连通域标识法在FMI图像溶洞信息定量拾取中的应用          下载免费PDF全文

闫建平  梁强  李尊芝  耿斌  寇小攀  扈勇 《地球物理学报》2016,59(12):4759-4770

溶蚀孔洞在碳酸盐岩储层中是重要的流体储集空间,研究成像测井(FMI)图像孔洞连通域标记及信息定量拾取很有意义.全井眼微电阻率成像测井(FMI)经数据处理后可得到全井壁高分辨率的彩色图像,经图像灰度化、中值滤波处理后,通过阈值分割得到能够反映井壁溶蚀孔洞特征的二值图像,孔洞表现为黑色暗斑.基于等价对处理的图像连通域标记算法具有快速、不重复标记的优点,利用该算法,可准确地从二值图像中标记溶蚀孔洞连通域,进而可对每个连通域进行目标信息拾取,包括孔洞尺寸、连通域面积、圆度等.利用反映溶蚀孔洞发育程度的面孔率曲线对图像进行分层,在此基础上可拾取每一层段溶蚀孔洞面孔率、分选系数及溶洞密度值的分布等非均质信息,能够定量地评价溶蚀孔洞发育、非均质性强的碳酸盐岩储层,也是FMI图像应用于岩石孔洞结构信息定量表征新的尝试.  相似文献   

Shared microsporidian profiles between an obligate (Niphargus) and facultative subterranean amphipod population (Gammarus) at sympatry provide indications for underground transmission pathways     

《Limnologica》2016

Only sparse knowledge exists on amphipod-infecting microsporidians in subterranean waters. Here, we DNA barcoded two sympatric amphipod populations (obligate subterranean Niphargus schellenbergi, facultative Gammarus fossarum) and their microsporidian parasites. Parasite prevalence was assessed by diagnostic PCR assays. Overall prevalence was 82.7 %. Both amphipod populations shared all four identified parasite species (Nosema granulosis, Microsporidium sp. I, Orthosomella sp., Microsporidium sp. BPAR3). Hence, we postulate underground transmission pathways of microsporidians mediated by subterranean amphipod hosts.  相似文献   

北京石花洞石笋微层层面有机物质的形成时间及机理初探   总被引：12，自引：4，他引：8       下载免费PDF全文

班凤梅  潘根兴  王新中 《第四纪研究》2005,25(2):265-268

通过对北京石花洞滴水水溶性有机碳(DOC)近一个水文年的观测,发现不同点滴水DOC浓度均表现出明显的季节性变化,7月中旬均有一个大的主峰出现。初步说明中国北方石笋微层的层面物质沉积于7月雨季,主要来源于大的雨量对土壤中有机质的淋溶;洞穴顶板较薄的滴水点在5月和8月有明显的DOC次峰,可能与石笋亚年层形成有关。  相似文献   

Insights into Wasatch fault vertical slip rates using the age of sediments in Timpanogos Cave, Utah     

Alan L. Mayo  Jiri Bruthans  David Tingey  Jaroslav Kadlec  Steve Nelson 《Quaternary Research》2009,72(2):275-283

Timpanogos Cave, located near the Wasatch fault, is about 357 m above the American Fork River. Fluvial cave sediments and an interbedded carbonate flowstone yield a paleomagnetic and U–Th depositional age of 350 to 780 ka. Fault vertical slip rates, inferred from calculated river downcutting rates, range between 1.02 and 0.46 mm yr^− 1. These slip rates are in the range of the 0–12 Ma Wasatch Range exhumation rate ( 0.5–0.7 mm yr^− 1), suggesting that the long-term vertical slip rate remained stable through mid-Pleistocene time. However, the late Pleistocene (0–250 ka) decelerated slip rate ( 0.2–0.3 mm yr^− 1) and the accelerated Holocene slip rate ( 1.2 mm yr^− 1) are consistent with episodic fault activity. Assuming that the late Pleistocene vertical slip rate represents an episodic slowing of fault movement and the long-term (0–12 Ma) average vertical slip rate, including the late Pleistocene and Holocene, should be  0.6 mm yr^− 1, there is a net late Pleistocene vertical slip deficit of  50–75 m. The Holocene and late Pleistocene slip rates may be typical for episodes of accelerated and slowed fault movement, respectively. The calculated late Pleistocene slip deficit may mean that the current accelerated Wasatch fault slip rate will extend well into the future.  相似文献   

