协同多时相波谱特征的不透水面信息级联提取     

帅艳民  马现伟  曲歌  邵聪颖  刘涛  刘守民  黄华兵  谷玲霄  拉提帕•吐尔汗江  梁继  李玲 《地球信息科学学报》2021,23(1):171-186

不透水面作为反应城市表征变化和区域城镇化的重要技术指标,其位置、图斑大小、空间分布等信息在地表水热循环和能量平衡等领域被广泛需求。传统方法大都基于单一时相信息提取不透水面,而忽略多时相所蕴含的丰富信息。因此,本文提出多时相信息融合的不透水面级联提取方法,利用Landsat-8 OLI遥感影像分析归一化植被指数（Normalized Difference Vegetation Index, NDVI）、改进的归一化水体指数（Modified Normalized Difference Water Index, MNDWI）和归一化建筑指数（Normalized Difference Building Index, NDBI）年内时序变化特点和典型地物间多时相波谱曲线的协同特征,并归纳不透水面多时相变化规律;再根据先验知识所获取的有效地表信息,进行多时相分级提取不透水面信息。此外,基于实地考察数据和同期2 m GF-1遥感影像屏幕数字化生成30 m不透水面图斑,进行精度验证、分析和对比单时相、四季相及多时相3种时序情况下的提取精度。结果表明：单时相提取不透水面总精度最低,四季相提取精度优于单时相,而多时相提取精度最高（精度可达93.66%,Kappa系数为0.81）。本方法在偏远城镇不透水面的有效识别中显露潜在优势,可为不透水面提取方法融合时序波谱特征提供新思路。  相似文献   

华南亚热带中部山地垂直植被带表土孢粉散布规律与气候相关性     

全晓文  黄康有  水坤春  李宏卫  谢德豪  左锦堂  岑彩凤  郑卓 《热带地理》2022,42(10):1597-1608

孢粉学分析是古生态与古气候定量重建的重要指标之一,建立现代表土孢粉与植被之间的定量关系是利用地层孢粉准确解释古生态与古气候变化的前提条件。基于华南亚热带中部山地垂直植被带采集的113个现代表土和苔藓孢粉样品,采用典型对应分析方法（Canonical Correspondence Analysis, CCA）,探讨研究区不同海拔表土孢粉种类散布规律与气候因子之间的关系。主要得出以下结论：1）华南亚热带中部地区现代表土孢粉组合中乔木类以壳斗科栲属、常绿栎属、松属、杉木属和大戟科等种类占绝对优势,草本植物花粉以禾本科、蒿属、菊科和莎草科为主,蕨类孢子以三缝孢子、芒萁属、水龙骨科和单缝孢子为主。2）研究区低海拔至高海拔的孢粉组合呈现以下变化规律：低海拔地区（0~702 m）孢粉组合以栲属、常绿栎属、松属、野桐属、枫香属、茜草科以及禾本科花粉为主;中海拔（703~1 299 m）山坡的优势孢粉为栲属、杉木属、松属和常绿栎属;高海拔地区（1 300~1 600 m）以栲属、常绿栎属、水青冈属、杜鹃花科以及松属花粉最为丰富,表土孢粉组合变化过程与现代植被群落优势种类有较好的一致性。3）CCA分析结果显示,控制研究区域主要表土孢粉分布的气候因子为年均降雨量（MAP）、最热月降水（Mpwa）和最热月温度（Mtwa）;松属、杉木属、栲属、常绿栎属、山茶科、水青冈属和落叶栎属等高百分比含量的花粉所对应的气候特征较为明显。4）低海拔地区的优势种属栲属、常绿栎属等以及相对高海拔的松属、杉木属和水青冈属等能较好地反映气候因子对植被空间分布的影响。因此,文章揭示了华南亚热带中部地区表土孢粉在垂直植被带上具有明显差异,孢粉散布规律可能与研究区植被组成、生境、花粉形态与传播媒介等因素有关,能为利用化石孢粉数据进行古生态与古气候定量重建提供参考资料。  相似文献   

Remnants of the amalgamation of the east and west Cathaysia blocks revealed by a short-period dense nodal array     

《地学前缘(英文版)》2023,14(1):101482

The Cathaysia block located at the southeast South China block (SCB) is considered formed by the amalgamation of the east and west Cathaysia blocks along the Gaoyao–Huilai and Zhenghe–Dapu deep faults (here referred as GHF and ZDF, respectively). Although the extension of the ZDF to the northeast, which represents the amalgamation of the two sub-blocks has been confirmed, the development of the GHF to the southwest remains to be verified. To better constrain the detailed deep structure beneath the southwest Cathaysia, which hold great significance for revealing the evolution of the SCB, a linear seismic array with 331 nodal geophones was deployed across the Sanshui basin (SSB). Combining with the regional 10 permanent stations (PA), we obtained two profiles with teleseismic P-wave receiver function stacking. The most obvious feature in our results is the ascending Moho towards the coastal area, which is consistent with the passive margin continental and extensional tectonic setting. The stacking profile from the dense nodal array (DNA) shows that the Moho is offset beneath the transition zone of the Nanling orogeny and SSB. We deduce that this offset may be casued by the deep extension of the GHF, which represents the remnants of the amalgamation of the Cathaysia block. From the other evidences, we infer that the widespread and early erupted felsic magmas in the SSB may have resulted from lithospheric materials that were squeezed out to the surface. The relative higher Bouguer gravity and heat flow support the consolidation of magmas and the residual warm state in the shallow crustal scale beneath the SSB. The sporadic basaltic magmas in the middle SSB may have a close relation to deep extension of the GHF, which serves as a channel for upwelling hot materials.  相似文献   

