权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Organic geochemistry and mineralogy of mudstones affected by contact metamorphism

接触变质作用影响的泥岩有机地球化学和矿物学

基本信息

批准号：
15540431
负责人：
UJIIE Yoshihiro
金额：
$ 2.24万
依托单位：
Hirosaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

The content of organic carbon (Co), the composition of visual kerogen, vitrinite reflectance (Ro), statistical Thermal Alteration Index (stTAI) and X-ray diffraction in two series of Miocene mudtones near the dykes at Owani-machi, Minami-Tsugaru, Aomori, were measured to investigate the thermal effect of contact metamorphism on organic maturation and minerals in sedimentary rocks. The organic maturation by contact metamorphism progressed with decreasing distance from the dykes with regard to the content, composition and maturity of organic matter in sedimentary rocks. In the samples within 1.5 m from the dyke at Sabaishi, the contents of Co and amorphous kerogen increase with decreasing distance from the dyke. This phenomenon may be explained by the idea that liquid constituent generated from the kerogen under high temperature and high pressure was recombined the residual kerogen to form the coke-like material. It is recognized in a diagram of Ro against stTAI that the pathway of organic maturation caused by contact metamorphism is different from that by diagenesis. This difference between these two pathways attributes to the large gap of heating time and temperature scales, and of sensitivity of Ro and stTAI to heating time and temperature. Without suffering effect of contact metamorphism, organic maturation indicates equivalent between two series, while silica mineral zoning indicates that the Sabaishi series has more highly progressed diagenesis than the Moriyama series. Kuroishi and Mitsumenai faults made the Sabaishi area 330 m deeper than the Moriyama area just after the movements of the faults, Pliocene epoch. It is concluded that organic maturation was fixed after the fault movements, and that silica mineral zoning has maintained from the time before the fault movements.

通过对青森南津轻、大谷町两个岩墙附近中新世泥质岩的有机碳（Co）含量、可见干酪根组成、镜质体反射率（Ro）、统计热蚀变指数（stTAI）和X射线衍射分析，探讨了接触变质作用对沉积岩有机质成熟度和矿物的热效应。从沉积岩有机质的含量、组成和成熟度来看，接触变质作用的有机质成熟作用随着距离岩墙的距离的减小而进行。在1.5米以内的样品从岩墙在Sabaishi，Co和无定形干酪根的含量增加，从岩墙的距离减小。这一现象可以用干酪根在高温高压下生成的液体组分与残余干酪根重新结合形成焦状物质的观点来解释。在Ro-stTAI图解中认识到，接触变质作用引起的有机质成熟途径不同于成岩作用引起的有机质成熟途径。这两种途径之间的差异归因于加热时间和温标的巨大差距，以及Ro和stTAI对加热时间和温度的敏感性。在不受接触变质作用影响的情况下，有机质成熟度表明两个系列之间相当，而二氧化硅矿物分带表明Sabaishi系列比Moriyama系列具有更高的成岩作用。黑石和三目内断层的运动使三白石地区比森山地区深330 m，就在断层运动之后，上新世。可以得出结论，有机质的成熟度是固定的断层运动后，硅矿物分带保持从断层运动前的时间。