芙蓉洞洞穴水离子浓度和元素比值变化特征及其环境意义   总被引：5，自引：3，他引：2  

衣成城  李廷勇  李俊云  王建力  向晓晶  白莹  唐亮亮  谢世友 《中国岩溶》2011,30(2):200-207

通过对芙蓉洞2006年3月—2009年2月期间泉水和洞穴滴水、池水的地球化学指标监测,结合当地的器测数据,初步认为洞穴滴水的Sr2+、Ca2+、Mg2+浓度及其比值既取决于环境降水和温度的变化,也受到上覆岩土作用的影响。芙蓉洞外山上的6#泉水Ca2+平均浓度为45.81mg/L,洞内1#、3#滴水Ca2+的平均浓度64.59mg/L,2#和4#池水中由于Ca2+沉积,浓度下降到24.74mg/L,下降了大约61.7%。Mg2+和Sr2+的浓度在泉水、滴水和池水中的变化规律与Ca2+基本一致。各种水体中Cl-的浓度变化幅度较小,平均浓度为1.72±0.2mg/L。岩溶水与基岩作用时间长短以及运移过程中Ca2+的前期沉积作用对各元素与离子含量变化具有重要作用。旱季Ca2+的前期沉积作用和雨季基岩的溶蚀及雨水的稀释作用主导着岩溶水中Mg/Ca与Sr/Ca的变化,这些指标能对干旱和洪涝等极端气候事件做出响应。   相似文献   

重庆芙蓉洞崩塌作用及其环境效应   总被引：2，自引：2，他引：0  

黄保健 《中国岩溶》2011,30(1):105-112

利用洞穴调查和各类次生化学沉积物同位素测年技术等方法,对芙蓉洞内崩塌物进行研究。结果表明芙蓉洞内崩塌物规模巨大,为多期次崩塌作用的产物,分别形成于大于35万年、35～20万年间、10～2.6万年间、2.5万年后及旅游开放后的1995、2000、2003、2008年,既有洞顶围岩的规模性崩塌,也有洞顶石钟乳的崩落和洞底石笋、石柱的倒塌,分别起因于地壳抬升背景下洞内水流下切使原先浮力消失引起洞顶围岩地应力失衡、洞顶石钟乳不断联合使重量超过联合体-洞顶围岩接触面的临界结合力和洞底石笋、石柱受崩落的钟乳石砸中或强地震引发。崩塌作用引起了洞腔的规模性扩大、钟乳石景观和旅游设施的破坏、被迫改变游览线路等环境效应。针对芙蓉洞崩塌特点,提出了洞穴旅游开发的一些建议。   相似文献   

A framework for karst ecohydrology   总被引：7，自引：0，他引：7  

Ognjen Bonacci  Tanja Pipan  David C. Culver 《Environmental Geology》2009,56(5):891-900

Ecohydrology can be defined as the science of integrating hydrological and biological processes over varied spatial and temporal scales. There exists in karst a strong and direct interaction between the circulation and storage of groundwater and surface water. These fluxes in turn affect the spatial distribution of organisms in these habitats. Because of the fact that the appearance, storage and circulation of water in karstified areas is significantly different from other more homogenous and isotropic terrains, karst ecohydrology should develop original methods and approaches. At the same time, traditional approaches are also very useful. Large karst underground geomorphological patterns occur in many sizes and varieties, ranging from a few meters long or deep to very large, the deepest being deeper than 1 km and longer than hundreds of kilometres. In this article, special attention is paid to ecohydrological functions of karst underground features (caves, pits, conduits, etc.), which play a crucial dual role in (1) hydrology and hydrogeology of water circulation and storage and (2) ecology of many rare and endangered species. Differences in morphology, hydrology, hydrogeology and climate have resulted in a range of different environments, which provide the opportunity for the coexistence of different species. The role of the epikarst and vadose zones, as well as caves in ecohydrological processes, is discussed. The importance of the flood factor in karst ecology is analysed. The aim of this article is to move forward the discussion among different disciplines to promote and develop a conceptual framework for karst ecohydrology.  相似文献   

