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1.
位于我国西北部的陇中盆地古近纪—新近纪(第三纪)地层出露较好,并且产出大量哺乳动物化石和植物化石,这为西北地区地层对比和古气候研究提供了良好材料。近几十年,众多学者在陇中盆地的各次级盆地(如西宁盆地、兰州盆地、临夏盆地等)开展了大量古生物学、生物地层学、磁性地层学和古气候学研究,为探讨陇中盆地的构造演化过程和气候演变过程提供了重要参考。本文对陇中盆地第三纪地层年代学和古气候研究已取得的进展进行了初步总结归纳,并提出了需要进一步研究的问题。  相似文献   

2.
安徽省地处华北、华南板块的交变地带,沉积单元和生物群落均非常复杂,自晚太古代以来的各时代地层发育较全并含有丰富的无脊椎动物、脊椎动物、植物化石和遗迹化石等.该省的古生物化石资源以分布广泛,类型众多,保存完好,科学意义重大为主要特征.本文重点探讨了安徽省古生物化石资源的分布特征、赋存特征及具有地方特色的古生物化石类型,对该省古生物化石资源的意义进行了初步评价,并对安徽省古生物化石资源的深入研究和合理开发利用的方向进行了述评.  相似文献   

3.
本文通过研究黄土高原西北—东南断面上三个剖面(渭南、洛川、九州台)末次间冰期以来的蜗牛化石记录,探讨了黄土-古土壤序列中蜗牛化石个体总数可能保存的古气候信息。研究表明,黄土-古土壤中蜗牛化石总数主要受控于研究区域保存条件(温度、降水及相联系的成壤强度)和生存条件(气候环境条件是否适宜蜗牛的生存)。保存条件为黄土高原南部蜗牛化石总数的主要影响因素,而黄土高原北部主要受生存条件控制,黄土高原中部则同时受两个因素的影响。基于洛川蜗牛化石总数的变化特征指出,~400 ka前后冰期气候状况存在明显差异,400 ka前的冰期更加适宜蜗牛的生存,此后洛川地区冰期蜗牛生存的气候环境条件不断恶化。本研究为利用蜗牛化石探讨黄土高原古气候、古环境变化提供了重要参考。  相似文献   

4.
阳逻砾石层及所含的大量的化石木,在古植物学、长江中游的古环境和古长江的形成与演化研究中具有重要意义。随着1984年阳逻被子化石木的发现,武汉阳逻化石木和阳逻砾石层就一直为学者们所关注。先后发现的硅化木化石已达200余件。在阳逻化石木鉴定、植物分类、植物生态学和古环境研究方面,在阳逻砾石层的时代及年龄、成因和物源等方面,做了大量的研究,发表了许多重要成果。然而,在一些基础问题研究上还存在着明显的分歧。建议:(1)在化石木的来源和砾石层物源分析方面,开展系统的沉积学、岩石学、矿物学以及地球化学的综合研究;(2)通过综合地层学研究,即生物地层(植物化石组合)、岩石地层(长江中游岩石地层对比)、地貌地层(长江中游地貌对比)和年代地层的综合对比,重点尝试宇生核元素、化石自旋共振(ESR)等测年技术的应用,以查明化石木和砾石层的形成时代;(3)加强化石木和砂砾层环境信息深入挖掘和综合对比分析。在查明化石木植物树种的组合全貌的基础上,通过古植被类型的恢复,特别是应加强化石木的显微结构分析,通过观察其构造特征和生长轮(木轮、年轮)的宽窄等信息,分析其古气候环境。  相似文献   

5.
王晶  徐海 《地球环境学报》2022,13(2):132-162
广泛分布的湖泊为连续沉积和保存历史时期多样化生物核酸分子提供了绝佳的自然档案。随着近年来古DNA提取和测序技术的进步以及组学技术的发展,利用湖泊沉积物古DNA重建古生态演化及其对气候变化和人类活动的差异性响应得到广泛而深入的研究。本文回顾了古DNA研究的历史背景、理论基础,以及湖泊沉积物古DNA保存的影响因素和生物信息学分析流程;重点评述了湖泊沉积物古DNA在揭示气候环境变化、生物多样性及流域生态系统演化、物种定殖与外来物种入侵、人类活动影响、环境生态功能基因演化及其在细胞器基因组和古生态时间序列分析研究中的诸多应用和进展。同时还介绍了当前研究面临的局限和挑战以及组学技术在古DNA研究中的发展概况,分析了当前研究尚存的不足,并展望了未来可能的努力方向。  相似文献   

