基于EGM2008和剩余地形模型的区域似大地水准面精化方法

利用EGM2008计算重力场模型高程异常,结合SRTM和DTM2006.0计算剩余地形模型,进而计算RTM高程异常,以弥补EGM2008重力场模型短波信号缺失的不足。从实测高程异常中减去重力场模型高程异常以及RTM高程异常,得到残余高程异常。利用曲面拟合方法拟合残余高程异常模型,解决高程基准系统偏差问题。通过实际GPS/水准数据计算证明,该方法能显著提高GPS点的高程异常计算精度,达到精化区域似大地水准面的目的。     

湖相深水细粒物质的混合沉积作用探讨*

沉积物的混合是自然界的普遍现象,湖盆中广泛发育的深水细粒沉积岩本身就是一类混积岩。以东营凹陷古近系沙河街组三段下亚段—沙河街组四段上亚段细粒沉积岩为研究对象,通过厘米级岩心观察描述、小型沉积构造解剖、岩石薄片观察、X射线衍射全岩矿物分析及微量元素测试等方法,研究细粒物质的产出状态和混合方式;分析湖盆流体、气候及水体性质对细粒物质迁移、混合、沉积的控制作用,尝试探讨细粒物质的混合沉积机制。结果表明,湖相深水细粒沉积岩既有物质成分上的混合,也有结构的混合,且在宏观与微观的不同尺度均存在混合;混合沉积作用有均匀混合、纹层叠置混合、不均匀团块状混合等类型。纹层叠置混合沉积是最主要的混合沉积方式,依据纹层接触关系、所占比例及矿物产出状态可分为泥砂—灰纹层叠置混合型、泥—灰纹层叠置混合型、泥砂粒序—灰纹层叠置混合型、灰—泥—云纹层叠置混合型等。湖相深水细粒物质的混合沉积作用类型多且往往受多个因素同时控制,气候及水动力条件是控制细粒混合沉积岩发育的最主要因素,不同流体(浊流和底流)作用下的细粒沉积物混合作用存在差异。气候引起湖水性质变化及水体分层,从而控制不同类型细粒物质的絮凝沉降及化学沉积。不同构造部位、不同水体深度的混合作用不同;相同构造部位在垂向上也存在混合沉积方式的差异。     

扩频微波网桥在新疆测震网络中的应用

以频率为2.4 GHz和5.8 GHz设备为例,对扩频微波网桥在新疆测震网络中的应用范围进行阐述;根据实际工作中无线网桥的安装架设经验,对在不同条件、不同环境下可能出现的问题提出相应解决方案.     

A device for rainfall simulation in geotechnical centrifuges

Rainfall-induced slope instabilities are ubiquitous in nature, but simulation of this type of hazards with centrifuge modelling still poses difficulties. In this paper, we introduce a rainfall device for initiating slope failure in a medium-sized centrifuge. This rainfall system is simple, robust and affordable. An array of perforated hoses is placed close above the model slope surface to generate the raindrops. The rainfall intensity depends on the centrifuge acceleration and the flow rate of the water supply, which is controlled by the size and number of the tiny pinholes in the hose walls. The rainfall intensities that are tested range from 2.5–30 mm/h, covering the intensity range of moderate, heavy and torrential rainfall events. Our model test with rainfall-induced slope failure shows that this system is capable of generating relatively uniform rainfall of wide intensities and leads to various patterns of slope failure.

     

The thermal history and uplift process of the Ouxidaban pluton in the South Tianshan orogen: Evidence from Ar-Ar and (U-Th)/He