贵州荔波1200年来石笋高分辨率的古气候环境记录   总被引：4，自引：1，他引：3  

张美良  朱晓燕  程海  林玉石  覃嘉铭  冉景丞  王华  何师意 《地球学报》2009,30(6):831-840

通过笔者对荔波龙泉洞L2石笋进行高精度的ICP-MS-230Th测年和碳、氧同位素分析, 建立了荔波地区1200 a BP 来高分辨率的古气候变化的时间序列。研究结果表明, 荔波地区1200 a BP以来石笋记录的季风气候经历了1200~1100 a BP(暖)、1100~940 a BP (冷)、940~840 a BP(暖)、840~700 a BP(冷)、700~450 a BP(暖)、450~300 a BP(冷)、300~200 a BP(暖)以及200~70 a BP(冷)等8个阶段百年尺度的干湿、冷暖波动, 并在这些百年尺度的波动上又叠加了一系列数十年尺度的气候变化。石笋记录揭示了1200 a以来东亚季风气候的不稳定性, 呈百年尺度(Gleissberg)的周期性变化。这些气候变化事件, 与冰芯记录极为相似, 反映低纬度地区百年尺度石笋记录的季风气候变化与高纬度及北极地区的气候变化具有极好的相关性, 反映百年尺度石笋记录的季风降水主要受太阳辐射驱动、控制, 而东亚季风的降水事件(或干旱事件)与太阳的辐射强度密切相关。石笋记录的百年尺度季风降水事件对于认识现代气候系统变化以及对未来十年—百年尺度的气候预测和演化的驱动机制, 具有重要的科学意义。  相似文献   

Reef margin collapse, gully formation and filling within the Permian Capitan Reef: Carlsbad Caverns, New Mexico, USA     

Gill M. Harwood  & Alan C. Kendall 《Sedimentology》1999,46(3):443-461

An area of reef margin collapse, gully formation and gully fill sedimentation has been identified and mapped within Left Hand Tunnel, Carlsbad Caverns. It demonstrates that the Capitan Reef did not, at all times, form an unbroken border to the Delaware Basin. Geopetally arranged sediments within cavities from sponge–algal framestones of the reef show that the in situ reef today has a 10° basinwards structural dip. Similar dips in adjacent back-reef sediments, previously considered depositional, probably also have a structural origin. Reoriented geopetal structures have also allowed the identification of a 200-m-wide, 25-m-deep gully within the reef, which has been filled by large (some  >15 m), randomly orientated and, in places, overturned blocks and boulders, surrounded by finer reef rubble, breccias and grainstones. Block supply continued throughout gully filling, implying that spalling of reef blocks was a longer term process and was not a by-product of the formation of the gully. Gully initiation was probably the result of a reef front collapse, with a continued instability of the gully bordering reef facies demonstrated by their incipient brecciation and by faults containing synsedimentary fills. Gully filling probably occurred during reef growth, and younger reef has prograded over the gully fill. Blocks contain truncated former aragonite botryoidal cements, indicating early aragonite growth within the in situ reef. In contrast, former high-magnesian calcite rind cements post-date sedimentation within the gully. The morphology of cavern passages is controlled by reef facies variation, with narrower passages cut into the in situ reef and wider passages within the gully fill. Gully fills may also constitute more permeable zones in the subsurface.  相似文献   

京西鸡毛洞的发现及其意义     

吕金波  孙永华  李铁英 《地质通报》1999,18(2)

新发现的鸡毛洞属岩溶洞穴,位于北京市房山区佛子庄乡北窖村。据洞中现存的文物资料记载,早在唐朝（公元６７０～７３３年）已经是当地居民经常活动和栖息的场所。该洞穴不仅在岩溶地质学和考古学方面有重要的研究价值,而且具有建成一个新的旅游景点的良好前景  相似文献