6.
随着技术进步和多方位研究进展,第四纪古环境研究向着多元古环境替代指标、高分辨率古气候研究、气候变化的多种驱动因素等方面发展。文章总结了中国黄土古环境研究中的主要替代性指标,包括黄土磁化率、黄土粒度、植物硅酸体、孢粉组合、蜗牛化石、碳氧同位素和^10Be、黄土与古土壤。概述了当前对黄土—古土壤的时间标尺、末次冰期的短尺度气候事件以及东亚古季风变化机制的认识。  相似文献   

7.
<正> 在地球历史的研究中,地质学家经常改进技术,以掌握更加具体而定量的信息。这里论述的沉积物地质学,曾由于利用沉积学和经典古生物学以及微岩相和微化石研究的资料而得到了发展。最近又应用了物理技术。同位素丰度的分析最终为恢复古环境在地层学和地球化学领域方面带来了表层地质学所必不可少的东西,从而为阐明海洋和大陆物质间的关系作出了贡献。  相似文献   

8.
临海浙江翼龙及长尾雁荡鸟化石赋存于浙东小雄盆地晚白垩世形成的地层中。通过对比化石骨骼结构及生态习性,结合对地质背景、古地理、古生态环境及化石产地剖面岩性岩相、沉积构造、化石赋存状态、古植物及孢粉组合等研究认为:小雄盆地继承了早白垩世晚期永康期陆相盆地的构造格局,晚白垩世小雄早期,盆地间分布众多残存的湖泊沼泽,它们是翼龙类和鸟类最后的栖息地。受间歇性火山喷发影响,空落相火山碎屑物导致的湖泊萎缩及沼泽化、水体酸化、气候干热等是造成生活在湖泊沼泽周边和翱翔于天空中的翼龙及鸟类集群死亡的主要因素。小雄中晚期,浙东地区经历了较大规模的酸性岩浆喷溢及火山喷发堆积,为临海国家地质公园流纹岩地貌演化奠定了物质基础。  相似文献   

9.
火山灰的研究作为探讨古气候和古环境的一种手段,近十年来引起了国内外学者的广泛关注。气候学和古环境学的研究表明,火山喷发可以导致某一区域内短期的气候变化或者对冰期产生强烈影响。同时,火山灰层的成因机制决定了其空间分布的等时性和广泛性,因此,火山灰的地层学特征和精确定年,具有重要的地层对比意义。目前,全球各地已经开展了许多火山灰年代学与地层学的研究。在中国,尤其是东北地区,虽然有着丰富的火山资源,但是火山灰年代学与地层学的研究工作依然比较匮乏,本文简要回顾了一下中国东北、欧洲、新西兰、日本、俄罗斯等地区的火山灰研究工作,旨在为以后的研究提供一定的参考资料。  相似文献   

10.
火山灰的研究作为探讨古气候和古环境的一种手段,近十年来引起了国内外学者的广泛关注。气候学和古环境学的研究表明,火山喷发可以导致某一区域内短期的气候变化或者对冰期产生强烈影响。同时,火山灰层的成因机制决定了其空间分布的等时性和广泛性,因此,火山灰的地层学特征和精确定年,具有重要的地层对比意义。目前,全球各地已经开展了许多火山灰年代学与地层学的研究。在中国,尤其是东北地区,虽然有着丰富的火山资源,但是火山灰年代学与地层学的研究工作依然比较匮乏,本文简要回顾了一下中国东北、欧洲、新西兰、日本、俄罗斯等地区的火山灰研究工作,旨在为以后的研究提供一定的参考资料。  相似文献   

11.
松属(Pinus L.)约113种,是松科现代属中最原始的类群。松属植物种类丰富且研究领域广泛,对其已经积累的资料数据进行系统梳理总结十分必要。本文通过总结国内外松属大化石资料,结合分子系统发育、地质背景和地理隔离事件讨论了其地史分布及植物地理学意义;该属化石在早白垩世至全新世地层中均有记录。化石证据表明松属很可能在早白垩世(之前)起源于西欧地区,从这一起源地通过北大西洋陆桥扩散到北美洲东部,而东亚的类群可能是从北美洲西部经过白令陆桥散布的。在晚白垩世分化出双维管束松亚属Subgenus Pinus L.及单维管束松亚属Subgenus Strobus (D. Don) Lemmon,前者更接近祖先类群。古新世由于全球显著增温以及白垩纪末期大灭绝等地质事件的影响使松属数量急剧减少,在晚始新世至中新世时期随着气温转凉转冷再次分化扩散,中新世达到其发展高峰且分布面貌与现代类群近似。松属多样性时空历史可能和新生代气候变迁及晚新生代构造运动塑造的山地隆升等环境变化紧密相关。  相似文献   