Micrometallogeny and hydrothermal fluid evolution of the Iju porphyry Cu deposit,NW Kerman,Iran: Evidence from fluid inclusions,Laser Raman spectroscopy,and SO isotope systematics     

《Chemie der Erde / Geochemistry》2023,83(2):125956

The Iju Cu porphyry is located in the NW part of the Kerman Magmatic Copper Belt (KMCB). It is related to a ~ 9 Ma granodiorite porphyry intrusion, with three main stages of hydrothermal activity. The homogenization temperatures for the fluid inclusions are in the ranges of 200–494 °C, and their salinities vary from 4.0 to 42.8 wt% NaCl equiv., which are typical magmatic-hydrothermal fluids. The δ³⁴S values of sulfides range from −0.4 to +3.2 ‰ (V-CDT), and the δ³⁴S values of anhydrite samples range from +11.6 to +16.8 ‰. The δ³⁴S values of sulfides show a narrow range, implying a homogeneous sulfur source. The oxygen isotopic composition of hydrothermal water in equilibrium with quartz samples ranges from +3.4 to +6.0 ‰ (V-SMOW) consistent with the hydrothermal fluids having a magmatic signature, but diluted with meteoric waters in the main mineralizing stage. The most important factors responsible for metal precipitation in the Iju porphyry deposit are fluid boiling, oxygen fugacity decrease and cooling followed by dilution with meteoric water. The primary fluids of the Iju Cu deposit are characterized by relatively high temperature and moderate salinity, and are CO₂-rich, indicating a typical post-collisional porphyry system.  相似文献   

Mine waste water self-purification (arsenic) in neutral hydrogeochemical ecosystem: A case study from V-Ti-Fe mine tailings     

《Chemie der Erde / Geochemistry》2023,83(2):125947

The fate of the arsenic (As) under neutral hydrogeochemical conditions in the mining ecosystem has attracted increasing concern, as the ecological restoration of As provides a possibility for safe use of mine water. However, successful cases are still inadequately reported worldwide. Therefore, to investigate the As-behavior in the mine tailings ecosystem, a study of the Wanniangou tailings pond (regional largest V-Ti-Fe mine tailings pond, Sichuan province, China) and the downstream (Rehe River) was conducted. It involves hydro-geochemistry, mineralogy, biogeochemistry, and the Geographically Weighted Regression model (GWR). The results reveal that: (1) the pH range of the mine water is 6.32 to 7.21. The chemical weathering of tailings resulted in an abnormal As concentration in water (e.g., transport pipe wastewater 76.5 μg L⁻¹, the outlet of tailings pond 28.4 μg L⁻¹), and it declines to the national water quality guideline (<10 μg L⁻¹) after 2.59 km from the pond outlet. (2) Although sulfide oxidation boosts As migration in the tailings, As ecological refixation is promoted by tailings particle percolation, river sediment absorption, and aquatic plant uptake. The As refixation behaviors vary spatially, corresponding with the diversity of precipitation and absorption. Besides, Manganese (oxides or/and hydroxides) is conducive to As coprecipitation in the neutral hydrogeochemical environment. (3) The site selection of the V-Ti-Fe mine tailings pond with a downstream longer than 3 km creates a toxic metals self-restoration buffer zone, which could relieve the contamination probability and make the mining wastewater re-utilization feasible.  相似文献   

Petrographic and mineral chemistry investigation of the high-grade chrysotile asbestos-bearing Zvishavane Ultramafic Complex,south central Zimbabwe     

