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201.
The research area is located in the western part of Sichuan basin as a Yangtze ecotope of Cathaysian Tethyan area. It is dominated by benthic fauna, including brachiopods, Fusulinids, corals, bivalves, foraminifers, ammonites, bryozoans,Crinoids and pleopods which are less common with traces of trilobites, stromatoporas, nautilus and sporopollens seen in one or two areas,which are obviously controlled by sedimentary environments and in accordance with sedimentary facies.Through the analysis of fossils and research on burial characteristics from middle Permian middleTriassic, based on the combination of the feature of fossils in time and space, seventeen communities are recognized, the coposition, construction and palaeoenvironment of each community are expounded. Study shows that different ecological type biocoenose are distributed in different locations, which are mainly represented by sessile benthic community in the main research area, composed of Mianzhu, Mianyang, Deyang and Santai and nektonic community in marginal areas in the research area subdivided into two parts: Areas around Guangyuan-Nanjiang-Tongjiang, located at the margins in the northeast of the research area, and areas around Wenchuan-Maoxian-Dayidafeishui situated at the western borders of the research area. According to the combination of communities with sedimentary characteristics,six kinds of biofacies have been recognized and described in the study area and biofacies pattern are established. Category,ecotype, typical community and sedimentary facies of each biofacies are elucidated in this paper. The subdivision and analysis of community are meaningful for the studies of paleoenvironment ,paleogeography and their evolutions,The research of biaofacies is important for the recovery of paleobiogeography and paleoplate tectonic characteristics. 相似文献
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根据宜昌站、汉口站和大通站的径流量数据,运用M-K检验和小波分析等方法,对1900年以来长江流域径流量的趋势和周期变化进行分析,探究径流量变化对厄尔尼诺?南方涛动(ENSO)和太平洋年代际振荡(PDO)的响应。结果表明:1900 年以来长江流域径流量呈显著的减少趋势,并具有2~8 a的年际周期变化和14~17 a的年代际周期变化。流域径流量与ENSO具有相同的2~8 a周期变化,在El Ni?o发生期,径流量较低,在La Ni?a发生期,径流量较高。14~17 a的周期变化与PDO相关,在暖位相期径流量偏少,在冷位相期径流量偏多。PDO影响着ENSO和径流量之间的相关性,在暖位相期,El Ni?o对径流量的影响增强,在冷位相期,La Ni?a对径流量的影响增强。因此,在分析和预测流域径流量长时间尺度上的变化时要综合考虑ENSO和PDO的影响。 相似文献
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GPS Solutions - Carrier phase ambiguity resolution over long baselines is challenging in BDS data processing. This is partially due to the variations of the hardware biases in BDS code signals and... 相似文献
206.
宫同伦 《地球科学与环境学报》1991,(1)
本文用动力成矿观点对小秦岭金矿田富矿体的形成提出了新的解释,对本区的动力成矿特点作了较详细的说明。文中联系到地壳演化的不同阶段对金矿的富化过程进行了较深入的讨论,并提出了新的成矿系列。笔者以基础地质、大地构造和同位素年龄资料为依据对小秦岭金矿田含金石英脉的成因提出了与前人不同的新观点,认为它是晋宁晚期岩浆期后热液矿床。 相似文献
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对东风盐场9个站位卤水中由藻类植物产生的可溶性糖浓度的变化规律及其与海盐产量和质量之间的关系进行了研究。结果表明,各站位可溶性糖含量的变化范围为0.7-124.3mg/L,以6月份最高,2月份最低;卤水中可溶性糖在111mg/L-215mg/L范围内,结晶盐的产量随卤水中可溶性糖含量的增加而提高,但同时降低了NaCl的含量,并增加了可溶性杂质及水分的含量,从而降低了盐质。初始可溶性糖浓度为111mg/L、137mg/L、160mg/L、193mg/L和215mg/L的25.4°Be’的卤水,在日照下实验12天,其对应结晶盐的NaCl含量分别为91.66%、90.63%、90.48%、90.23%和88.46%,可溶性杂质的含量分别为3.05%、3.32%、3.33%和4.54%。 相似文献
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210.
Xiaopeng Gong Shengfeng Gu Yidong Lou Fu Zheng Maorong Ge Jingnan Liu 《Journal of Geodesy》2018,92(7):797-809
Global navigation satellite systems (GNSS) are acting as an indispensable tool for geodetic research and global monitoring of the Earth, and they have been rapidly developed over the past few years with abundant GNSS networks, modern constellations, and significant improvement in mathematic models of data processing. However, due to the increasing number of satellites and stations, the computational efficiency becomes a key issue and it could hamper the further development of GNSS applications. In this contribution, this problem is overcome from the aspects of both dense linear algebra algorithms and GNSS processing strategy. First, in order to fully explore the power of modern microprocessors, the square root information filter solution based on the blocked QR factorization employing as many matrix–matrix operations as possible is introduced. In addition, the algorithm complexity of GNSS data processing is further decreased by centralizing the carrier-phase observations and ambiguity parameters, as well as performing the real-time ambiguity resolution and elimination. Based on the QR factorization of the simulated matrix, we can conclude that compared to unblocked QR factorization, the blocked QR factorization can greatly improve processing efficiency with a magnitude of nearly two orders on a personal computer with four 3.30 GHz cores. Then, with 82 globally distributed stations, the processing efficiency is further validated in multi-GNSS (GPS/BDS/Galileo) satellite clock estimation. The results suggest that it will take about 31.38 s per epoch for the unblocked method. While, without any loss of accuracy, it only takes 0.50 and 0.31 s for our new algorithm per epoch for float and fixed clock solutions, respectively. 相似文献