12.
Platydemus manokwari is a broadly distributed invasive terrestrial flatworm that preys heavily on land snails and has been credited with the demise of numerous threatened island faunas. We examined whether P. manokwari tracks the mucus trails of land snail prey, investigated its ability to determine trail direction, and evaluated prey preference among various land snail species. A plastic treatment plate with the mucus trail of a single species and a control plate without the trail were placed side by side at the exit of cages housing P. manokwari. All trials were then videotaped overnight. The flatworms moved along plates with mucus trails, but did not respond to plates without trails, blank control (distilled water), or with conspecific flatworm trails. When presented at the midpoint of a snail mucus trail, the flatworms followed the trail in a random direction. The flatworms showed a preference when choosing between two plates, each with a mucus trail of different land snail species. Our results suggest that P. manokwari follows snail mucus trails based on chemical cues to increase the chance of encountering prey; however, trail-tracking behavior showed no directionality.  相似文献   

13.
Renewable generating technologies offer an effective means for climate change mitigation. Policy makers, however, are wary because of the widespread perception that these technologies cost more than conventional alternatives so that increasing their deployment will raise overall electricity generating costs. Energy planning represents an investment-decision problem. Investors commonly evaluate such problems using portfolio theory to manage risk and maximize portfolio performance under a variety of unpredictable economic outcomes. Energy planners need to similarly abandon their reliance on traditional, “least-cost” stand-alone kWh generating cost measures and instead evaluate conventional and renewable energy sources on the basis of their portfolio cost – their cost contribution relative to their risk contribution to a mix of generating assets. Energy security generally focuses on the threat of abrupt supply disruptions. This paper suggests a more profound aspect: mitigating fossil price volatility. An extensive body of research indicates that fossil volatility significantly disrupts the economies of consuming nations, potentially exacting hundreds of billions of dollars from the US and EU economies alone. Energy security is reduced when countries hold inefficient portfolios that are needlessly exposed to fossil price risks. This paper describes essential portfolio-theory ideas and uses three case studies to illustrate how electricity-generating mixes can benefit from additional shares of wind, geothermal and other renewables. Compared to existing, fossil-dominated mixes, efficient portfolios reduce generating cost while including greater renewables shares in the mix thereby enhancing energy security. Though counter-intuitive, the idea that adding more costly renewables can actually reduce portfolio-generating cost is consistent with basic finance theory. An important implication is that in dynamic and uncertain environments, the relative value of generating technologies must be determined not by evaluating alternative resources, but by evaluating alternative resource portfolios.  相似文献   

14.
Snail control is one of the most important tools in the campaign to reduce the incidence of fascioliasis. In order to attain this objective, the method of bait formulation in order to contain an attractant and a molluscicide is an expedient approach to lure the target snail population to the molluscicide. This study identifies certain carbohydrates, namely sucrose, maltose, glucose, fructose and starch, for preparing such baits. These were tested on Lymnaea acuminata, an intermediate host of the digenean trematodes Fasciola hepatica and Fasciola gigantica. The behavioural responses of snails to these carbohydrates were examined. Significant variations in behavioural responses were observed in the snail even when the five carbohydrates were used in low concentrations in snail-attractant pellets. Starch emerged as the strongest attractant for Lymnaea acuminata, followed by maltose.  相似文献   

15.
Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.Electronic supplementary material  Supplementary material is available for this article at and is accessible for authorized users.  相似文献   

16.
张子晗  聂禄敏  陆恒 《地球环境学报》2024,15(2):224-234, 305
在气候变暖的背景下,川西高原积雪出现剧烈变化,对地区水循环过程、生态系统以及社会经济带来严重影响。基于MODIS积雪遥感数据以及环境因子数据,通过构建稳定度指标及最大熵模型探讨川西高原不同稳定性积雪的空间分布格局及其驱动因子,并对不同稳定性积雪的适宜分布区进行分析,结果表明:(1)川西高原大多数地区的积雪属于高度不稳定性积雪,其他稳定性积雪在川西高原分布面积较小;(2)川西高原积雪在海拔越高的地方稳定性越好;(3)不同稳定性积雪分布格局的影响因素存在差异,海拔和降水是影响稳定性积雪分布格局的主要因素。  相似文献   

17.
中亚兴都库什、喀喇昆仑及天山山脉(HKT)是气候变化敏感区,其在全球变暖背景下的气候变化对区域生态和经济系统的稳定性及可持续发展有重要意义。目前对中亚高海拔地区的研究多集中于局部区域,有关HKT地区气候变化的综合对比分析较为缺乏。本文对HKT地区现代气候变化的相关研究成果进行简单梳理和回顾,重点总结了HKT地区气候变化特征、影响机制及其与全球变暖的联系。结果表明:(1)近60 a,HKT地区不同区域气候的时空特征存在差异,从时间上看,天山的年均温及年降水量均呈上升趋势,而兴都库什-喀喇昆仑山的年均温呈不显著增加趋势,其年降水量变化趋势不稳定;从空间上看,HKT地区山脉南坡气温高于北坡,但北坡降水量高于南坡,且天山南北坡年降水均呈上升趋势。(2)HKT地区的气候变化除了受西风环流、南亚印度季风及局地条件等影响外,还受到北大西洋涛动和厄尔尼诺-南方涛动等大尺度气候模态的调制,如兴都库什-喀喇昆仑山脉在NAO正(负)位相和ENSO暖(冷)位相降水趋于增加(减少)。  相似文献   

