Research on the Fitting Algorithms of Almanac Parameters for Navigation Satellites     

Liu-cheng Chen  Xiao-gong Hu  Chun-hao Han  Jin-ping Chen 《Chinese Astronomy and Astrophysics》2009

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鲁西寒武系第三统张夏组附枝菌与附枝菌微生物灰岩特征研究   总被引：6，自引：0，他引：6  

韩作振  陈吉涛  张晓蕾  于学峰 《地质学报》2009,83(8):1097-1103

本文通过大比例尺野外测量及镜下观察,对鲁西寒武系第三统张夏组的附枝菌与附枝菌微生物灰岩特征进行了详细研究。附枝菌是一种树枝状蓝细菌,一般向上生长扩展,形成灌木状附枝菌群落,生长于附枝菌微生物丘内部。而在微生物丘的外部边缘,附枝菌群落呈半闭合的房室状,与肾状菌十分相似。房室状附枝菌群落可能是在微生物丘外部边缘受局部高能微环境（如水流、波浪等）的影响形成的。在其形成后,其保存状态则是由附枝菌的钙化作用及早期成岩作用决定。由于附枝菌构成其微生物岩的生长骨架,且该微生物岩不具备清晰的中型构造,故可称其为附枝菌格架岩,作为对微生物岩分类命名的又一补充。附枝菌格架岩一般生长于台地边缘或台地外部斜坡环境,其生长过程受水动力条件、阳光照射及海水清澈度等影响。  相似文献   

河北承德大庙黑山钒钛磁体矿床地质特征与成因探讨   总被引：8，自引：1，他引：7  

孙静  杜维河  王德忠  李健  徐国新  韩玉丑 《地质学报》2009,83(9):1344-1364

河北承德大庙黑山铁矿床位于大庙斜长岩体南部边缘,红石砬—大庙深断裂附近北侧。矿区内主要岩类为斜长岩,根据蚀变作用可分为钠黝帘石化斜长岩、绿泥石化斜长岩及混染斜长岩等,前者广泛分布于矿区内,后二者常构成铁矿的直接围岩。黑山铁矿苏长岩体与铁矿体有成因联系,主要受近东西向压扭性断层和龙潭沟—岔沟压扭性断裂带构造控制,分布于黑山斜长岩体内。部分苏长岩体中有分异式浸染矿体,在苏长岩接触带及其围岩中的矿体则为贯入式矿体。苏长岩体根据其特征和共生组合,可划分为两个岩石系列：①苏长岩岩石系列（苏长岩类型岩体、含橄苏长岩苏长岩类型岩体）;②二长岩苏长岩岩石系列（二长岩苏长岩类型岩体、二长岩橄榄苏长岩类型岩体）。矿石结构主要为自形—半自形晶粒状结构、格状熔离结构、海绵陨铁结构。矿石构造有致密块状构造、浸染状构造。矿石金属矿物主要为含钒钛磁铁矿（含量3%～60%）、钛铁矿（含量2%～19%）、含钒磁铁矿（含量7%～27%）,次有少量含钴黄铁矿、黄铜矿。脉石矿物主要为绿泥石（含量7%～33%）,次为斜长石（0%～45%）,及其它少量矿物。黑山的矿源苏长岩和中国及世界同类岩石有显著不同,Si、Al、Fe、Ti、P、Na、K含量高,Ca、Mg含量低,这类岩体为形成铁磷矿床提供了物质来源。本区斜长岩、矿源苏长岩铁矿床和铁磷矿床的氧同位素组成δ18O限于一个很窄的变化范围,反映了它们的物质来源和成因类型的同一性。黑山苏长岩、伟晶苏长岩δ34S 为+1.3‰～+2.1‰,反映苏长岩浆来源于上地幔。黑山铁磷矿体经铁钛氧化物矿物对形成温度计计算得出生成温度为615~975℃,显示该岩浆矿床高温成矿特点。研究认为黑山铁矿主要①、②号铁矿体为岩浆贯入成矿。  相似文献   

Deep root of a continent-continent collision belt: Evidence from the Chinese Continental Scientific Drilling (CCSD) deep borehole in the Sulu ultrahigh-pressure (HP-UHP) metamorphic terrane, China   总被引：2，自引：0，他引：2  

Zhiqin Xu  Shaocheng Ji  Zeming Zhang  Qin Wang 《Tectonophysics》2009,475(2):204-219

