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Pursuit of the XXX of the relationships between the origins of carbonaceous chondrites, micrometeorites, and interplnaetary dust particles.

碳质球粒陨石、微陨石和行星际尘埃粒子起源之间关系的探索。

基本信息

批准号：
13440158
负责人：
NOGUCHI Takaaki
金额：
$ 9.66万
依托单位：
Ibaraki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

1.We found more than 5000 micrometeorites from the fine-grained samples collected by the Japanese Antarctic Research Expedition Teams. The majority of the micrometeorites are heavily heated. Only about 1% of them experienced the least heating. We investigated the least heated micrometeorites by synchrotron radiation X-ray diffraction and TEM. Most of them contain abundant saponite as phyllosilicate. Next abundant ones contain both saponite and serpentine as phyllosilicates. Serpentine-predominant ones are revealed to be minor and comprises about 10% of the least heated ones. The most abundant type of phyllosilicate-rich micrometeorites has mineralogy similar to that of Tagish Lake meteorite. Next type resembles CI chondrites. Their parental asteroids are thought to be D-type and C-type asteroids, respectively. In other words, these data suggest that there are many micrometeorites derived from these types of asteroids.2.We also found hypercarbonaceous anhydrous micrometeorites. These mi … More crometeorites are composed of major carbonaceous material with relatively small amounts of anhydrous minerals such as olivine, low-Ca pyroxene, iron-nickel metal, and iron sulfides (and oxidized and weathered minerals of the metal and sulfide). Two such micrometeorites were sent to Washington University, St.Louis to search the presolar silicate grains in the meteorites. Two presolar silicate grains were discovered from tt54B397. The abundance of the presolar silicates is much higher than that of primitive meteorites. This kind of micrometeorites has an intimate relationship with hypercarbonaceous anhydrous interplanetary dust particles. The high abundance of presolar silicates suggests that this type of micrometeorites were probably derived from comets, P-type asteroids, and Kuiper belt objects.3.We analyzed mineralogy of carbonaceous chondrite clasts in the H chondrite regolith breccias. Most of them contain saponite or saponite and serpentine as the major phyllosilicates. However, the abundance of CM-like clasts is about 30%, which is higher than that of CM-like micrometeorites. Less

1.我们从日本南极研究探险队收集的细粒度样本中发现了5000多颗微陨石。大多数微陨石都是高温的。只有大约1%的人经历了最少的加热。利用同步辐射x射线衍射和透射电镜对微陨石进行了研究。它们大多含有丰富的皂石，如层状硅酸盐。其次丰富的含有皂石和蛇纹石作为层状硅酸盐。以蛇纹石为主的岩石较少，约占最不热岩石的10%。富层状硅酸盐微陨石最丰富的类型与塔吉什湖陨石具有相似的矿物学特征。下一类型类似于CI球粒陨石。它们的母小行星被认为分别是d型和c型小行星。换句话说，这些数据表明，有许多微陨石来自这些类型的小行星。我们还发现了高碳无水微陨石。这些铁陨石主要由碳质物质和相对少量的无水矿物组成，如橄榄石、低钙辉石、铁镍金属和铁硫化物（以及金属和硫化物的氧化和风化矿物）。两颗这样的微陨石被送往圣路易斯华盛顿大学，以寻找陨石中的前太阳硅酸盐颗粒。在tt54B397中发现了两个前太阳硅酸盐颗粒。前太阳硅酸盐的丰度远高于原始陨石。这类微陨石与高碳无水星际尘埃颗粒有着密切的关系。前太阳硅酸盐的高丰度表明，这类微陨石可能来自彗星、p型小行星和柯伊伯带天体。对H球粒陨石风化角砾岩中的碳质球粒陨石碎屑进行了矿物学分析。它们大多以皂石或皂石和蛇纹石为主要层状硅酸盐。而类cm碎屑的丰度约为30%，高于类cm微陨石。少