硼矿床含硼地层的二元结构模式

通过对与沉积作用有关的硼矿床结构的研究表明，含硼地层都具有二元结构，即下部是富含硼的凝灰岩、安山岩或酸性岩，是成矿的物质基础；其上是弱盐化－强盐化环境下形成的含硼矿层的蒸发岩沉积，蒸发岩环境是成矿的必要条件。二元结构的含硼地层的形成与裂谷构造、板块俯冲带和碰撞带的发生、发展、演化紧密相关。硼矿床含硼地层二元结构模式的提出，将硼矿床成矿机制进一步深化，具有理论意义和指导找矿的实际意义

BINARY ASSOCIATION OF BORATE BEARING SEQUENCES IN BORATE DEPOSITS

Generally speaking, any of borate deposits including volcanosedimentary, mordern saline lake sedimentary, marine sedimentary and sedimentometamorphic,are characteristic of binary association of stratigraphy, in another word, the upper half of stratigraphic colume made up of acid lava, tuff and andesite comparaed with the lower half, of evaporite productive of borate under weak or strong salinational conditions. Borate materials taken up with volcanic eruption laid a material base for mineralization while arid evaporation served as a must for borate deposition , both vital to the formation of ores. Binary association of borate bearing sequences has been recognized as two modes: monocyclic association and multicyclic association, both of volcanic rock plus boron rich evaporite. Three sets of volcanosedimentary cycles have been distinguished from the metamorphic borate deposits in East Liaoning of China. Through investigating these cycles volcanic rocks, ore forming major and minor elements and rare earth chemistry,their ore forming materials are confirmed to be the same source,leading to the borate layers, despite different stratigraphic levels, showing a genetic link with each other.The binarity of borate sequences is properly attributed to initiation and evolution of rift belts, plate subduction zones and collision zones. This finding is resulted from deepening the research on the genetic mechanism of borate deposits, of theoretical and practical constraints on borate geology and ore hunting.