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太行山构造岩浆带K－Ar法同位素年龄分析 总被引：4，自引：0，他引：4
５００余个同位素测年数据的统计特征表明，目前所取得的Ｋ－Ａｒ法同位素年龄的统计峰值不能直接用来表示地质体的形成年龄，而是记录了区域造山抬升剥蚀的历史。利用不同地质样品的冷却年龄峰值，可以定性地估算区域隆升速率和隆升高度。在这个前提下，太行山构造岩浆带在中生代时期的抬升速率为０．４２１～０．２５３ｍｍ／ａ，隆升高度为８７９９～５２８８ｍ。 相似文献
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芙蓉洞的次生化学沉积物 总被引：26，自引：15，他引：11
芙蓉洞是一个大型石灰岩洞穴,形成于第四纪中更新世。在成为化石洞穴的发展阶段中,发生过大规模的崩塌。其后１６～２０万年以来,约在四个主要时期形成了极其丰富的次生化学沉积物,其矿物组成主要是方解石和石膏。本文着重介绍和讨论了芙蓉洞的特色沉积——池水沉积和非重力水沉积的性质和特征,以及洞穴化学沉积物的形成年代和形成阶段。 相似文献
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青藏高原的隆起与海洋锶同位素组成的演化 总被引：5，自引：2，他引：3
近年来,随着构造隆升驱动气候变化假说的提出,青藏高原的隆起受到越来越多的关注,并将之与大陆化学风化速率及海洋锶同位素的演化紧密联系。围绕青藏高原的隆升及其环境与气候效应,对海洋锶同位素组成的演化特征及其影响因素的较为全面而详细的论述表明:将青藏高原的隆升与全球气候变化、大陆化学风化速率及海洋锶同位素组成的演化相联系,也许是解决目前关于海洋锶同位素组成的演化及其物源问题的重要手段,根据海洋锶同位素的演化历史来研究全球气候变化规律及青藏高原的构造演化历史将是本研究领域的重点。 相似文献
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青藏高原的隆起与海洋锶同位素组成的演化 总被引：3，自引：1，他引：2
近年来,随着构造隆升驱动气候变化假说的提出,青藏高原的隆起受到越来越多的关注,并将之与大陆化学风化速率及海洋锶同位素的演化紧密联系.围绕青藏高原的隆升及其环境与气候效应,对海洋锶同位素组成的演化特征及其影响因素的较为全面而详细的论述表明:将青藏高原的隆升与全球气候变化、大陆化学风化速率及海洋锶同位素组成的演化相联系,也许是解决目前关于海洋锶同位素组成的演化及其物源问题的重要手段,根据海洋锶同位素的演化历史来研究全球气候变化规律及青藏高原的构造演化历史将是本研究领域的重点. 相似文献
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洞穴沉积物的环境记录研究进展 总被引：2，自引：0，他引：2
云贵高原有着独特的地理环境,其气候变迁与青藏高原这一特殊的高海拔,低续度的隆升地块有重要关系,洞穴化学沉积物是响应环境的地质记录档案,通过对它蕴藏的古气候信息的解译,可以反演过去的气候变化,本文侧重介绍了沿穴次生化学沉积物研究近年来取得的最新成晨及其研究现状,并利用其在古代环境研究中的优点,来讨论青藏高原的抬 对西南地欧环境变化产生的屏蔽效应的可能性。 相似文献
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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
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
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稳定同位素是在洞穴次生化学沉积物(以下简称洞穴沉积物)中研究最为深入且应用最为广泛的环境替代指标之一.但随着对洞穴系统现代过程监测工作的开展,发现洞穴系统中稳定同位素的演化是一个相当复杂的过程,需要进一步的工作阐明其真实涵义.因此,研究它在洞穴系统中的信号传递有重要意义. 相似文献
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Coastal uplift rate at Matanzas (Cuba) inferred from MIS5e phreatic overgrowths on speleothems 
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下载免费PDF全文 Jo De Waele Ilenia M. D'Angeli Nicola Tisato Paola Tuccimei Michele Soligo Joaquín Ginés Angel Ginés Joan J. Fornós Igor M. Villa Esteban R. Grau González Stefano M. Bernasconi Tomaso R. R. Bontognali 《地学学报》2017,29(2):98-105
Many morphological elements in Cuba's landscape (e.g. marine terraces, tidal notches) demonstrate that coastal uplift has taken place, but the rate at which this occurs is not known. Carbonate phreatic overgrowths on speleothems have been found in a cave in Central North Cuba, ~1 km from the present coastline at 16 m asl. They form exceptional and unique mushroom‐shaped speleothems and balconies decorating the walls of the rooms. These phreatic overgrowths on speleothems (POS) formed at the oscillating air–water interface in sea‐level controlled anchialine lakes. U/Th dating of these overgrowths suggests ages that are compatible with the Marine Isotope Stage 5e (i.e. 130–115 ka). These POS have fixed this sea‐level highstand and demonstrate that this part of Cuba has been subjected to a much lower uplift rate than previously reported, that is, less than 0.1 mm/year since the last interglacial. 相似文献
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广西巴马县水晶宫洞穴沉积物特征及其沉积环境 总被引：4，自引：3，他引：1
