喀斯特石林发育演化的地表水土过程作用机制

喀斯特环境中地表水土过程对表层喀斯特过程具有重要意义。在石林区域的地质环境变化条件下,石林形成是从剥蚀夷平期的厚层红土覆盖环境下的石芽溶蚀发育,至厚层覆土受侵蚀后出露深大石芽,再至现代石林的多重侵蚀改造的宏观演变过程。与地表水土过程有关的的风化壳覆盖溶蚀机制与揭露侵蚀机制是石林发育演变中的两个关键机制。     

生物喀斯特微形态研究

运用光学显微镜和扫描电镜对我国及南斯拉夫和英国多种样品进行了生物喀斯特现象的观察和分析.在生物喀斯特溶蚀侵蚀方面,对地表及地下(洞穴、土下)生物(藻类、地衣、真菌等)喀斯特溶蚀侵蚀机制及其微形态,以及海岸各种生物(藻类及软件动物等)喀斯特侵蚀微形态特别是钻孔作用,进行了系统的研究.在沉积方面,总结了各种喀斯特沉积与生物的关系,对各种生物(细菌、真菌、藻类、苔藓类等)的喀斯特沉积及其微形态进行了观察研究.对生物喀斯特微形态与非生物作用形成的喀斯特微形态进行了分析比较,并讨论了生物喀斯特微形态研究的方法及理论意义和实际应用价值.     

云南石林喀斯特小生境木本植物多样性特征

喀斯特生境与生物多样性的关系及对人为干扰的响应是喀斯特生态恢复的重要内容。以石林世界地质公园为例对此进行研究。从喀斯特溶痕与植物生长发育关系角度看,石林的小生境可分出节理溶沟、裂隙溶沟、楔状槽沟、深溶蚀坑、溶蚀石堆、浅溶蚀盘、溶蚀穿洞、溶蚀井或圆形溶槽和溶蚀廊道等9种。这些小生境的长度在31~340 cm,宽度在10~261 cm。在原生林、次生林、灌丛和灌丛草地等四个群落中调查了各个小生境的木本植物,共记录40科92种,个体数11420株,其中以溶蚀廊道的木本植物总数最多,溶蚀穿洞最少。物种和数量保持最稳定的小生境是溶蚀石堆和裂隙溶沟。各小生境群落间的物种相似性指数很低。裂隙溶沟、深溶蚀坑、楔状槽沟、溶蚀石堆等小生境在人为强烈干扰后,仍保留有部分乡土植物繁殖体,其他小生境缺乏,这些繁殖体对生态严重退化区的喀斯特植被恢复具有重要意义。喀斯特生境的尺度影响森林植被的自然恢复。保护喀斯特地质遗迹可以促进生物多样性恢复和保护,石林世界地质公园提供了例证。     

路南石林现代喀斯特溶蚀速率研究

通过对路南石林风景区不同地貌部位、土层下不同深度和不同的自然环境下放置石灰岩溶蚀样片一年的溶蚀结果分析,对石林发育现代溶蚀速率得出这样的认识：（１）在除去石灰岩岩石对石林发育的影响后,降水量是溶蚀的主要动力;（２）在一般情况下,土下的碳酸盐岩溶蚀量大于地表２￣３倍,但土下的沉蚀与土壤的持水特性和所处的地貌部位有关;（３）植被在石林发育过程中的作用并不如所预想的大;（４）路南大小石林从现代溶蚀速度看     

则岔石林地质公园喀斯特地貌类型及形成机制

则岔石林地质公园位于甘肃省碌曲县,该处地貌完整地保存了高寒喀斯特的特征,具有典型性与稀有性。为了揭示其自然科学价值,促进自然资源开发与景观保护,基于前人工作基础,通过野外地质调查,以碌曲县区域地学为背景,介绍了则岔石林地质公园的喀斯特地貌类型,即以高原石林为主,一线天为亮点,小型溶洞为辅。继而从地质构造、岩性、水文气候、生物因素四方面分析了园内喀斯特地貌的形成机制。对完善我国高海拔地区岩溶系列地质遗迹的科学研究具有一定意义。同时,高寒喀斯特的生态化对南方喀斯特沙漠化的治理具有良好的示范作用。     

