摘要
本文详细描述了河南安棚碱矿的4种岩石类型、沉积构造组合、沉积韵律和自生矿物特征,讨论了矿体的产状、分布、矿床的矿物组成和化学成分,并分析了碱矿床的成因。安棚碱矿是固体碱矿层和高浓度碱卤水并存的重碳钠盐矿床,是我国一个新的碱矿类型。该碱矿床是富含Na^(1+)、HCO_3^(1-)的淡水,在干盐湖环境中,从盆地边缘向盆地中心,经过一系列演化,形成富钠的重碳酸盐型卤水,在高二氧化碳分压下快速沉积形成的。
The Anpeng alkali deposit is located in the southeast part of the Biyang depression of the Nanxiang basin in Henan Province. The deposit occurs in Member 2, the top of Member 1 and the bottom of Member 3 of the Hetaoyuan Formation (Eocene). Member 2 is the chief alkali-bearing horizon. The alkali-bearing rock series is composed of sandtone, oil shale, dolomite and rock nahcolite. The form a rhythm at the section. Observation of drill cores shows that sedimentary structures that represent shallow-water and exposed sedimentary environments are well developed. Zeolite was formed mainly in the dolomite at the top and bottom of the alkali bed. There are also a lot of natrolites. The Anpeng alkali deposit consists of solid alkali ore and highly concentrated brine, which is an important characteristic of the deposit. The main mineral of the solid alkali bed is nahcolite with subordinate wegschederite. Trona and halite have not been discovered yet. So it is a bicabonate deposit—a new type of alkali deposit.
The Palaeozoic metamorphic rocks and some Yanshanian granite bodies at the peripheries to the Biyang depression offered Na^(1+) and HCO_3^(1-) for the lake basin. The sedimentary structures and sedimentary rhythm and the distributions of sedimentary facies reflect the sedimentary characteristics of the playa.
By studing the Anpeng bicabonate deposit, the authors consider that so long as there is enough CO_2 source from the brine of the alkali lake and the P_(co_2) remains high enough, rapid deposition was able to give rise to bedded nahcolite.
出处
《地质论评》
CAS
CSCD
北大核心
1991年第1期42-50,共9页
Geological Review
