北疆区域地质调查阶段性成果与新认识

在介绍北疆沿国境线1∶25万区调修测项目阶段性成果基础上,据1∶25万区域地质调查新获得的地质事实与进展,结合区域性路线地质考查资料,对新疆北部准噶尔盆地东部阿尔曼太(扎河坝)蛇绿构造混杂带和准西部玛依勒山蛇绿岩带成因和构造背景提出新认识,初步认为阿尔曼太(扎河坝)蛇绿构造混杂带是华力西—印支期由南向北高角度逆冲推覆断裂铲起了早古生代(额尔其斯-卡拉麦里断裂间)增生杂岩楔(蛇绿岩块)推覆构造带;玛依勒山蛇绿岩带是具准洋壳特征的超基性岩、玄武岩及火山碎屑岩、硅质岩组合地层体,弱变形面状的分布,不具板块构造界线属性,表明其可能为哈萨克板块东南部陆缘裂谷中产物.     

Coexistence or contradiction? GM crops versus alternative agricultures in Europe

Agricultural biotechnology (agbiotech) has intersected with a wider debate about ‘sustainable agriculture’, especially in Europe. Agbiotech was initially promoted as an alternative which would avoid or remedy past problems of intensive agriculture, but such claims were soon challenged. Agbiotech has extended the dominant agri-industrial paradigm, while critics have counterposed alternatives corresponding to an agrarian-based rural development paradigm. Amid controversy over environmental and health risks in the late 1990s, an extra issue emerged − the prospect that genetically modified (GM) material would become inadvertently mixed with non-GM crops. In response the European Commission developed a policy framework for ‘coexistence’ between GM, conventional and organic crops. This policy has aimed to ensure that farmers can freely choose among different production systems, which would develop side by side, yet specific proposals for coexistence rules favour some choices over others. Such rules have been contested according to different policy agendas, each promoting their model of future agriculture. Moreover, a Europe-wide network of regional authorities has promoted ‘GM-free zones’ as a territorial brand for green, localised, high-quality agri-food production, whose diverse qualities depend upon symbolic, immaterial characteristics. This alternative has been counterposed to the agri-industrial production of global commodities - symbolised by the European Union, especially its product authorisation procedure for the internal market. ‘Coexistence’ policy was intended to mediate policy conflicts over GM crops, yet it has become another arena for contending agricultural systems, which may not so readily co-exist in practice. Wherever an agrarian-based rural development paradigm gains local support, its alternative agricultures are in contradiction rather than coexistence with GM crops.