月球反射光谱学及应用

Reflectance spectroscopy of the Moon and its application

随着我国探月工程稳步开展以及未来深空探测需求,反射光谱学研究在我国重新受到重视。文中简要介绍了月球反射光谱学原理及其研究方法,并以"嫦娥三号"着陆场所在的雨海地区为例展示反射光谱学的部分应用。与背面斜长岩高地相对单调的光谱特征不同,雨海周边高地展示了多样性的吸收特征,岩石类型以苏长岩质岩石为主,橄榄石、辉石、尖晶石等矿物都有分布。月球上最古老的和最年轻的玄武岩在雨海盆地也都有分布。古老的中、低钛玄武岩以易变辉石为主兼有少量低钙普通辉石,年轻的高钛玄武岩富含橄榄石。雨海乃至整个风暴洋地区玄武岩较之其他月海玄武岩贫Ca。雨海地区的元素、矿物组成以及玄武岩时代都具多样性,该区是研究月球热演化的重要地区。

Reflectance spectroscopy plays an important role in the exploration of the Moon and planets.The payloads using the reflectance spectroscopy technology have been onboard almost all the missions except for some very few missions with special objects.This paper firstly briefly introduces the principles of reflectance and its research domain.Then two examples describing the application of the reflectance spectroscopy are shown.The first one shows the elements,spectra,and separation of basaltic units using reflectance spectroscopy.The second example shows the mineral diversity of the Imbrium region derived from the Moon Mineralogy Mapper（M3）data.The calibration of the instruments,quantitation of minerals and the mechanism dominating and altering the absorption are the key fields deserving of study in the future.The highland exhibits a mafic character and is dominated by the noritic composition.Imbrium has both the oldest and the youngest basalts of the Moon,suggesting the geologic diversity of this area.Mafic mineralogy of the basalts is characterized by abundant olivine in the late-stage Eratosthenian basalts and pigeonite to sub-calcic augite in Imbrian units,suggesting Ca-depletion of the Procellarum KREEP Terrane（PKT）compared to nonPKT.