巴马县水晶宫洞内次生化学沉积物景观丰富,类型多样,有石钟乳、石幔、石瀑布、石笋、石柱、石盾等特色景观;尤其是近期仍在发育的洞顶鹅管、卷曲石、石花等是国内外较为罕见的洞穴奇景。据沉积物的沉积类型、物质成分、沉积序次及测年等资料研究表明,水晶宫洞穴沉积物形成于晚第三纪以来。晚第三纪和第四纪早更新世早期,洞内沉积主要为外源水携带的硅质岩、砂岩类砾石沉积形成的钙华砾石层。早更新世中期—中更新世气候温暖湿润,是水晶宫洞穴主要景观的形成期,沉积物景观宏大而壮观,230Th-U系测年得出其分别形成于100～35万年前。晚更新世早期12.5～9万年的末次间冰期主要为温暖气候环境,洞内仅有少量的石笋沉积,且极少保存;9万年后气候环境发生突变,更不利沉积物发育和保存;自4万年后气候环境开始表现为温暖湿润,化学沉积活跃,洞穴沉积物主要由高约50～150 cm的纯白色石笋群和钟乳石组成,为洞穴奇景的形成期,230Th-U系测年得出其分别形成于40 ka BP和7 500 a BP以及1 450 a BP。晚更新世晚期以来形成的洞穴沉积物景观,不仅为水晶宫提供了丰富的旅游资源和价值,同时也为广西重建古气候环境提供了重要的信息载体。 相似文献
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Oxygen and carbon isotopic systematics of aragonite speleothems and water in Furong Cave, Chongqing, China 总被引：10，自引：0，他引：10
Ting-Yong Li Chuan-Chou Shen Hong-Chun Li Jun-Yun Li Sheng-Rong Song Chris D.-J. Lin Liping Zhou Ming-Yang Ye Shi-You Xie 《Geochimica et cosmochimica acta》2011,75(15):4140-4156
To understand oxygen and carbon stable isotopic characteristics of aragonite stalagmites and evaluate their applicability to paleoclimate, the isotopic compositions of active and fossil aragonite speleothems and water samples from an in situ multi-year (October 2005-July 2010) monitoring program in Furong Cave located in Chongqing of China have been examined. The observations during October 2005-June 2007 show that the meteoric water is well mixed in the overlying 300-500-m bedrock aquifer, reflected by relatively constant δ18O, ±0.11-0.14‰ (1σ), of drip waters in the cave, which represents the annual status of rainfall water. Active cave aragonite speleothems are at oxygen isotopic equilibrium with drip water and their δ18O values capture the surface-water oxygen isotopic signal. Aragonite-to-calcite transformation since the last glaciation is not noticeable in Furong stalagmites. Our multi-year field experiment approves that aragonite stalagmite δ18O records in this cave are suitable for paleoclimate reconstruction. With high U, 0.5-7.2 ppm, and low Th, 20-1270 ppt, the Furong aragonite stalagmites provide very precise chronology (as good as ±20s yrs (2σ)) of the climatic variations since the last deglaciation. The synchroneity of Chinese stalagmite δ18O records at the transition into the Bølling-Allerød (t-BA) and the Younger Dryas from Furong, Hulu and Dongge Caves supports the fidelity of the reconstructed East Asian monsoon evolution. However, the Furong record shows that the cold Older Dryas (OD) occurred at 14.0 thousand years ago, agreeing with Greenland ice core δ18O records but ∼200 yrs younger than that in the Hulu record. The OD age discrepancy between Chinese caves can be attributable to different regionally climatic/environmental conditions or chronological uncertainty of stalagmite proxy records, which is limited by changes in growth rate and subsampling intervals in absolute dating. Seasonal dissolved inorganic carbon δ13C variations of 2-3‰ in the drip water and 5-7‰ in the pool and spring waters are likely attributed to variable degrees of CO2 degassing in winter and summer. The variable δ13C values of active deposits from −11‰ to 0‰ could be caused by kinetically mediated CO2 degassing processes. The complicated nature of pre-deposition kinetic isotopic fractionation processes for carbon isotopes in speleothems at Furong Cave require further study before they can be interpreted in a paleoclimatic or paleoenvironmental context. 相似文献
