The Migif–Hafafit gneissic complex of the Egyptian Eastern Desert: fold interference patterns involving multiply deformed sheath folds

The Wadi Hafafit Complex (WHC) is an arcuate belt of orthogneisses, migmatites and other high-grade metamorphic rocks, which marks the boundary between the Central Eastern and the South Eastern Deserts of Egypt. In the WHC, gneissic meta-gabbro outlines macroscopic fold interference patterns characterized by elliptical to irregular culminations cored by gneissic meta-tonalite to meta-trondhjemite. The five main culminations of the WHC have previously been labeled A (most northerly), B, C, D and E (most southerly). A detailed structural investigation of B, C, D and E reveals that these structures are a result of the interference of four macroscopic fold phases, the first three of which may represent a single deformation event. The first folding involved sheath-like fold nappes, which were transported to the N or NW, assisted by translation on gently dipping mylonite zones. The regional gneissosity and mineral extension lineations formed during this folding event. The fold nappes were deformed by mainly open upright small macroscopic and mesocopic folds with approximately NE-trending hinges. As a probable continuation of the latter folding, the sheaths were buckled into large macroscopic folds and monoclines with the same NE-trends. The fourth macroscopic folding resulted from shortening along the NE–SW direction, producing mainly NW–SE-trending upright gently plunging folds. Gravitative uplift is disputed as a component of the deformation history of the WHC. The peculiarities of the fold interference pattern result from the interesting behaviour of sheath folds during their refolding.     

Small-Mammal Data on Early and Middle Holocene Climates and Biotic Communities in the Bonneville Basin, USA

Archaeological investigations in Camels Back Cave, western Utah, recovered a series of small-mammal bone assemblages from stratified deposits dating between ca. 12,000 and 500 ¹⁴C yr B.P. The cave's early Holocene fauna includes a number of species adapted to montane or mesic habitats containing grasses and/or sagebrush (e.g., Lepus townsendii, Marmota flaviventris, Reithrodontomys megalotis, and Brachylagus idahoensis) which suggest that the region was relatively cool and moist until after 8800 ¹⁴C yr B.P. Between ca. 8600 and 8100 ¹⁴C yr B.P. these mammals became locally extinct, taxonomic diversity declined, and there was an increase in species well-adapted to xeric, low-elevation habitats, including ground squirrels, Lepus californicus and Neotoma lepida. The early small-mammal record from Camels Back Cave is similar to the 11,300–6000 ¹⁴C yr B.P. mammalian sequence from Homestead Cave, northwestern Utah, and provides corroborative data on Bonneville Basin paleoenvironments and mammalian responses to middle Holocene desertification.     

Where the buffalo roam: Boundaries and the politics of scale in the yellowstone region

For more than twenty years, the state of Montana has pursued a controversial policy of lethal control to manage winter migrations of bison from Yellowstone National Park. In the late 1990s, as the state and a number of federal agencies attempted to cooperatively outline a more palatable scenario for bison management, local environmental groups became active participants in the debate. This paper examines the strategies pursued by these organizations in the course of their attempt to construct a new, ecosystem-level territorial space and jurisdictional scale for bison, and places their struggle within the context of existing work in geography on the politics of scale. Ultimately, the failure of their efforts illustrates some of the important constraints faced by social groups that attempt to create new territorial regimes and new scales of resistance in the interstices of existing political structures.     

2001年三次6级左右地震前西昌地磁的虚假异常研究

2001年，在西昌地磁台300km范围内连续发生了三次6级左右地震；即2月23日在西昌北200km的四川雅江县境内发生的6．0级地震；5月24日在西昌西南140km的盐源县内境内发生的MS5．8地震，10月27日在西昌西南260km的云南永胜发生的MS6．0地震。震前，西昌地磁台各相对观测记录分量和绝对观测量都发生了明显的异常变化。研究结果表明，由于邻近基建施工，使观测环境发生改变，引起大幅度虚假异常，这些异常 尽管与三次地震对应较好，但不是先兆异常。     

坝上高原安固里淖粒度年纹层与环境变化

在安固里淖湖心区获取一未扰动沉积物样柱，分析发现了由冬季风搬运物与湖心沉积共同形成的粒度年纹层，建立了纹层年表，恢复了安固里淖湖区8507aB.P，以来的环境变化过程。8507-5429aB.P。冬季风活动较弱，后期的所波动；5429-3244aB.P.冬季风活动较强，3244-2494aB.P。冬季风活动减弱；2494-1165aB.P。冬季风活动略有增强；1165aB.P以来，冬季风活动减弱。安固里小淖粒度年纹层反映的冬季风变化情况与我国北方地区同期的环境变化和海平面变化有很好的对应关系。     

战略环境评价若干问题研究

分析了传统环境影响评价制度的不足，回顾了战略环境评价的研究与实践进展，阐述了战略环境评价与环境可持续发展的关系，并对以实现环境可持续发展为目标的战略环境评价体系所存在的问题进行了分析。     

山岳型旅游区人文建筑环境后效与调控模型

许多山岳型旅游区内或其流域上游，都建有人文建筑，而且在急剧增多，导致自然环境日趋恶化，其中乱建疗养院和旅馆的影响最为严重。通过地监测并全面分析张家界环境演变趋势，发现住宿施对环境的影响，比其他游乐设施更为明显。张家界国家森林公园生态环境的脆弱因子是金鞭溪水质。金鞭溪水质恶化主要表现为蓝藻，绿藻迅速繁殖，感官质量下降。主要原因是磷污染较重，总磷年均值100%超标。本文提出了基于环境脆弱因子的动态阈值调控模型，通过计算得出：在不超出张家界景区最为脆弱的环境因子-金鞭溪水质标准：总磷≤0.02前提下，金鞭溪上游接待区住宿设施生态阈值的动态系列：春季临界床位数为1186，夏季为3057，冬季为545，秋季为333。目前的建筑规模已超过了金鞭溪上游接待区住宿设施生态阈值。     

湿地旅游可持续发展研究

湿地以其独具特色的自然和文化景观为湿地旅游提供了有利条件。本文在可持续发展思想的基础上提出了湿地旅游这一概念，分析了湿地旅游发展与湿地环境保护之间的关系；针对湿地生物多样性、景观多样性、文化多样性等特点对湿地的旅游价值作了进一步的探讨，提出了湿地旅游可持续发展的几点对策。     

资源环境与社会经济协调发展探析

文章首先回顾了资源环境与社会经济发展的理论，提出资源环境与社会经济协调发展内涵：一方面，要在资源环境承载力范围内发展社会经济，追求社会经济发展的最大化，另一方面，环境承载力是动态的，要依靠社会经济发展不断提高，这两个方面是相互作用、相互制约的。在此基础上，详细论述了资源环境与社会经济协调发展的内容,并从社会经济发展、资源环境管理等角度探讨了资源环境与社会经济协调发展的政策调控，通过建立节约型国民经济体系、深化资源环境管理，实现区域一体化，以保证资源环境与社会经济协调发展的实现。