The Chinese Continental Scientific Drilling (CCSD) deep borehole, which reached a depth of 5158 m in the Sulu ultrahigh-pressure (UHP) metamorphic terrane, provides a new window into the deep root of a continent-continent collision belt, and the tectonic processes by which supracrustal material is recycled into the mantle by subduction and then uplifted to the surface. Major research themes of the CCSD project were to: (1) determine the three-dimensional composition, structure and geophysical character of the deep root of this orogenic belt; (2) investigate the nature and timing of the UHP metamorphism; (3) investigate the processes of crust-mantle interaction involved in the formation and exhumation of the UHP rocks; (4) study the process of fluid circulation and mineralization during subduction and exhumation; (5) study the rheological properties of the various rocks during subduction and exhumation; (6) develop and refine dynamic models for deep subduction and exhumation of crustal rocks, and (7) establish a long-term, natural laboratory for the study of present-day crustal dynamics (e.g., stress, strain, fluid activity). The CCSD has developed precise oriented profiles of the main borehole in terms of lithology, geochemistry, oxygen isotopes, zircon SHRIMP U-Pb ages, ⁴⁰Ar-³⁹Ar ages, deformation, rheology, mineralization, physical properties of the rocks, petrophysical logs, seismic reflections and underground fluids. The present paper summarizes the integrated research results of this project, especially the new findings concerning the deep root of a continent-continent collision.  相似文献   

超声提取-固相萃取小柱净化-气相色谱法测定土壤中14种有机氯农药   总被引：7，自引：7，他引：0  

刘文长  陶文靖  程丽娅  余兴  田旻  黄勤  李胜生 《岩矿测试》2009,28(6):541-544

对土壤中14种有机氯农药的超声提取技术和磺化、固相萃取小柱两种净化方法进行系统研究。结果表明,超声提取节省提取时间,提高分析效率;磺化法和固相萃取小柱法都有净化作用,但磺化法使样品中的艾氏剂、狄氏剂和异狄氏剂全部损失;固相萃取小柱净化当丙酮-正己烷淋洗液体积比为1∶9、淋洗液收集8 mL时回收率>90%,干扰最小。方法检出限为0.63~2.59μg/kg,精密度(RSD,n=7)为1.17%~14.66%,基体加标平均回收率为82.78%~106.94%。方法用于生态地球化学调查评价批量土壤样品的实际分析,检测结果满足评价工作需要。  相似文献   

鲁西隆起北侧博兴洼陷新生界碎屑重矿物记录及其对构造古地理环境的指示   总被引：1，自引：0，他引：1       下载免费PDF全文

许承武  李忠  韩登林  韩银学  彭守涛  刘嘉庆 《地质科学》2009,44(1):257-267

对鲁西隆起北侧博兴洼陷新生界碎屑重矿物组份和稳定性组合的研究发现：古近纪孔店组沉积期、沙河街组四段沉积晚期和沙河街组二段沉积期金红石、电气石、锆石和白钛矿等稳定碎屑莺矿物占优势,指示盆-山的构造古地理分异较弱;沙四段沉积早期、沙三段和沙一段沉积期绿帘石、榍石等不稳定碎屑重矿物占优势,表明构造古地理分异强烈.新近纪馆陶组稳定重矿物自下而上逐渐占据优势,表明该时期构造活动逐渐趋缓;明化镇组自下而上不稳定重矿物逐渐占优势,指示构造活动逐渐加强.根据砂岩中自生矿物赤（褐）铁矿的分析,认为其含量较高的孔店组、沙四段、沙段沉积期气候干旱,而含量较低的沙四段沉积末期一沙二段沉积期气候湿润;新近纪里赤（褐）铁矿含量向上增大,可能指示气候干旱程度加剧.  相似文献   

塔中地区志留系碎屑锆石测年及其地质意义   总被引：1，自引：0，他引：1       下载免费PDF全文

邬光辉  张宝收  苏文  汪海  席勤 《地质科学》2009,44(3):1025-1035

志留系是塔里木盆地第一套砂岩储层广泛分布的沉积盖层,其沉积来源与成因对志留纪构造演化及周边造山带的研究具有重要意义。塔中地区3个志留系样品的碎屑锆石LA?ICP?MS U?Pb定年研究表明,志留系具有比较集中的二期物源年龄：南华纪中期、古元古代中期。碎屑锆石测定的年龄表明塔中志留系物源均来自前寒武纪,塔中东部源区方向的塔南隆起基底在奥陶纪已隆升成为蚀源区。大量的新元古代中期锆石年龄表明塔里木板块在新元古代时期可能与Rodinia超大陆具有相似的聚合与裂解演化史。  相似文献   

