Virtual Field Geologic Trip System     

Jian Wang  Linfu Xue  Xiaojun Zhou 《世界地质(英文版)》2003,6(2)

Virtual Field Geologic Trip System (VFGTS) constructed by the technique of visualization can efficiently present geologic field information and widely used in the field of geologic education. This paper introduces the developing thinking of VFGTS and discusses the main implement processes. Building VFGTS mainly includes systemically gathering of field geological data, the building of virtual geological world, and displaying of virtual geologic world and human-computer interaction.  相似文献   

洱海近区非潮汐重力变化的研究     

翦大西  孙少安  刘力 《大地测量与地球动力学》1993,(3)

本文给出了洱海水体变化对局部重力场影响的解析式和量级,并且将理论结果与实测的水文、流动重力及定点重力分析结果作了比较,结果表明:影响的程度因距洱海的距离而异。在台站重力测量中,由水体变化产生的干扰淹没在零漂之中(约占每日零漂量的2％),潮汐主频段上没有明显的干扰信号;而对流动重力测量,在水体变化大的情况下,部分测点所产生的变化可以达到10×10~(-8)m/s~2。  相似文献   

Deepwater Ventilation and Stratification in the Neogene South China Sea     

李前裕赵泉鸿  钟广法翦知湣 田军成鑫荣  汪品先陈木宏 《中国地质大学学报(英文版)》2007,18(2):95-108

Combined data of physical property, benthic foraminifera, and stable isotopes from ODP Sites 1148, 1146, and 1143 are used to discuss deep water evolution in the South China Sea (SCS) since the Early Miocene. The results indicate that 3 lithostratigraphic units, respectively corresponding to 21-17 Ma, 15-10 Ma, and 10-5 Ma with positive red parameter (a*) marking the red brown sediment color represent 3 periods of deep water ventilation. The first 2 periods show a closer link to contemporary production of the Antarctic Bottom Water (AABW) and Northern Component Water (NCW), indicating a free connection of deep waters between the SCS and the open ocean before 10 Ma. After 10 Ma, red parameter dropped but stayed higher than the modern value (a*=0), the CaCO3 percentage difference between Site 1148 from a lower deepwater setting and Site 1146 from an upper deepwater setting enlarged significantly, and benthic species which prefer oxygen-rich bottom conditions dramatically decreased. Coupled with a major negative excursion of benthic δ13C at ~10 Ma, these parameters may denote a weakening in the control of the SCS deep water by the open ocean. Probably they mark the birth of a local deep water due to shallow waterways or rise of sill depths during the course of sea basin closing from south to east by the west-moving Philippine Arc after the end of SCS seafloor spreading at 16-15 Ma. However, it took another 5 Ma before the dissolved oxygen approached close to the modern level. Although the oxygen level continued to stabilize, several Pacific Bottom Water (PBW) and Pacific Deep Water (PDW) marker species rapidly increased since ~6 Ma, followed by a dramatic escalation in planktonic fragmentation which indicates high dissolution especially after ~5 Ma. The period of 5-3 Ma saw the strongest stratified deepwater in the then SCS, as indicated by up to 40% CaCO3 difference between Sites 1148 and 1146. Apart from a strengthening PDW as a result of global cooling and ice cap buildup on northern high latitudes, a deepening sea basin due to stronger subduction eastward may also have triggered the influx of more corrosive waters from the deep western Pacific. Since 3 Ma, the evolution of the SCS deep water entered a modern phase, as characterized by relative stable 10% CaCO3 difference between the two sites and increase in infaunal benthic species which prefer a low oxygenated environment. Thesubsequent reduction of PBW and PDW marker species at about 1.2 Ma and 0.9 Ma and another significant negative excursion of benthic δ13C to a Neogene minimum at ~0.9 Ma together convey a clear message that the PBW largely disappeared and the PDW considerably weakened in the Mid-Pleistocene SCS. Therefore, the true modern mode SCS deep water started to form only during the "Mid-Pleistocene climatic transition" probably due to the rise of sill depths under the Bashi Strait.  相似文献   

基于组件MapObjects的查询信息系统的设计与实现   总被引：10，自引：0，他引：10  

何宗宜  刘健 《测绘通报》2007,(5):30-33,37

讨论如何运用GIS组件MapObjects与面向对象的可视化编程语言Visual Basic 6.0相结合这一开发模式,进行应用型地理信息系统的二次开发。对系统开发方式的选择、系统总体框架、系统开发结构和系统数据库设计等作较为深入的论述。以武汉大学查询信息系统为例,具体探讨系统的设计与系统部分功能的实现。  相似文献   

非等间隔灰色GM(1,1)模型在沉降数据分析中的应用   总被引：10，自引：3，他引：7  

李斌  朱健 《测绘科学》2007,32(4):52-55

本文用灰色系统理论的非等间隔模型GM(1,1)对西安市朱雀大厦周边建筑物及地表沉降观测数据进行了建模、分析和预测,并且与传统的回归模型拟合结果进行了比较,比较的结果验证了该灰色模型在建筑物及地表沉降变形分析中的实用性、正确性和有效性。  相似文献   

Petrology and Geochronology of Granulites from the McKaskle Hills, Eastern Amery Ice Shelf, Antarctica, and Implications for the Evolution of the Prydz Belt   总被引：8，自引：0，他引：8  

