中国西北地区丹霞地貌景观特征、空间分布及保护利用初探

笔者等选取中国西北地区90处重点丹霞地貌（广义）地质遗迹为研究对象,对选取的遗迹进行景观特征分析,并采用Arc GIS进一步探讨其空间分布特征。我国西北地区丹霞地貌(广义）的整体空间分布,呈西北—东南方向“L形”分布,笔者等运用最邻近指数法和核密度分析法,得出其空间结构类型为集聚型,并形成5个高密度区。目前,研究区存在保护利用家底不清、顶层设计匮乏等问题,未来应通过建立丹霞地貌脆弱性评价和措施体系,推进世界丹霞地质遗迹品牌和IP建设等途径,探讨西北地区丹霞地貌（广义）保护利用的具体方式。     

中国东南部丹霞地貌区小尺度植被分异结构研究

陡崖坡广泛发育是丹霞地貌的基本形态特征。典型的丹霞地貌山块往往四面陡崖,山块之间也因此形成被陡崖围合的沟谷。特殊的地貌造就了许多特殊的小生境,产生了特殊的植被分异现象。本文梳理了山地自然分异和丹霞地貌生态与植被分异方面的研究文献,发现人们对于丹霞地貌区小尺度植被分异的关注不足。为此,针对丹霞地貌区小尺度植被分异这个最具有个性化的自然分异现象与本质进行了初步探讨,得到主要结论：丹霞地貌区小尺度的自然生态分异不符合一般意义上山地自然带分异规律,其根本原因在于地貌所引起的生境差异;丹霞地貌区的山顶效应实质上是“干岛”效应,其沟谷效应实质上是一种“热岛+湿岛”效应;孤立山顶的边缘形成生态结构“突变带”,使得山顶形成孤立的“环状生态圈层”;因地貌差异形成的小生境差异,决定了丹霞地貌区的植被分异图谱。这种小尺度植被分异研究能够丰富中国山地科学研究,并为丹霞地貌区植被生态环境保护提供一定的参考。     

Late Quaternary terrace formation from knickpoint propagation in the headwaters of the Yellow River,NE Tibetan Plateau

Upstream knickpoint propagation is an essential mechanism for channel erosion, carrying changes in base level, tectonics and climate across the landscape. Generally, the terraces on cross-sections at steady-state conditions have been widely reported. However, many landscapes in the field appear to be in a transient state. Here, we explore the mechanism of knickpoint initiation and fluvial evolution in a transient setting in the northeastern Tibetan Plateau. Analysis of channel profiles and terrace correlation indicates that the Yellow River is adjusted to match the increase in differentiated fault activity and climate change in a regional setting of continuous uplift. Consequently, a series of terraces were formed, and the number of terrace steps increased downstream, in the headwaters of the Yellow River. All terraces were dated using the optically stimulated luminescence method. The top terrace, distributed continuously in the whole basin with a gradient, was deposited during a cold period and abandoned at the climatic transition from cold to warm state, at approximately 14.6–9.5 ka. After that, one terrace formed at around 4.2 ka in the upper reach. In correlation with the continuous topographic gradient surface of this terrace, three terrace steps were formed in the down reach during the period from 9.5 ka to 4.2 ka. This phenomenon might indicate multiple phases of continuous headward migration of fluvial knickpoint waves and terrace formation during the downcutting. It was caused by fault activity and tectonic uplift of the gorge at the outlet of the basin, under influence of the gradual integration of the Yellow River from downstream. This phenomenon shows that the fluvial incision in a transient state along the high relief margin of the orogenic plateau can be caused by fault activity, in addition to widespread surface uplift, climatically driven lake spillover and the establishment of external drainage.     

南海海底地形可视化分析及其地质意义

海底地形是海洋地质学、海洋地球物理学、物理海洋学和海洋生物学等研究的基础资料,是影响海洋要素分布的重要因素之一。可视化是地形数据解译的关键,它为揭示海底地形与其他海洋要素之间所蕴含的关系和规律提供了独到的方法。基于可视化工具Vertical Mapper,在MapInfo Professional中对南海海底地形信息进行了渲染图与三维可视化实现,并对地形进行了剖面分析,进而将可视化的南海海底地形信息与表层沉积物类型、流场等其他海洋要素信息进行叠加分析,由此探讨了表层沉积物类型的分布与地形、海洋动力条件等的空间相关性,说明海底地形的可视化对于海洋地质现象的解释具有重要的意义。     

昌马断裂带活动构造地貌之研究

本文根据野外地质调查资料和人工探槽的剖折,并结合¹⁴C年龄数据,讨论了昌马活动断裂带晚更新世晚期以来形成的构造地貌的类型、特征及分期问题.     