广西环江锥状峰丛喀斯特景观演化机制

广西环江喀斯特世界自然遗产提名地是贵州荔波喀斯特世界自然遗产地的拓展地。环江喀斯特地貌发育演化受岩性、地质构造、断层、节理、裂隙和地下水文系统等因素影响。岩层由纯度较高的石灰岩和白云岩等可溶性碳酸盐岩构成,地壳运动使该地抬升,岩层受力发生褶皱并隆起断裂,断层节理发育;降雨、较高的温度以及地表-地下水对可溶性岩石进行侵蚀-溶蚀作用,使侵蚀基准面下降,河流下切,地表因长时间受剥蚀和溶蚀,地貌演化由幼年期经青年期进入壮年晚期。发育成峰丛谷地、洼地、峡谷及峰林洼地、谷地、盆地和多层洞穴等为主的形态多样的锥状喀斯特地貌景观。环江喀斯特自寒武纪以来经历了形成山间盆地和石炭系巨厚碳酸盐岩的沉积成岩阶段及喀斯特化作用,地貌发育演化经过3个主要阶段,即褶皱断块山地―盆地形成阶段、喀斯特峰丛―峰林发育阶段和喀斯特峡谷形成阶段。演化模式遵循峰丛洼地→峰丛谷地→峰丛峡谷→峰林洼地→峰林谷地地有序正向演替规律。揭示了热带-亚热带锥状喀斯特地貌发育主要阶段及演化过程。     

地衣喀斯特侵蚀作用的初步研究

地衣喀斯特侵蚀作用是生物喀斯特的一个重要研究内容。本文通过对多种气候环境下的地衣喀斯特侵蚀作用及其形态的野外观察及室内镜下（光学显微镜及扫描电镜）微形态观察分析,讨论了岩表及石内地衣侵蚀形态类型的性质及其与地衣的特殊生物组织的联系。文中还讨论了地衣侵蚀的化学机制、物理机制和生物机制。     

"三元剥蚀"与路南石林发育

石林是一种稀有的喀斯特地貌景观,其发育演化有其独特的过程。本文提出了石林发育的"三元剥蚀"机制,通过对土下溶蚀速率、表土剥蚀速率与(石)柱顶剥蚀速率三者不同组合的分析,讨论了石林发育的方向与趋势,并对当前路南石林发育的阶段和方向进行了具体研究。研究表明,作为石林增长拔高源动力的土下溶蚀强度的影响范围是有限的,其下限约在土下10m处,而真正能促使石林快速发育的深度是在土下2m以内。在现代自然条件下,路南石林顶部的剥蚀降低速度为10.4mm/ka,土下的溶蚀加深速度为26.17 mm/ka,石林的实际高度仍以15.77mm/ka的速度在拔高;表土剥蚀速度为650mm/ka,石林的可见高度现正以639.6mm/ka的速度增加,土壤正以623.83mm/ka的速度快速变薄,表明虽然目前石林的可见高度仍在增加,但其发育的最佳时期已经过去。     

南京梁代石刻微侵蚀的研究

从地貌学角度较系统地分析了梁代石灰岩石刻表面自然毁损的微侵蚀机制，本文指出，雨水沿缝合线渗流，经多种地衣及兰藻、绿藻等生物作用而大大加强了溶蚀作用，导致石刻的崩解，并讨论此种特殊微侵蚀形态的形成机制在地貌学理论研究中的意义。     

锥峰和塔峰溶丘地貌的表层喀斯特带径流溶蚀形成机制

塔峰、锥峰和常态山是西南喀斯特地区的三种主要丘陵形态.表层喀斯特带径流溶蚀动力学机制可以较好的解释喀斯特坡地发育.表层喀斯特带的顺坡径流量大的喀斯特地区,坡地溶蚀速率高,易于塔峰和锥峰地貌的形成,反之,易于常态山地貌的形成.降水、岩层组构等环境要素控制了表层喀斯特带的顺坡径流量.西南喀斯特地区的这三种溶丘的空间分布和这些环境要素的区域差异有关.滇东高原、贵州高原和广西丘陵平原的岩性和大地构造条件差异不大,气候是这三地溶丘地貌形态差异的主要原因:滇东高原为西南季风气候区,降水量较低,表层喀斯特带顺坡径流量小,溶丘地貌以常态山为主;其余两地为东亚季风气候区,降水量较高,表层喀斯特带顺坡径流量大,溶丘地貌以锥峰和塔峰为主,其中,广西丘陵平原的降水量大于贵州高原,前者溶丘地貌以塔峰为主,后者以锥峰为主.     

