• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文OA文献 >Volatiles on Solar System Objects: Carbon Dioxide on Iapetus and Aqueous Alteration in CM Chondrites
【2h】

Volatiles on Solar System Objects: Carbon Dioxide on Iapetus and Aqueous Alteration in CM Chondrites

机译：太阳系物体上的挥发物：依加图斯上的二氧化碳和CM球粒陨石中的水蚀

页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Volatiles are critical in understanding the history of the solar system. We conducted two case studies intended to further this understanding. First, we analyzed the presence of CO2 on Iapetus. Second, we evaluated aqueous alteration in CM chondrites.We studied the distribution, stability and production of CO2 on Saturn's moon Iapetus. We determined that CO2 is concentrated exclusively on Iapetus' dark material with an effective thickness of 31 nm. The total CO2 on Iapetus' surface is 2.3x108 kg. However, CO2 should not be present because it has a limited residence time on the surface of Iapetus. Our thermal calculations and modeling show that CO2 in the form of frost will not remain on Iapetus' surface beyond a few hundred years. Thus, it must be complexed with dark material. However, photodissociation will destroy the observed inventory in ~1/2 an Earth year.The lack of thermal and radiolytic stability requires an active source. We conducted experiments showing UV radiation generates CO2 under Iapetus-like conditions. We created a simulated regolith by mixing crushed water ice with isotopically labeled carbon. We then irradiated it with UV light at low temperature and pressure, producing 1.1x1015 parts m-2 s-1. Extrapolating to Iapetus, photolysis could generate 8.4x107 kg y-1, which makes photolytic production a good candidate for the source of the CO2 detected on Iapetus.We also studied the aqueous alteration of metal-bearing assemblages in CM chondrites. We examined Murchison, Cold Bokkeveld, Nogoya, and Murray using microscopy, electron microprobe analysis and scanning electron microscopy. Alteration on CM meteorites occurred within at least three microchemical environments: S-rich water, Si-rich water and water without substantial reactive components. Kamacite alters into tochilinite, cronstedtite, or magnetite. Sulfur associated alteration can form accessory minerals: P-rich sulfides, eskolaite and schreibersite.Additionally, we determined that there were two alteration events for some CM chondrites. The first formed a hydrated matrix prior to accretion, indicated by unaltered kamacite surrounded by a hydrated matrix. The second occurred after parent body formation. This event is indicated by large regions with consistent alteration features, surrounded by other regions of less altered material.
机译：挥发物对于理解太阳系的历史至关重要。我们进行了两个案例研究，旨在加深这种理解。首先，我们分析了Iapetus上CO2的存在。其次，我们评估了CM球粒陨石中的水相变化。我们研究了土星卫星Iapetus上CO2的分布，稳定性和产生。我们确定CO2仅集中在有效厚度为31 nm的Iapetus暗物质上。 Iapetus表面的二氧化碳总量为2.3x108千克。但是，不应存在CO2，因为它在Iapetus表面的停留时间有限。我们的热计算和模型表明，霜冻形式的二氧化碳在数百年内不会残留在Iapetus的表面上。因此，必须将其与深色材料复合。然而，光解离会在地球的大约1/2年内破坏观测到的库存。缺乏热稳定性和辐射稳定性需要有源源。我们进行的实验表明，紫外线辐射在类似Iapetus的条件下会产生CO2。通过将碎冰与同位素标记的碳混合，我们创建了一个模拟的巨石。然后，我们在低温和低压下用紫外线对其进行照射，从而产生1.1x1015份m-2 s-1。推断到Iapetus，光解可产生8.4x107 kg y-1，这使得光解生产成为Iapetus上检测到的CO2来源的良好候选者。我们还研究了CM球粒陨石中含金属组合物的水相变化。我们使用显微镜，电子探针分析和扫描电子显微镜检查了Murchison，Cold Bokkeveld，Nogoya和Murray。至少在三个微化学环境中发生了CM陨石的变化：富含S的水，富含Si的水和没有大量​​反应性成分的水。钾铁矿会变成斜辉石，方铅矿或磁铁矿。与硫有关的蚀变可形成辅助矿物：富P硫化物，埃斯科莱石和schreibersite。此外，我们确定某些CM球粒陨石发生了两个蚀变事件。第一个在吸积前形成了水合基质，其特征是被水合基质包围的未改变的钾长石。第二次发生在母体形成之后。此事件由具有一致变化特征的大区域表示，周围是变化较小的材料的其他区域。

著录项

  • 作者

    Palmer Eric Edward;

  • 作者单位
  • 年度 2009
  • 总页数
  • 原文格式 PDF
  • 正文语种 EN
  • 中图分类

相似文献

  • 外文文献
  • 中文文献
  • 专利

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号