Liu  Xiaochun; Zhao  Yue; Zhao  Guochun; Jian  Ping; Xu  Gang 《Journal of Petrology》2007,48(8):1443-1470

A combined petrological and geochronological study was carriedout on mafic granulites and associated felsic gneisses fromthe McKaskle Hills, eastern Amery Ice Shelf, East Antarctica.Garnet-bearing mafic granulites exhibit reaction textures andexsolution textures that indicate two-stage metamorphic evolution.Thermobarometric estimates from matrix and symplectite assemblagesyield peak and retrograde P–T conditions of 9·0–9·5kbar and 880–950°C and 6·6–7·2kbar and 700–750°C, respectively. Similar but slightlyscattered peak P–T estimates of 7·9–10·1kbar and 820–980°C are obtained from the core compositionsof minerals from felsic para- and orthogneisses. Evidence forthe prograde history is provided by muscovite inclusions ingarnet from a paragneiss. Sensitive high-resolution ion microprobeU–Pb zircon dating reveals an evolutionary history forthe granulites, including a mafic and felsic igneous intrusionat 1174–1019 Ma, sedimentation after 932–916 Ma,and a high-grade metamorphism at 533–529 Ma. In contrast,Sm–Nd mineral–whole-rock dating mainly yields asingle age population at 500 Ma. This suggests that the McKaskleHills form part of the Prydz Belt, and that the relatively highpeak P–T conditions and a decompression-dominated P–Tpath for the rocks resulted from a single Cambrian metamorphiccycle, rather than two distinct metamorphic events as formerlyinferred for the granulites from Prydz Bay. The age data alsoindicate that the Precambrian history of the McKaskle Hillsis not only distinct from that of the early Neoproterozoic terranein the northern Prince Charles Mountains, but also differentfrom that of other parts of the Prydz Belt. The existence ofmultiple basement terranes, together with considerable crustalthickening followed by tectonic uplift and unroofing indicatedby the clockwise P–T–t evolution, suggests thatthe Prydz Belt may represent a collisional orogen that resultedin the assembly of Gondwana during the Cambrian period. KEY WORDS: Mesoproterozoic basement; Cambrian metamorphism; P–T path; Prydz Belt; East Antarctica  相似文献   

含交叉断层的复杂地质体3维建模算法研究     

李静静  陈健  卢新明  王小花 《测绘科学技术学报》2007,24(3):219-222

在矿井生产中,出现交叉断层的区域往往是地质构造非常复杂的地方,也是危险高发的区域.对含交叉断层的3维地质建模的算法进行了研究.其主要思想是分别建立岩层和断层的TIN模型,以断层交线作为约束条件,进行带约束三角剖分,从而建立起交叉断层模型.这将有利于矿山的工程管理,减少危险的发生,作为后续采矿生产的依据.  相似文献   

A Fast Reprojection Method for MODIS Products with Sinusoidal Projection     

Jian Li  Shengbo Chen  Wenhan Qin  Juliana Useya  Zhijun Zhen  Yufei Wang 《Journal of the Indian Society of Remote Sensing》2018,46(10):1563-1567

  相似文献   

利用NMF算法确定ZTD格网产品空间分辨率     

刘志平  朱丹彤  王潜心  王坚 《测绘通报》2018,(5):6-10,19

GGOS Atmosphere发布的ZTD格网产品得到了广泛应用,然而该产品空间分辨率的确定缺乏足够依据。本文分析了GGOS ZWD、ZHD产品与ECMWF发布的PWV、SP产品之间的强相关性,计算了不同空间分辨率格网产品的经纬向梯度分组概率;同时利用所提出的基于随机学习速率矩阵的改进NMF算法提取了不同空间分辨率格网产品的特征维数,进而确定了ZTD格网产品的最佳空间分辨率、固有特征维数,并提供了一种数据压缩发布方案。  相似文献   

可见光波段灰度熵和热红外亮温差的沙尘遥感判识   总被引：1，自引：0，他引：1  

李彬  卢士庆  孙小龙  高健  孟翔晨  赵悦晨  吕迪波 《遥感学报》2018,22(4):647-657

沙尘作为对流层气溶胶的主要成分,对气候系统有许多影响;同时,作为环境污染物,对人类健康危害也很大。沙尘天气一般在春季爆发,对中国北方大部分区域的生产和生活有较大影响。以往针对沙尘遥感监测人们开展了许多研究,取得了一定的效果。但对于一些云和沙尘混合的复杂状况,传统方法识别效果较差,几乎不能有效识别出沙尘。采用葵花8号(Himawari-8)卫星数据,提出一种针对性的识别方法。引入了0.46μm和0.51μm反射率差值RDI,统计发现该指数在一定范围内可以表现出沙尘连续性特征,并有效地将中高云和大部分地表与沙尘区分开来。碎积云的RDI值分布与沙尘的较为相似,为此进一步引入了灰度熵方法来滤除。例举了3次沙尘过程的判识结果,并结合地面观测数据进行了验证。其中对2017年5月4日沙尘的地面验证表明,位于云沙混合区的27个站中有22个站的地面观测与判识相一致。对于一些复杂条件下的沙尘,该方法是对分裂窗亮温差的有效补充。  相似文献