《Chemie der Erde / Geochemistry》2023,83(2):125950

The Zvishavane Ultramafic Complex (ZUC) in the south central part of the Zimbabwe craton is comprised of coarse-grained serpentinites, metadunites and metagabbros and hosts Africa's largest reserves, and largest mine, of high-grade chrysotile asbestos. Magnesiohornblende, actinolite, plagioclase (An_0.6–41.9), augite, diopside and clinozoisite constitute the mineralogy of the ZUC. Forsteritic olivine (>Fo₉₀) was altered to form chrysotile and antigorite minerals, although some primary olivines are preserved. Contents of Al₂O₃ range from <1 to >2.5 wt% at TiO₂ values of <0.7 wt% consistent with an island arc setting for the ZUC that originated from tholeiitic magmas. The Zvishavane Ultramafic Complex was metamorphosed at relatively high temperatures (542-779 °C) and low pressures (1.2-2kbars), consistent with contact metamorphism. Intrusion of several granitic batholiths relatively close to the ZUC likely triggered hydrothermal fluid migration which metamorphosed the ZUC. The associated asbestos deposits likely formed during hydrothermal circulation events. Zoned amphiboles, the occurrence of magnesiohornblende and actinolite, as well as cross-cutting serpentine veins are consistent with at least two stages of alteration and/or metamorphism of the ZUC. The lack of a thrust contact between the ZUC and its country rocks is consistent with the ZUC having intruded into the host Zvishavane Gneiss Complex and possibly acted as a feeder to the nearby Mberengwa greenstone belt (MGB). However, the occurrence of near end-member forsteritic olivine, the presence of zoned amphiboles, and faulting within the ZUC are all suggestive of an ophiolitic origin although forsteritic olivines also occur in intrusive layered complexes. Metamorphism of the ZUC, ascribed to intrusion of multiple batholiths and possibly the MGB, likely led to the formation of ZUC chrysotile asbestos deposits.  相似文献   

井下甚宽频带地震仪总体设计研究进展          下载免费PDF全文

李丽  罗新恒  杨大克  薛兵  郑重  吕金水 《地震科学进展》2022,(7):294-301

针对2000 m深井观测的国家需求,应用 “解构与重构” 设计思路,共性赋能技术与地震技术深度融合的设计方法,对井下甚宽频带地震仪进行创新性总体设计;电磁兼容性、环境适应性与可靠性设计等定型技术设计;结构、功能与外壳的设计。测试和试运行结果表明,新研制的井下甚宽频带地震仪完全达到设计指标。   相似文献   

长距离数据传输抗干扰技术研究进展          下载免费PDF全文

潘飞儒  赵圣麟  李丽  关作金  叶海峰 《地震科学进展》2022,(7):302-308

研究高温高压高湿环境下,长距离数据传输抗干扰技术,设计有效的数据传输方式,组建稳定高效的传输系统是井下甚宽频带地震仪研制项目的重要环节。长距离数据传输抗干扰技术研究进展主要包括:低功耗、小型化、高分辨率、大动态范围的数据采集核心模块,传输抗干扰技术,数据传输协议及高精度授时等。   相似文献   

井下甚宽频带地震仪可靠性测试研究进展          下载免费PDF全文

陈洁  罗敏哲  李丽  赵圣麟  庞锦标 《地震科学进展》2022,(7):316-321

井下甚宽频带地震仪可靠性测试研究进展主要包括:可靠性测试平台（试验观测井、地下比测实验室、高温高压试验平台、盐雾实验平台）的搭建、室内外仪器可靠性和环境适应性验证两部分。   相似文献   

内蒙古额尔古纳红水泉地区奥陶系乌宾敖包组沉积时代及物源区分析:碎屑锆石U-Pb年代学,Lu-Hf同位素地球化学证据     

黄泽涛  梁新权  梁细荣  宋天骄  王策 《地球化学》2022,51(1):98-122

选取内蒙古额尔古纳红水泉地区奥陶系乌宾敖包组石英砂岩进行碎屑锆石U-Pb年龄、原位Lu-Hf同位素研究,尝试限定该地层形成时代及碎屑物质来源,并探讨其沉积大地构造环境。结果显示,采自该地层的2个砂岩样品中的碎屑锆石多数发育典型的岩浆振荡生长环带,呈自形–半自形且具有较高的Th/U值(0.12~1.63),均暗示它们多数为岩浆成因。结合微量元素特征及稀土元素配分模式图,认为碎屑锆石寄主岩石应为花岗质杂岩体。2个砂岩样品具有相似的年龄和Hf同位素组成,锆石年龄分布大致可分为3个主要年龄区间:(1)440~540 Ma,主峰值年龄约为492 Ma和506 Ma,次峰值年龄为447 Ma;ε_Hf(t)值介于?2.77~+11.73之间,Hf的两阶段模式年龄为680~1636 Ma;(2)750~950 Ma,主峰值年龄为805 Ma,次峰值年龄为825 Ma和961 Ma;ε_Hf(t)值介于?1.14~+11.43之间,Hf的两阶段模式年龄为1100~1824 Ma;(3)1700~2000 Ma,峰值年龄为1787 Ma;ε_Hf(t)值介于?9.18~?2.75之间,Hf的两阶段模式年龄为2682~3016 Ma。所有样品碎屑锆石ε_Hf(t)值为?9.18~+11.73,Hf的两阶段模式年龄为680~3016 Ma,大部分锆石的Hf同位素组成集中于球粒陨石与亏损地幔标准线之间,表明沉积物源以早古生代和新元古代新增生地壳物质为主,同时存在少量中元古代晚期古老地壳物质的活化改造。结合前人已报道的邻区相关岩体年代学及地球化学资料,研究区乌宾敖包组的沉积时代不早于晚奥陶世,沉积物主要来自额尔古纳和兴安地块的近缘碎屑物,其形成与早古生代时期古亚洲洋演化过程中额尔古纳与兴安地块碰撞拼贴以及随后的伸展垮塌相关。  相似文献