18.
Most living mammal orders, including our own, started their career during the first 10 million years of the Cenozoic, the Age of Mammals. The fossil record documents that early Paleogene adaptive radiations of various clades included tiny species of the size of living shrews. Remains of particularly diminutive limb bones are described from the late Paleocene site of Walbeck, Sachsen-Anhalt. Discovered in 1939, it has remained the only known Paleocene mammal-bearing locality from Germany. The remains are referred to the family Adapisoriculidae, which is considered on the basis of the present postcranial evidence to represent plesiadapiform primates rather than alleged lipotyphlan insectivores as previously proposed. The Walbeck fossils compete with the Early Eocene species Toliapina vinealis from Europe and Picromomys petersonorum from North America for the status of the smallest known primate, fossil and living. Their estimated body weights are as small as 10 g. The limb bones show features related to enhanced flexion at the elbow and hip joint, suggesting arboreal habits and environments such as terminal branches. The diminutive size and tooth morphology suggest feeding on small insects and other invertebrates. Postcranials are important to assess early radiations, such tiny specimens as the present ones are extremely scarce in the fossil record, however.  相似文献   

19.
The steppe pika (Ochotona pusilla), a representative of the lagomorph family Ochotonidae, is restricted today to Kazakhstan and Russia. This subspecies-rich form belongs to a morphologically distinct, monospecific group of relatively small pikas, inhabiting steppe-like habitat. In the fossil record, it serves as a bioindicator of dry, grassland environment. The steppe pika was abundant and widespread in Europe during the Last Glaciation, and its unquestionable presence has been reported there since the middle Pleistocene. A new discovery of O. pusilla, from the Kielniki 3B locality (Poland), dated to the latest Pliocene, moves back the species appearance in Europe about one million years, almost coeval with its first record from the late Pliocene of Kazakhstan. Presence of such a typical steppe inhabitant as O. pusilla indicates significant climate change towards more arid, continental conditions, which started influencing Europe at 2.6 Ma. We present the first reliable record of the earliest O. pusilla entry deep into Europe in the latest Pliocene.  相似文献   

20.
It has been shown that preparedness to respond effectively to imminent abrupt climate change, getting CO2 levels down towards pre-industrial in a few decades, involves the promotion of specific technology types that can be the basis for a negative emissions energy system (Read and Lermit 2003/5). In particular, Bio-Energy technologies linked to technologies for CO2 Capture and Storage (BECS) or to other carbon disposal technologies, if done on a sufficiently large scale, can achieve this result given a context of policy urgency that also yields advances in energy efficiency and the take up of ambient energy technologies (wind, solar, etc.) in line with low emissions energy scenarios (e.g. the fossil free energy scenario developed by the Tellus Institute for Greenpeace International (Lazarus et al. 1993). It has also been shown (Read 1999, 2000, 2000a) that, if account is taken of inter-temporal beneficial learning externalities, it is efficient to reward innovation in policy-desirable technology types (e.g. through project-based schemes that embody such technology types) by a greater amount than the penalty on emissions. Such dynamic efficiency can be achieved through establishing a secondary market for project based credits exchanged for a number of emissions permits M(t) (M > 1 for t < H, the time horizon for policy) and with the variation of M(t) over time corresponding to the dynamically efficient path. This results in the incentive for project based emissions reductions being M(t) times greater than the penalty on emissions. By making use of the initial allocation of permits in each time period, an aspect of emissions permit trading that has no efficiency function under either auctioning or ‘grand-fathering’, this arrangement enables project based credits to be administered flexibly whilst ensuring the integrity of the emissions cap. The purpose of this article is to link these two bodies of work to show how a dynamically efficient response to the threat of abrupt climate change can be implemented in a way that is compatible with the response to gradual climate change that has been negotiated in the Kyoto Protocol. The design of such a dynamically efficient mechanism is considered, having as its objective the promotion of the two technology types mentioned above. A particular institutional model for implementing such a mechanism is described that mimics managerial behaviour in the adoption of new technology, avoids the additionality requirement that burdens the operation of the CDM in its current form, and aims to achieve ‘industry friendliness’ as a necessary condition of effective implementation.  相似文献   

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