Tohru Danhara's research while affiliated with NGH Japan Co., Ltd. and other places

... However, the simple magmatic heat transfer model disagrees with the polyphase nature of low-P/high-T metamorphism that has been recently recognized. Based on thermal models, Miyazaki et al. (2023) demonstrate that short-lived magmatic intrusions (1.2 My each) could create the thermal structure of the mid-crustal section exposed in the Ryoke belt. However, the relatively long duration of high-T metamorphism (~10 My) in the Mikawa area in the absence of contemporaneous and presently exposed, km-scale granitoid bodies suggests an additional heat source. ...

... In fact, as shown in Figure 1, it is evident that tailing on 230 Th occurs in thorium-rich minerals, such as monazite. Apart from the effort to date zircon U-Pb and U-Th simultaneously, recent progress of zircon U-Th dating methodology using LA-ICP-MS is summarized in [9]. ...

... The recent geochronological analysis of Harisma et al. 6 in the Late Cretaceous-Paleogene Nemuro Belt implied that the sediment of the Paleo-Kuril Arc was not only supplied with sediments from rocks of its local igneous origin but also from the Precambrian continental crust, suggesting that the Paleo-Kuril Arc originated along the southern end of the Okhotsk Block as a continental arc system during the Late Cretaceous. In contrast, another geochronological study suggested that the Paleo-Kuril Arc could have developed as an immature oceanic island arc system in the Late Cretaceous 7 because it did not detect detrital zircon grains before 85 Ma in the basal successions of the Tokoro Belt, which is part of the Paleo-Kuril Arc system 7 . The geochemical analysis of the ...

... Their results indicate that the felsic dike and sills in the Amakusa area were formed in a regional north-south extensional field, which is roughly perpendicular to the southwest Japan arc. The orientation of Miocene dike swarms and mineral veins in various parts of southwest Japan was used to estimate both arc-perpendicular extension around the median tectonic line (MTL) and arc-parallel extension in the fore-and back-arc regions (e.g., Haji et al., 2022;Haji & Yamaji, 2021). They compiled the results of these paleo-stress estimations in the southwest Japan arc and demonstrated that arcperpendicular extension in the Amakusa area can be compared with those around the MTL, the region where the Setouchi Volcanic Rocks are distributed. ...

... The flat-ramp-flat geometry since ca. 9 Ma in the crystalline nappes in eastern Nepal is constrained by fission-track zircon age and forward thermokinematic modelling (Nakajima et al., 2022). Finally, synform and antiform structures were developed, with a doming of the Tamor Khola Window (Fig. 11e). ...

... Ninomiya et al. [4] and Verolino et al. [5] proposed two petrographic case studies of marine volcanism. More in detail, Ninomiya et al. [4] applied a high-resolution ion microprobe dating technique to the Tsushima Lapilli Tuff underwater deposit (Tsushima Island, Japan) in order to reduce the uncertainty about its age of emplacement. ...

... Over the last 20 years, there has been an increase in the understanding of petit-spot volcanic settings, providing valuable insights into the nature of the lithosphere-asthenosphere system, particularly in the NW Pacific region (Hirano et al., 2006;Hirano and Machida, 2022). As with other implications, subducted petit-spot volcanic fields with geological disturbances on the seafloor play a role in controlling the hypocentral regions of megathrust earthquakes (Fujiwara et al., 2007;Fujie et al., 2020;Akizawa et al., 2022). Additionally, the vestige of hydrothermal activity due to petit-spot magmatism has recently been reported (Azami et al., 2023). ...