Determination of the degree 120 time-variable gravity field in the Sichuan-Yunnan region using Slepian functions and terrestrial measurements          下载免费PDF全文

Jiancheng Han  Shi Chen  Zhaohui Chen  Hongyan Lu  Weimin Xu 《地震科学（英文版）》2021,34(3):211-221

The terrestrial time-variable gravity measurements are characterized by a high signal-to-noise ratio and sensitivity to the sources of mass change in the Earth's crust. These gravity data have many applications, such as surface deformation, groundwater storage changes, and mass migration before and after earthquakes. Based on repeated terrestrial gravity measurements at 198 gravity stations in the Sichuan-Yunnan region (SYR) from 2015 to 2017, we determine a time series of degree 120 gravity fields using the localized spherical harmonic (Slepian) basis functions. Our results show that adopting the first 6 Slepian basis functions is sufficient for effective localized Slepian modeling in the SYR. The differences between two gravity campaigns at the same time of year show an obvious correlation with tectonic features. The degree 120 timevariable gravity models presented in this paper will benefit the study of the regional mass migration inside the crust of the SYR and supplement the existing geophysical models for the China Seismic Experimental Site.  相似文献   

New approaches for archaeal genome-guided cultivation     

Wang  Yinzhao  Kamagata  Yoichi  Li  Meng  Han  Feifei  Wang  Fengping  Xiao  Xiang 《中国科学:地球科学(英文版)》2021,64(10):1658-1673

Archaea, one of the three domains of life along with Bacteria and Eukarya, contains ancient life forms such as methanogen that are observed today on Earth, and one lineage Asgard archaea is also considered the closest ancestor of Eukarya.Recently, with the development of interdisciplinary studies from Earth and Life sciences, archaeal organisms are considered to play pivotal roles in geochemical cycling in nature. However, our understanding of the attributes, origin and evolution, geochemical and ecological functions of Archaea is hampered by the scarcity of archaeal isolates, which has represented a challenge to researchers for the last 40 years. Cultivation-independent sequencing and phylogenomic analyses have demonstrated a considerable diversity of Archaea with more than 20 novel phyla. However, only four archaeal phyla have cultured representatives, leaving large gaps in our knowledge of the metabolic capabilities and ecological functions of the majority of archaeal strains identified exclusively by DNA sequencing. In this review, we summarize the discovery and development of archaeal research, highlight the knowledge gap between uncultured and cultured archaeal microbes, and call on the importance of devoting greater research efforts to archaeal cultivation. Finally, we outlined new ideas and strategic approaches, namely,(1)genome-based methods,(2) microbial network information-based methods,(3) genome-scale model-guided methods, and(4)machine learning methods, to enable the cultivation of uncultivated archaeal microbes using accumulated high-throughput sequencing data.  相似文献   

北京环线建设驱动的土地利用变化遥感检测与分析   总被引：6，自引：0，他引：6  

戴芹  马建文  陈雪 《遥感学报》2005,9(3):314-322

近年来,北京市的环线建设大大改进了北京的交通状况,促进了环线周边的商业发展和房地产开发的繁荣,同时也带来了环线周边地区的土地利用的变更。在“科技奥运”科技攻关项目和在研自然科学基金项目的支撑下,选择了1988,1994,2001和2003年5—6月份的TM数据,在影像经过几何校正和辐射归一化校正后对其应用高精度的自组织神经网络分类和利用高分辨率的航空照片验证;在分类数据和变更信息的基础上,采用了空间自相关分析模型、频率指数模型和潜力模型分别对北京各种用地类型的频率指数和建设用地的Moran系数和Geary系数,以及城市增长的潜力指她进行计算。一系列计算显示了环线驱动的北京市土地利用变化情况。结果表明:在环线建设的驱动下,北京市的建设用地围绕环线呈快速增长趋势;绿地面积在四环、五环的环线一带也呈增加趋势;城市增长潜力从四环到六环呈逐渐增大趋势。  相似文献