三重県志摩半島の黒瀬川帯では，蛇紋岩中にドレライトが岩塊として産する．このドレライトは，本地域黒瀬川帯を特徴付ける岩石（黒瀬川古期岩類）の一つとされてきたが，ドレライト自体はジュラ紀付加体中にも海洋地殻断片として産する例があることから，本ドレライトの起源を明らかにするため全岩化学分析を行った．その結果，島弧ソレアイトの特徴を示すことが判明した．他地域の黒瀬川帯岩石との比較からも，本ドレライトは，海洋地殻起源の付加体要素ではなく，スープラサブダクション域に起源を持つ黒瀬川古期岩類に対比できる．また，四国黒瀬川帯の三滝火成岩類の一要素に相当する可能性がある．

富士山東方の静岡県小山町の新東名高速道路の2018年度建設工事現場で，大規模な火山性の斜面崩壊堆積物を確認し，大御神岩屑なだれ堆積物と命名した．この堆積物は，大洞山東斜面に堆積していた富士火山起源のスコリア降下火砕物が表層崩壊を起こしたもので，その南東山麓に長さ4.5 km，最大幅1.5 km，体積9.3×10⁶ m³の規模で広がっている．堆積物直下に神津島天上山テフラの降下層準があること，直上土壌の¹⁴C 暦年代から，発生時期は平安時代のAD 838から10世紀前半に特定された．この期間中には東海・南海連動の巨大地震であるAD 887の仁和地震が起きており，この地震動によって斜面崩壊が発生した可能性が強い．

中央構造線の北側に沿って小規模に分布する泉南流紋岩類は，西南日本内帯における後期白亜紀火山岩類分布域の南端にあたり，後期白亜紀花崗岩類に貫入され，和泉層群に不整合に覆われる．今回，淡路島に分布する泉南流紋岩類中の流紋岩溶結凝灰岩1試料を対象に，同一ジルコン結晶を用いたLA-ICP-MSによるU-Pb及びフィッション・トラック（FT）年代測定を行った．その結果，²³⁸U-²⁰⁶Pb年代の加重平均として94.0±1.1Ma（2σ）が，FT年代として72.3±2.6Ma（1σ）がそれぞれ得られた．U-Pb年代は，泉南流紋岩類を貫く花崗岩類の放射年代値とも調和的で，泉南流紋岩類の噴出年代に制約を与える．FT年代は，U-Pb年代より有意に若く，これは花崗岩類の熱的影響による若返り年代の可能性がある．

Glaciological studies have been conducted on snow patches in Japan since 1910th, including the recent identification of active glaciers in the Hida Mountains. This identification was presented at an open symposium organized by the Data Center for Glacier Research of the Glaciological Society of Japan, which recognized that the snow patches have a considerable mass of ice that shows evidence of downward flow along a valley. International cryosphere-related organizations, however, have defined the glacier as a “stagnant or flowing ice mass”, and the international classification of glaciers as published by The International Commission of Snow and Ice (ICSI) requires the criterion of flow for only certain classes of glaciers, such as the valley glacier etc. The presence of ice flow is not considered necessary to define mountain glaciers and glacierets. On the basis of a pilot study in the Himalayan region as used by the ICSI, several snow patches with ice masses in Japan can be considered as a type of glacier. However, the classification is unclear in terms of criteria based on flow, size, and thickness of an ice mass, as well as in terms of distinctions between valley glaciers, mountain glaciers, glacierets, and snow patches, which should be re-examined and clarified to create a better definition and classification of snow and ice masses on Earth.

We report petrographic characteristics and whole-rock chemical compositions of the Stage 3 (after 16 ka) eruption products of Kusatsu-Shirane Volcano, central Japan. The Stage 3 eruption products analyzed in this study are from the Shirane Pyroclastic Cone Group (SPCG), the Ainomine Pyroclastic Cone, and the Yumi-ike Maar, which are all located in the northern summit area of Kusatsu-Shirane Volcano. All lavas and juvenile pyroclasts of the Stage 3 eruption products contain phenocrysts of plagioclase, orthopyroxene, clinopyroxene, and opaque minerals. In addition to these minerals, some rocks contain rare olivine, quartz, and biotite phenocrysts. The lavas that were erupted during the early activity of the SPCG (the Hebei-ike, Kagusa, and Shirane-higashi lavas) have wide variations in SiO₂ content from andesitic to dacitic and in some outcrops exhibit a heterogeneous mingled appearance. In contrast, the lavas and pyroclasts that were erupted during the later stage of the SPCG (Shirane Pyroclastic Deposits and the Mizugama Lava Dome), as well as the Ainomine and the Yumi-ike Pyroclastic Deposits, are homogeneous in appearance and have andesitic compositions. Irrespective of the relative eruption ages, the analyzed Stage 3 eruption products are all associated with the calc-alkaline and medium-K series.