Weathering as an indicator of the age of quaternary glacial deposits in Tasmania

Comparison of the degree of post‐depositional erosion and weathering to which different landforms and sediments have been subject over time provides a valuable aid to age differentiation of Quaternary deposits. A variety of parameters, including erosional modification both of depositional and older erosional landforms, the weathering of surface clasts and the weathering of subsurface clasts and matrix, has proven useful to Quaternary workers. However, time is only one of a number of factors that control the amount of weathering and erosion that occurs at a site. Examples from the glacial deposits of Tasmania show that if results useful for dating are to be obtained, it is essential to minimise the influence of other factors which may obscure a time‐dependent sequence.     

Two treatments of the origin of ridge topography in the Kuraiskaya depression of Gornyi Altai

On the basis of the regularities of channel flow dynamics and the propagation of the emptying wave, it is shown that the value of the mean flow velocity above the field of giant ripples necessary for the ridge movement cannot be attained under given hydraulic and geomorphological conditions. Presented are the erosional dissection mechanisms for the surface of fluvioglacial deposits which contribute to the subparallel occurrence of ephemeral streams.     

Soil erodibility and processes of water erosion on hillslope

The importance of the inherent resistance of soil to erosional processes, or soil erodibility, is generally recognized in hillslope and fluvial geomorphology, but the full implications of the dynamic soil properties that affect erodibility are seldom considered. In Canada, a wide spectrum of soils and erosional processes has stimulated much research related to soil erodibility. This paper aims to place this work in an international framework of research on water erosion processes, and to identify critical emerging research questions. It focuses particularly on experimental research on rill and interrill erosion using simulated rainfall and recently developed techniques that provide data at appropriate temporal and spatial scales, essential for event-based soil erosion prediction. Results show that many components of erosional response, such as partitioning between rill and interrill or surface and subsurface processes, threshold hydraulic conditions for rill incision, rill network configuration and hillslope sediment delivery, are strongly affected by spatially variable and temporally dynamic soil properties. This agrees with other recent studies, but contrasts markedly with long-held concepts of soil credibility as an essentially constant property for any soil type. Properties that determine erodibility, such as soil aggregation and shear strength, are strongly affected by climatic factors such as rainfall distribution and frost action, and show systematic seasonal variation. They can also change significantly over much shorter time scales with subtle variations in soil water conditions, organic composition, microbiological activity, age-hardening and the structural effect of applied stresses. Property changes between and during rainstorms can dramatically affect the incidence and intensity of rill and interrill erosion and, therefore, both short and long-term hillslope erosional response. Similar property changes, linked to climatic conditions, may also significantly influence the stability and resilience of plant species and vegetation systems. Full understanding of such changes is essential if current event-based soil erosion models such as WEPP and EUROSEM are to attain their full potential predictive precision. The complexity of the interacting processes involved may, however, ultimately make stochastic modelling more effective than physically based modelling in predicting hillslope response to erodibility dynamics.     

广州红砂岩文物保护新方法

当前环境污染日益严重,不少珍稀石质文物因缺少保护而遭受严重风化。为保护风化石质文物,文章将纳米材料和传统石质文物保护剂相结合,提出一种新的保护方法：用纳米二氧化钛银与NS-系列文物水性保护剂按一定比例调和,涂抹于红砂岩文物表面;一段时间后在其表面喷洒NS-系列文物水性保护剂。为检验新方法之功效,分别用该方法和NS-系列文物水性保护剂处理采自于广州的红砂岩文物样品,用高效液相色谱仪测定其有机酸种类和质量分数,发现前者较后者的有机酸质量分数明显减少。又经实验检测,发现该方法处理后的样品能经受水流冲刷,能耐酸碱腐蚀。这表明新方法既能防水、耐酸碱,又能降解有机酸;可以有效延缓石质文物风化,较传统石质文物保护剂具有更好的保护效果。     

EFFECTS OF SNOW JAMS ON FLUVIAL ACTIVITIES IN THE HIGH ARCTIC

During break-up in the High Arctic, ice jams are insignificant, but large quantities of snow accumulated in the valleys strongly affect fluvial processes. Near Resolute, Cornwallis Island, many channels were first formed in valley snow drifts and their positions were unstable. Channels carved in the snow can easily accommodate changing discharge by a modification of their width, depth, and velocity. This causes considerable variation in the at-a-station hydraulic geometry relationships.

