安达曼海东部台缘阶地中新世生物礁演化特征及其古环境响应

新近纪以来,在大陆边缘以及火山基底隆起等构造背景下,安达曼海域广泛分布生物礁碳酸盐。为了更好地了解安达曼海域的构造演化以及区域古环境特征,通过高分辨率地震剖面,将台地边缘地层划分为5个地震层序。在建立的地震层序格架下,探讨了区域中新世生物礁演化模式及发育控制因素。研究认为安达曼海域东部台缘阶地中新世生物礁生长发育以及空间展布形态主要受中新世时期构造作用所形成的地势形态和海平面升降等因素联合控制。安达曼海中新世经历了裂谷期至弧后走滑拉分期,且伴随着海平面的上升。南部实皆断裂造成的东高西低的地势形态为东部阶地生物礁碳酸盐发育提供了有利场所,次级断裂造成了生物礁东西分割的格局,而海平面的稳定上升使得生物礁稳定生长。     

基于BIM的室内空间信息表达与管理方法

目前,BIM中室内信息通常只在二维视图中进行管理,而不能在三维视图下很好地表达,这对于BIM在建筑信息管理中的使用是不便的,因此,把室内信息从二维视图迁移到三维视图中进行管理非常有必要.本文以Revit中的房间信息为例,提出一种基于Revit二次开发的方法,能够在不影响模型使用的情况下把二维视图中的室内信息迁移到三维视图进行展示和管理.结果表明,这种方法操作方便,便于室内信息的查询、修改等后期管理工作,解决了Revit中室内信息在二维视图与三维视图信息分离的问题.     

Spatial distribution of archaeological sites in lakeshore of Chaohu Lake in China based on GIS

There are about 19 Neolithic Age sites and 120 Shang-Zhou dynasties sites in the western lakeshore of Chaohu Lake, Anhui Province, China. Based on sites data, topographic data, drainage maps, administrative maps and SPOT5 remote sensing data, spatial analysis methods were introduced into the archaeology of Chaohu Lake Basin with Geographic Information System (GIS). The spatial analysis methods include: 1) Point Density Analysis with density model to acquire the shift of the sites; 2) Distance Analysis to reveal the spatial structure of the sites; 3) 3D Analysis based on Digital Elevation Model to get micro-geomorphologic features of the sites; and 4) Buffer Analysis to discover the relationship between the sites and rivers. The results indicate that the archaeological sites spread from the western lakeshore of Chaohu Lake gradually to the northwest, later to the south, and then symmetrically spread. Controlled by productive forces and other factors, ancient people preferred to reside in those places near water, or in plain and fertile land, which resulted in linear and decentralized distribution of the sites, and presented such disciplines as river valley directivity, terrace directivity and soil directivity. This paper indicates that the distribution of archaeological sites was influenced earlier by natural elements and later by human elements in the study period. The research is important for the integration of GIS and archaeology.     

用数值法模拟断裂对岩溶塌陷的控制

通过地下水动态变化资料,采用数值方法反求出水文地质参数,并建立断裂构造、地下水迳流和岩溶塌陷之间的关系。由于地下水位变化过程是表现不同地段地下迳流补给和不同输水能力的特性,同时也综合地反映了水文地质条件。按照地下水二维非均质各向异性非稳定运动规律,用有限单元法确定了旱季及雨季的参数,并对这些参数用多年资料作了校验。 通过模拟计算,发现了一条北西西向断裂的存在,它控制着区内地下迳流和岩溶塌陷的形成,塌陷主要沿着张扭性断裂的方向延伸,尤在断裂交汇部位为甚。塌陷于1982年发现,预测发生在离水源地大约1100米及1500米处的塌陷,已于1983年全部得以证实。 该例表明,预报塌陷规律是可能的,它对断裂构造分析,防止塌陷,保护环境均有重要意义。      

Petrogenesis of Permo-Triassic intrusive rocks in Northern Liaoning Province,NE China: implications for the closure of the eastern Paleo-Asian Ocean

ABSTRACT

The Changchun-Yanji belt recorded widespread Permo-Triassic magmatism, but their origins remain unclear, inhibiting a comprehensive understanding of the magmatic response to the final closure of the Paleo-Asian ocean in the eastern Central Asian Orogenic Belt (CAOB). Here, we present new geochronological, geochemical, and Hf isotopic data for the Permo-Triassic plutons from Northern Liaoning province, NE China. Combined the published ages with our new data, the Permo-Triassic magmatism in the eastern CAOB can be divided into five episodes: early Permian (293–274 Ma), middle–late Permian (270–257 Ma), latest late Permian–Middle Triassic (255–242 Ma), Late Triassic (240–215 Ma), and latest Late Triassic (209–200 Ma). The middle Permian and Late Triassic mafic plutons (i.e. ~266 Ma Mengjiagou gabbro–diorite, ~240 Ma Jiancaicun gabbro and ~224 Ma Shudetun gabbro-diorite) contain relatively high TFe₂O₃, MgO, Cr and Ni contents with positive ε_Hf(t) values (+1.2 to +7.2), suggesting a depleted mantle origin. These mafic rocks together with the coeval granitoids make up typical bimodal associations, suggesting that they were formed under an extensional environment. The conclusions are also supported by occurrence of A-type granites during 270–257 Ma and 240–215 Ma. By contrast, the granitoids of 255–242 Ma in the eastern CAOB, including the Jianshanzi (~251 Ma) and Daganhe (~242 Ma) monzogranites, show typical geochemical features of adakitic granites, with high Sr/Y ratios and negative ε_Hf(t) values (–8.6 to – 22.0), suggesting that the magmas were generated through partial melting of thickened ancient lower crust. Combined with previous studies, a four-stage tectonic evolution scenario was proposed: (1) active continental margin stage during 293–274 Ma; (2) continuing subduction resulted in the initiation collision, moderate crustal thickening, and slab break-off during 270–257 Ma; (3) final closure of the Paleo-Asian Ocean associated with continued crustal thickening occurred during 255–242 Ma; (4) lithospheric delamination in a post-collisional extensional environment occurred during 240–215 Ma.     

