Study on paleogeothermal condition in tectonic development of kyushu based on degree of diagenetic to metamorphic alteration of solid organic matter in the sediments

根据沉积物中有机质的煤化程度，分析了九州地区不同地质序列不同变质阶段的成岩程度。镜质组反射率被指定为等级参数，并对其光学各向异性进行了研究，以达到较高的蚀变程度。反射率值与自生沸石相、变质矿物相以及石墨化煤质的X射线分析数据进行了对比。不同沉积单元不同地质序列中分散煤质的镜质组反射率测量数据揭示了九州地区不同的古地温模式。内带第三系盆地内多处古地温梯度较高。火成岩活动热效应在内带西北侧更为明显和频繁。在外带，特别是岛本地体，Morotuka群和Hyuga群存在前-同运动期的有机变质作用。日津南群巨型橄榄岩中观察到了运动后热效应，而宫崎群未观察到运动后热效应。前第三系组的地质结构复杂，需要进一步研究才能更准确地分析九州山区的热史，尽管沉积物中没有那么丰富的分散煤质，根据现有的资料，表明了不同的局部热效应模式。

The degree of diagenetic to successive various level of metamorphic stages of various geologial sequences in Kyushu are analyzed by the rank of coalification of organic matters in the sediments. Vitrinite reflectance is designated as the rank parameter, of which optical ansotropy is studied for the higher level of alteration. The reflectance values are correlated to the authigenic zeolite facies and metamorphic mineral facies, and also to X-ray analytical data of graphitized coaly matter.The measured data of vitrinite reflectance of dispersed coalified matter from various geological sequences ofvarious sedimentary units have revealed various paleogeothermal pattern in Kyushu. Higher paleogeothermal gradient is found many localities within the Tertiary basins in the inner zone. The thermal effect originated from igneous activitty is more evident and frequent at the northwestern side of the inner zone. In the outer zone, especially in Shimanto Terrain, pre- to syn-kinematic organic metamorphism is identified in Morotuka and Hyuga Groups. Post- kinematic thermal effect is observed in huge olistoliths of Nichinan Group though the effect did not reach to unconformably covered Miyazaki Group. The geological structure of pre-Tertiary Groups is so complicated that it will require further investigation to analyze the more accurate thermal history of Kyushu mountain region, though there are not so abundant dispersed coaly matters in the sediments that suggest various patterns of local thermal effect based on present data.