The availability of sediment is locally restricted by the snow lining along the channels, although some fluvial sediments deposited on the snow revealed that peak flows could entrain very large boulders. Several depositional features observed in the study area also indicated that fluvial activities can extend over a broad zone beyond the confines of the summer channels.

This study suggests that, by increasing discharge, snow jams enhance the erosional power of streams, but by interposing between streamflow and the valley floor, the snow can limit the supply of sediments. Whether the erosional or the protectional tendency dominates will depend upon the snow jam characteristics along various segments of the High Arctic streams.     

地表风蚀物理过程风洞实验的初步研究

本文介绍了研究地表风蚀物理过程中风洞实验的方法、内容及结果。实验表明:净风对土表的风蚀作用微弱,即使在遭到大风吹刮时,土表的结壳仍不易受到破坏。但在挟沙气流作用下,却能使土表结壳遭到破坏,风蚀发展异常迅速。自然形成的土表结壳、经风选被粗化的土表和长有草丛的地表均有抑制风蚀的保护作用。本实验在方法上虽属初步尝试,但能说明沙漠化物理过程的一般机制,并为防治按漠化的措施提供依据。     

湘桂黔滇藏一线覆盖型岩溶地貌特征与岩溶(双层)夷平面

根据岩溶风化壳的发育条件及研究覆盖型岩溶特征,提出岩溶（双层）夷平面概念,认为研究区覆盖型岩溶是一个统一的岩溶（双层）夷平面的组成部分。其现阶段的存在形式如石林、岩墙等为后期不同程序风化－刻蚀作用的结果;其地貌形态多为土下成因,并随剥蚀程度、裸露时间环境的差异而叠加各种后期气下改造特征。     

Sedimentary record of tectonic and climatic erosional perturbations in an experimental coupled catchment‐fan system

This article deals with the stratigraphic record of a climatic or tectonic perturbation of an experimental coupled catchment‐fan system. Following Bonnet & Crave's results (2003), which suggest that it is possible to differentiate between climatic or tectonic causes of surface uplift of an erosional topography from the record of sediment flux output, we design a new experimental device to test this proposition in the sedimentary signal. This device allows the study of a coupled erosion–sedimentation system at the laboratory scale for given and changing uplift and rainfall rates. On the basis of experimental results, we propose a methodology to study alluvial fan architecture from large‐scale geometries to stacking pattern and sequence analysis. In these experiments, the erosional perturbation resulting from climate or tectonic forcing induces a typical dynamic in terms of both sediment supply and the ratio between the sediment and water supply, which controls the transport capacity. The four possible forcings (rainfall rate and uplift rate increase or decrease, respectively) then result in unique dynamics of the combined parameters such as the fan slope, apex aggradation, mean sedimentation rate, grain size distribution, bed thickness and frequency and facies stacking. We first analyse large‐scale geometries (onlap, toplap, downlap or truncation) and then fine‐scale sedimentological features (fining, thinning, coarsening, thickening) in order to discriminate the nature of the forcing. This conceptual model could be adapted to real world alluvial fans in order to recognize and separate the driving mechanisms from each other.     

西南极乔治王岛菲尔德斯半岛冷圈的结构特征

根据坑探、物探、测温资料和含冰量、含盐度的分析,讨论了菲尔德斯半岛的冻土上限及其垂直梯度的变化,并论证了石环区碗状冻结面的存在,提出了本区地壳冷圈的五层结构,即活动层、冻结砂砾石层、受海水渗透作用过的冻结火山岩层、无海水渗透影响的冻结火山岩层和未冻结的古陆基底层;肯定了离岸海下冻土的存在;发现了含盐量高的冻土电阻率可低达80Ω.m,并对冰缘地貌发育有抑制作用。