement density throughout the sand bed. The study reveals that the sand beds of different relative densities could be achieved using different patterns of diffuser sieves at optimum sand flow rate without compromising the uniformity. The effect of height of fall as well as porosity of diffuser sieves on the relative density of different sands has been studied in detail. The deposition intensity and the relative density obtained from the present study are compared with the values available in the literature.