环保新秀——橄榄石的自述

我——橄榄石,是人类朋友消除二氧化碳危害的最得力的好帮手,人类科学家称赞我是保护地球生存环境的新秀。我属岛状结构的硅酸盐矿物,化学式(Mg,Fe)2[SiO 4],斜方晶系,晶体呈厚板状—短柱状,集合体为粒状,橄榄绿至黄绿色,贝壳状断口,玻璃—油脂光泽,折射率1.654~1.690,硬度6.5~7.0,密度3.2~4.4 g/cm3。我具有许多独特的优良品质,所以,我能为人类的工农业生产和环境保护以及地质找矿做出贡献。主要表现为以下用途:首先,我可做高级铸件的高档型铸砂。用我自身制作的橄榄石砂因无游离二氧化硅而无硅尘危害,且受     

津巴布韦南十字矿区钨矿床地质特征及成因探讨

南十字矿区钨矿床的形成与新太古代的中酸性侵入岩、太古宙的绿岩带有密切关系;钨矿体主要受控于近EW向展布的脆—韧性构造带F_1,且具有多期性和多阶段性;钨矿赋存于片麻状花岗闪长岩与布拉瓦约(Bulawayo)群近EW向展布的层间滑脱带内,受F_1脆—韧性剪切构造带控制,与太古代花岗闪长岩界线为断层接触,矿体主要为含钨绢英岩化花岗闪长质碎裂岩型,其次为石英脉型;该矿床的形成主要表现为两个阶段(含3个期次),即主成矿阶段(Ⅰ期)和弱成矿阶段(Ⅱ期、Ⅲ期)。钨元素的主要物质来源于区内的花岗闪长岩岩体和太古代布拉瓦约群地层。围岩蚀变发育,硅化、绢云母化、绿泥石化、黄铁矿化等蚀变与钨矿化关心密切。     

Petrography and mineralogy of new lunar meteorite MIL090036

MIL090036 is a previously unknown meteorite （a feldspathic lunar breccia） that was discovered in Antarctica. The detailed petrography and mineralogy of this meteorite forms the subject of this paper. It has a typical clastic texture that consists of various types of rock debris （e.g. anorthosite, gabbroic anorthosite, gabbro, regolith breccia, troctolite, microporphyritic crystalline impact melt and compound clasts）, mineral crystal fragments （e.g. pyroxenes, plagioclase, olivine and ilmenite） and feldspathic glass clasts. The ifne-grained recrystallized minerals and mineral clasts are cemented together in a glassy groundmass. The anorthite content of plagioclase in the gabbro （An81-83） and anorthosite （An88-93） both have relatively low calcium content compared to those from other breccias （An90-98）. The pyroxene composition （Fs12-35 Wo3-44 En22-79） in the rock debris, crystal mineral clasts and anorthositic glass clasts are relatively iron-deifcient compared to those from gabbro debris with melt glass （Fs37-65 Wo10-29 En21-49） and groundmass （Fs18-69 Wo3-45 En14-50）. In contrast, the pyroxene grains in the gabbroic anorthosite display a narrow compositional range （Fs24-27 Wo7-14 En59-69）. Olivine grains in mineral fragments and the groundmass have a wider compositional range （Fo57-79） than those in the rock debris （Fo67-77）. The Fe/Mn ratio in olivine is in the range of 47 to 83 （average 76） and 76 to 112 （average 73） in pyroxenes, and hence classify within the lunar ifeld. The characteristics of texture, mineral assemblage and compositions suggest that MIL090036 possibly originated from a region beyond that of the Apollo and Luna samples. Further study of MIL090036 is therefore likely to lead to a better understanding of the geological processes on the Moon and the chemical composition of the lunar crust.