围填海疑点疑区监测技术方法

为严格围填海管控,迅速、准确和及时掌握用海情况,文章在明确围填海疑点疑区类型的基础上,概述其监测技术方法。研究结果表明:围填海疑点疑区的监测内容主要包括用海位置、面积、方式和类型等;主要利用卫星遥感、航空遥感和地面核查等技术手段;监测流程主要包括数据收集和处理、遥感变化图斑提取、疑点疑区图斑筛选以及疑点疑区核查4个步骤;监测成果可制作围填海疑点疑区核查报告和图集,为海洋行政主管部门提供执法和管理依据。     

一个改进的地球圈层差异旋转模型

地球自转速度在长期的减慢,而内核自转 又较其外部的地球部分转动快,这是由日 、月对地球的潮汐摩擦引起的同一动力学背景下导致的相关现象。通过能量守衡的定量分析 ,得出地球潮汐耗散能的11% 即可导致内核自转较其外部的地球部分自转快的结论。通过推 理比较和定量分析,提出了岩石圈层、主地幔圈层与内核三个圈层的差异旋转模型：岩石圈 自转速度<主地慢自转速度<内核自转速度。它可能是导致大陆向西飘移-板块构造及地磁产 生的重要机制之一。     

塔里木盆地碳酸盐岩油气聚集带

海相碳酸盐岩储层多类型及非均质性强的特点,决定了其油气聚集带与以往陆相盆地碎屑岩油气聚集带的控制因素有显著差异,碳酸盐岩的油气聚集并不是简单地受二级构造带的控制。通过分析塔里木盆地已发现碳酸盐岩油气藏,其储层发育受大气淡水风化淋滤作用、沉积作用及各种成岩作用、深部流体改造作用等因素的控制。据储层成因类型及其横向分布特征,将塔里木盆地碳酸盐岩油气聚集带划分为:不整合与古风化壳型、生物建造礁-滩型、白云岩内幕型及深部流体改造型。不同类型的碳酸盐岩油气聚集带主要分布于塔北隆起、塔中隆起及巴楚断隆等古隆起的不同部位。由于不同碳酸盐岩油气聚集带上储集层成因机制不同,导致其储集空间、储集性能、油气藏类型及分布等均有所不同。     

塔里木盆地塔中地区主要构造圈闭形成期分布及成藏意义

通过对塔中地区钻遇奥陶系的60余口井过井地震剖面的精细解释及地震反射截切—上超关系、沉积厚度变化分析,识别出最初形成于晚奥陶世—泥盆纪、石炭纪—早二叠世、早二叠世晚期及中、新生代的四期奥陶系内幕构造圈闭,以及最初形成于石炭纪—早二叠世、早二叠世晚期、晚二叠世、中—晚三叠世及早第三纪末以来的五期石炭系内幕构造圈闭;发现了塔中地区主要构造圈闭的首次形成期呈现由南向北逐渐变晚的总体趋势。构造圈闭形成与成藏配套综合分析表明,该区现今工业性油藏的主要成藏期为二叠纪—早三叠世,而中—晚三叠世及其以后所形成的构造圈闭不利于油藏的形成。认为塔中地区的主力烃源应该来自近邻的满加尔凹陷中—上奥陶统相当于黑土凹组—萨尔干组的层段。     

Subsurface old drainage detection and paleoenvironment analysis using spaceborne radar images in Alxa Plateau

For geological and environmental research in an arid area, a unique advantage of radar remote sensing is that radar wave can penetrate a certain layer of dry sand (a few centimeters to meters thick) to reach the buried bedrock. The penetration capability is able to reveal the subsurface geological structure and old drainage paths. Based on the analysis of SIR-A, SIR-B, SIR-C, Radarsat ScanSAR, Landsat MSS and Landsat TM images acquired on different dates and the investigations made in several field trips in Alxa Plateau of Inner Mongolia, a number of old river valley and lake basins buried by wind-blown sand were recognized. Two parallel old drainage systems in the north and middle of the study area are delineated. The study suggests that the moving sand belts mainly follow the old drainage courses. This study also establishes a preliminary drainage evolution model for an area of about 300 000 km2 since the Tertiary, and finds that the Alxa Plateau was once an area with many rivers and lakes with a warm and humid climate. The relief reversion caused by neotectonic movement since "Qinghai-Tibet movement" is also analyzed.