中国成镍带与找矿方向探讨

Geological characteristics of the nickel metallogenic belts in China and the prospecting orientation

中国镍资源丰富,同时也是镍资源消费大国。矿床类型相对简单,主要为岩浆型,其次为海相沉积型和风化壳型3种。矿床形成时代从中—新元古代一直延续到新生代,主要集中在新元古代和晚古生代两个高峰期;空间分布较为集中,主要分布在西北、西南和东北地区,往往具有成群分布的特征。大陆边缘裂解、碰撞造山期后伸展以及地幔柱是形成中国镍矿床的3种重要构造背景。在全国Ⅲ级成矿区带的基础上,以镍矿床的空间分布特征为基础,以成矿规律和成矿条件为依据,在全国范围内划分30个成镍带;对东天山、甘—新北山、龙首山、吉中—延边、康滇、扬子南缘等6个成镍带的主要特征进行了简单叙述;从成镍带的角度,探讨了中国镍矿找矿方向,认为深部找矿尤其值得重视。

China has rich nickel resources and is also a country of much nickel resources consumption. The nickel deposits are composed of magrnatic type, marine sedimentary type and weathering crust type in China. The formation epochs were from the Neoproterozoic to Cenozoic, with the Neoproterozoic and late Paleozoic being two peaks. The spatial distribution of nickel deposits is relatively concentrated： they are mainly distributed in Northwest, Southwest and Northeast China, frequently exhibiting clustered distribution. The continental margin breakup belt, the post-collision orogenic belt and the mantle plume are three important tectonic settings of the nickel deposits in China. In this paper, the authors divided the nickel deposits in China into 30 Grade-Ⅲ nickel metallogenic belts on the basis of the Grade-Ⅲ metallogenic belts, described briefly the spatial distribution characteristics, metallogenic regularity, metallogenic conditions and ore-forming features of the nickel deposits, summarized the main geological characteristics of six nickel metallogenic belts, which include East Tianshan, Gansu-Xinjiang Beishan, Longshoushan, central Jilin-Yanbian, Kang-Dian and southern margin of the Yangtze, and discussed the prospecting orientation for the nickel resources. It is held that the depth of the intrasion should be regarded as the favorable exploration target for the Ni sulfide deposit.