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Speleothems occurring in some caves of the carbonate Dinarides line all channel surfaces, and have been deposited from meteoric waters under phreatic conditions. Such phreatic speleothemic deposition modifies common experience (l) that meteoric phreatic conditions cause dissolutional widening of cave voids, and (2) that speleothems imply vadose conditions. The phreatic speleothems described here postdate an early polygenetic evolution of the cave voids, and predate the last, vadose stage. They were likely produced during the late/postglacial warming period, when dissolved carbonate was amply supplied, and when there was much water available for saturation of underground voids. Phreatic speleothems may be used as a tool for time correlation of internal deposits, both within one cave and within a karst region. They indicate an important stage in the history of the ground-water regime of an area. In general, phreatic speleothems help in better understanding of the development of subterranean voids and related karst/palaeokarst. 相似文献
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重庆丰都雪玉洞群包括羊子洞、雪玉洞和水鸣洞,西南大学的研究团队从2008年开始对雪玉洞群开展了系统的现代过程监测,以了解洞穴系统气候和环境信息的传输、转化和记录过程。通过对雪玉洞洞穴内外的大气、植被、土壤、基岩、滴水和洞穴沉积物等的动态监测,研究了碳酸盐沉积过程的水化学指标变化,揭示了现代洞穴滴水的影响因素和变化过程,以及碳酸盐沉积物对现代气候环境变化的响应,也为古气候的定量化研究提供了基础支撑。现代过程监测记录表明:雪玉洞CO2主要来源于上覆土壤,其季节变化受降水的影响较大;在短时间尺度上受到游客旅游活动的影响明显,但幅度远远小于自然过程引起的变化。雪玉洞内次生沉积物的沉积速率具有明显的旱季、雨季特征,不同滴水点下方沉积物的沉积速率变化较大。雪玉洞群三个洞穴的石笋古环境记录研究表明,本区石笋的230Th/232Th比值较适合高精度铀系测年;部分石笋沉积速率较快,平均沉积速率达到0.25 mm·a?1,可以开展高分辨率的气候和环境变化研究。羊子洞YZ1石笋的年龄范围在116~3 ka B.P.之间（平均测年精度2σ,269年）,覆盖了整个末次冰期,δ18O和δ13C的变化曲线和东亚季风区的其他记录具有明显的一致性。同位素测试的时间分辨率平均为88年,成功记录了一些百年－千年尺度的气候突变事件,如Heinrich事件、7.2 ka事件、小冰期等。在精确年代学的基础上,雪玉洞群石笋具有重建高分辨率气候环境变化的潜力。 相似文献
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采用国际上最先进的高精度热电离质谱测年技术,测定了南京汤山葫芦洞钙板和石笋的年龄。并根据洞穴碳酸盐相与洞穴文化堆积层的地层关系,确定南京直立人化石时代在距今50万年左右。 相似文献
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The cave bear was a prominent member of the Upper Pleistocene fauna in Eurasia. While breakthroughs were recently achieved with respect to its phylogeny using ancient DNA techniques, it is still challenging to date cave bear fossils beyond the radiocarbon age range. Without an accurate and precise chronological framework, however, key questions regarding the palaeoecology cannot be addressed, such as the extent to which large climate swings during the last glacial affected the habitat and possibly even conditioned the final extinction of this mammal. Key to constraining the age of cave bear fossils older than the lower limit of radiocarbon dating is to date interlayered speleothems using 230Th/U. Here we report new results from one such site in the Eastern European Alps (Schwabenreith Cave), which yielded the highest density of bones of cave bear (Ursus spelaeus eremus). Although dating of the flowstones overlying this fossiliferous succession was partly compromised by diagenetic alteration, the 230Th/U dates indicate that the bear hibernated in this cave after about 113 ka and before about 109 ka. This time interval coincides with the equivalent of Greenland Stadial 25, suggesting possible climate control on the cave bear's habitat and behaviour. © 2019 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd 相似文献
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为提高公众对洞穴旅游资源非使用价值的重视程度,以世界自然遗产地芙蓉洞为研究对象,采用单边界二分式条件价值法,以到芙蓉洞景区旅游的游客、重庆市民为调查对象,对芙蓉洞洞穴旅游资源的非使用价值进行评估。其结果表明:芙蓉洞洞穴旅游资源非使用价值的平均支付意愿为330.49元,非使用价值总额为229.82亿元,远大于其门票收入;芙蓉洞洞穴旅游资源非使用价值的平均支付意愿大小与被调查者对芙蓉洞非使用价值的了解程度、婚姻状况、年龄、职业、年收入、文化程度、人均出游花销显著相关。今后应加强对芙蓉洞非使用价值的认知,通过多种渠道宣传芙蓉洞的非使用价值,多方合力,共同保护芙蓉洞洞穴旅游资源。 相似文献
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本文对周口店新发现距今11～1.9万年的东岭子洞穴堆积物进行了成因研究,认为该套堆积物并非全属岩溶堆积物,其中也有风成黄土沉积。应用古地磁、热发光及铀系法等年代学方法测定,认为这套堆积为距今11～1.9万年间沉积,弥补了周口店地区近5万年的晚更新世洞穴地层空缺,是一个含有丰富地质事件的晚更新世洞穴地层剖面。 相似文献