云南东川地区层状地貌面的成因

在东川地区的山地及小江河谷的两侧山麓上部，分布着不同高度和不同规模的层状地貌面，对其成因仍有不同的认识。分歧主要表现在两个方面：一是高原隆升之前的初始地貌面是否是准平原型夷平面；二是山顶面之下的梯级层状地貌面的成因。本文从以下几个方面对上述问题进行讨论：(1)层状地貌面的地貌特征及其与侵蚀河谷体系的关系；(2)层状地貌面上堆积物的性质；(3)层状地貌面与断裂构造水平展布的关系；(4)相邻层状地貌面的空间过渡关系；(5)区域构造演化背景。作者认为在云贵高原抬升过程中，东川地区以挤压穹起隆升变形为主。不同海拔高度的层状地貌面具有多成因特性。山顶面及局部高原面是高原隆升之前古夷平面的残留。并遭到后期强烈的侵蚀改造。目前，尚缺乏足够证据证明高原隆升之前的古夷平面为准平原型夷平面。小江河谷两侧的梯级层状地貌面是侵蚀或剥蚀面，它们形成于高原隆升及初始地貌面解体之后，其梯级空间分布特征与区域性的阶段隆升有关。     

沪蓉高速公路西段喀斯特发育特征及其对工程的影响

简要介绍了沪蓉国道主干线湖北省高坪-吉心段的喀斯特地貌特征，分析其发育和形成原因，并对区域喀斯特发育史作了研究。通过不同地层岩石的溶蚀性、喀斯特发育程度及地下水的赋存情况，区域水文地质条件及地下水和地表水的补给、径流、排泄运动关系，研究此区域的集中排泄和分散排泄两大喀斯特水系统的发育规律及规模，在此基础上探讨了喀斯特对路线工程的影响作用。     

渤海莱州湾南岸平原黄土阜地貌及其古地理意义

在莱州湾南岸滨海平原上发现一种新地貌类型黄土阜。研究表明，它形成于晚更新世晚玉木冰期。在此寒冷时期，渤海曾水退为平原，由于极少植被覆盖，形成陆架荒漠。裸露的海底松散沉积物被强劲的北风向南吹扬搬运，于南岸平原有利地形位置上沉积下来，形成厚层砂质黄土，并顺风向形成了阜状黄土地貌。     

Block gliding and rheological deformation in the Southern Sydney basin

Block gliding caused by low frictional resistance or by the deformation of plastic substrates has been well documented from many parts of the world, but neither of these mechanisms explains the widespread gliding of sandstone blocks away from cliffs in the southern Sydney Basin of south‐eastern Australia. The movement of large blocks over declivities from near zero to a maximum of 5°, high frictional resistance and lack of high porewater pressures rule out a simple sliding mechanism and it is unlikely that slender towers of sandstone could have survived seismic vibration sufficient to overcome frictional resistance to gliding. Highly preferential dip control of the direction of gliding and of the development of benches over which the blocks move, together with mounds, similar to pressure ridges, on the benches, indicate that the block gliding is due to the rheological deformation of the underlying rock, even though it is a sandy siltstone lacking readily deformable beds. Estimated rates of deformation are only 11 m/Ma to 270 m/Ma, but are commensurate with the rates of erosional retreat of clifflines estimated from K‐Ar and ¹⁴C chronologies. This phenomenon may be a significant feature of many slowly eroding landscapes, and prompts revision of models of long‐term geomorphological evolution.     

华南沿海现代海平面变动和新构造运动

近３０年验潮资料的年变速率的估算结果表明，华南沿海平均以１￣１．２ｍｍ／ａ速率抬升。新构造运动使各个不同岸段相对的海平面变动有如下差异：珠江三角洲和雷琼地区东海岸的海平面抬升速率明显超过１ｍｍ／ａ，闽东、粤东沿海则小于１ｍｍ／ａ，甚至呈下降趋势，局部岸段（如台湾海峡西岸）因海洋水文影响其上升速率也较大。