Field observation and results of experimental studies show that Gongchangling rich iron deposit is characterized by multigenesis as a result of repetition of differcnt geological processes. It probably resulted from t...Field observation and results of experimental studies show that Gongchangling rich iron deposit is characterized by multigenesis as a result of repetition of differcnt geological processes. It probably resulted from the infiltration of silica under the influence of aqueous solutions derived from migmatite-granite. Because the formation of rich iron deposit was accompanied by the formation of skarn minerals and the transformation of sedimont-metamorphie poor iron deposits, characteristics of both skarn deposits and strata-bound ore deposits ean therefore be recognized. Experimental data indicate that physico-chemical parameters of formation of rich iron deposit are P =2kbar, T = 500--600℃, pH= 8--10, and fo2 = 10^-25 bar.展开更多
基金supported by the National Basic Research Program of China(973 Program)(Grant No.2006CB701400)Ministry of Education(Grant No.NCET-04-0727)the National Natural Science Foundation of China(Grant No.40272074).
文摘高分辨率的环境磁性的大小在孟加拉的海湾在 CoreMD77-181 上被执行，包括磁性的危险性，非滞后的残余的磁化，所有样品的等温的残余的磁化，和磁性的危险性的温度依赖和代表性的样品的磁性的磁滞现象参数。结果建议那(1 ) 磁性的矿物质集合上面 9.82 m 沉积(相应于最后 160 ka ) 被伪单人赛领域磁铁矿统治，与在冰川的时期的更丰富的粗糙的谷物比在间冰期的时期；(2 ) 最高沉积的 6.50 m (相应于最后 70 ka ) 在磁性的矿物质的谷物尺寸显示出重要时间的变化，可能反映在印度夏天季风的变化和诺思大西洋(Heinrich 事件) 的快速的冷事件之间的电视连接；(3 ) 在 9.82 m 下面的沉积被顺磁的矿物质(可能包括的黄铁矿) 统治，建议减少的成岩作用。核心 MD77-181 的磁性的记录在阿拉伯的海比得上在孟加拉，和 ODP Hole722B 的海湾的核心 MD77-180 的那些。这研究建议在 160 kasignificantly 改变了的 ~ 的苍白的海洋学的事件北印度洋的氧化还原作用状态，从在到 oxic 的事件前的减少的环境或在事件以后的 suboxic 环境。
文摘Field observation and results of experimental studies show that Gongchangling rich iron deposit is characterized by multigenesis as a result of repetition of differcnt geological processes. It probably resulted from the infiltration of silica under the influence of aqueous solutions derived from migmatite-granite. Because the formation of rich iron deposit was accompanied by the formation of skarn minerals and the transformation of sedimont-metamorphie poor iron deposits, characteristics of both skarn deposits and strata-bound ore deposits ean therefore be recognized. Experimental data indicate that physico-chemical parameters of formation of rich iron deposit are P =2kbar, T = 500--600℃, pH= 8--10, and fo2 = 10^-25 bar.