The uplift and exhumation process in the Tianshan orogen since the late Paleozoic were likely related to the preservation of ore deposits. This study involved reconstructing the whole tectonic thermal history of the Ouxidaban pluton in central South Tianshan Mountains based on hornblende/plagioclase Ar-Ar and zircon/apatite(U-Th)/He methods. The thermal history and uplift process of central South Tianshan Mountains since the late Paleozoic were analyzed according to the results of previous works and cooling/exhumation rate features. The hornblende yields a plateau age of 382.6±3.6 Ma, and the plagioclase yields a weighted mean age of 265.8±4.9 Ma. The Ouxidaban pluton yields weighted mean zircon(U-Th)/He age of 185.8±4.3 Ma and apatite(U-Th)/He age of 31.1±2.9 Ma, respectively. Five stages of tectonic thermal history of South Tianshan Mountains since the late Paleozoic could be discriminated by the cooling curve and modeling simulation:(1) from the latest Silurian to Late Devonian, the average cooling rate of the Ouxidaban pluton was 7.84°C/Ma;(2) from the Late Devonian to the latest Middle Permian, the average cooling rate was about 2.07°C/Ma;(3) from the latest Middle Permian to the middle Eocene, the cooling rate decreased to about 0.68°C/Ma, suggesting that the tectonic activity was gentle at this time;(4) a sudden increase of the cooling rate(5.00°C/Ma) and the exhumation rate(0.17 mm/a), and crustal exhumation of ~1.83 km indicated that the Ouxidaban pluton would suffer a rapid uplift event during the Eocene(~46?35 Ma);(5) since the middle Eocene, the rapid uplift was sustained, and the average cooling rate since then has been 1.14°C/Ma with an exhumation rate of about 0.04 mm/a and an exhumation thickness of 1.33 km. The strong uplift since the Cenozoic would be related to a far-field effect from the Indian and Eurasian plates' collision. However, it was hysteretic that the remote effect was observed in the Tianshan orogenic belt.     

中天山科克苏河地区隆升剥蚀历史——来自(U-Th)/He年龄的制约

天山是中亚造山带重要组成部分,其中-新生代构造热演化及隆升剥露史研究是认识中亚造山带构造变形过程与机制的关键.本文应用磷灰石（U-Th） /He技术重建中天山南缘科克苏河地区中-新生代构造热演化及隆升剥蚀过程.磷灰石（U-Th） /He数据综合解释及热演化史模拟表明该地区至少存在晚白垩世、早中新世、晚中新世3期快速隆升剥蚀事件,起始时间分别为～90 Ma、～13 Ma及～5 Ma,且这3期隆升剥蚀事件在整个天山地区具有广泛的可对比性.相对于磷灰石裂变径迹,磷灰石（U-Th）/He年龄记录了中天山南缘地质演化史中更新和更近的热信息,即中天山在晚中新世（～5 Ma）快速隆升剥蚀,其剥蚀速率为～0.47 mm·a-1,剥蚀厚度为～2300 m.总体上,中天山科克苏地区隆升剥蚀起始时间从天山造山带向昭苏盆地（由南向北）逐渐变老,表明了中天山南缘隆升剥蚀存在不均一性,并发生了多期揭顶剥蚀事件.     

“平、剖面三维联动编辑”的实现途径

基于对平、剖面三维联动编辑的概念、动因的探讨及相关研究成果的认识,提出了平、剖面三维联动编辑的几何原理与实现途径,如:地质曲面的表达、基于等高线的曲面构建、剖面图的构建、以及平面图与剖面图的联动修改方法。并对三维地质建模的需求、矿产资源勘探应提交的三维地质模型、三维地质建模的数据标准以及广义的三维联动编辑等问题进行了延伸讨论。认为平、剖面三维联动编辑可能成为三维建模软件推广应用中的"杀手级应用"。     

龙门山陆内俯冲带形成机制探讨

本文分析了龙门山陆内俯冲带两侧岩石圈的强度结构特征及在侧向力作用下所发生的变形过程。盆地岩石圈中高强度层厚而紧凑,显示了较好的整体高强度性;造山带岩石圈上地壳具高强度,其下为低强度层。在侧向挤压力的作用下,变形主要发生于造山带一侧,最可能的变形方式是其脆性上地壳出现倾向后陆的逆冲断层,盆地岩石圈沿此断层俯冲,挤压其下部的低强度层,使之发生韧性增厚变形。     

阿联酋东鲁卜哈利盆地白垩系Mishrif组碳酸盐岩储层孔隙特征

上白垩统Mishirif组是阿联酋东鲁卜哈利盆地主要的产油层,目前对Mishrif-1段和Mishrif-3段储层孔隙特征差异的研究较为薄弱.在岩心描述、薄片鉴定、气测、压汞及核磁共振测试的基础上,对Mishrif组储层储集空间、孔隙结构进行了系统研究,明确了储层的相控特征以及Mishrif-1段和Mishrif-3段...