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九州大学総合研究博物館が所蔵する玉泉館資料の古代瓦から，飛鳥～平安時代に相当する瓦資料32点を選び，内部断面の電子顕微鏡装置（EPMA）による岩相分析を行った．瓦は部分的に内部が熔解している熔結組織と，内部が焼き固まっている焼結組織を呈するものに分けられる．焼結組織をもつ瓦断面からは，残存鉱物として，花崗岩由来の石英，斜長石，曹長石，正長石，黒雲母，白雲母，火山岩由来の火山ガラス，斜長石，黒雲母が観察された．材料物質はおおむねこれらの混合物であり，材料供給地の特定は難しい．含まれる火山ガラスは，その化学組成から姶良カルデラ起源の姶良Tn（AT）火山灰，鬼界カルデラ起源のアカホヤ（K-Ah）火山灰と同定された．瓦内部に残存する鉱物と火山ガラスの組み合わせによって，瓦の焼成温度を推定した．焼結組織を呈する瓦は雲母の残る低温焼成（650～850℃）と，雲母はないが火山ガラスを包有する中間焼成（850～1150℃）のものに分けられる．一方，熔結組織は高温焼成（1150～1400℃）によって作られたものであった．観察した高温焼成の瓦は比較的少数で，瓦生産の黎明期には，高温焼成技術が確立されていなかった可能性を示唆している．, A series of lithological analysis for ancient roof tiles has been carried out using the electron microprobe technique. Thirty-two roof tile samples were selected from the Gyoku-sen-kan collection in the Kyushu University Museum, and are typologically-dated from the Asuka to Heian Periods, corresponding to the 7th to the 12th centuries AD. Based on electron microscopic observation, the textures of roof tiles’ interiors are divided in two types, such as sintered and welded textures that correspond to lower and higher firing temperatures, respectively. From the sections of sintered textured samples, quartz, K-feldspar, albite, plagioclase, biotite and muscovite of granitic origin, and glass shards, plagioclase and biotite of volcanic origin were identified. Mineral and glass assemblages suggest source materials were mixtures and it is difficult to identify distinct source areas. The contained volcanic glasses are derived from Aira caldera (AT) and Kikai caldera (K-Ah), which are meaning the firing temperature was not reached about magma temperature. The results indicate that there are three different firing temperatures, namely: lower (650-850℃) with mica; medium (850-1150℃) with volcanic glass; and higher (1150-1400℃) without volcanic glass and welded texture. It is suggested that high-temperature firing technique of kiln was not established yet in the early period of roof tile manufacturing in Kyushu area.

北陸地方東部(金沢平野～富山平野間)に位置する活断層の平均変位速度を明らかにするために，本地域に広く分布する河成段丘群の編年を行った．本地域は，段丘構成層中に編年の指標となる火山灰層を純層で確認できることは稀であるために，本研究では段丘を覆う被覆土壌層の採取を行い，これに微量に含まれる火山起源の鉱物を用いて段丘形成時期の推定を行った．また，本地域は一般に圃場整備や都市化の影響を受け自然露頭に恵まれないため，砺波平野を除く各地域では被覆土壌層の採取を主にボーリング掘削によって行った．富山平野～金沢平野間に分布する河成段丘面は，被覆土壌層や段丘構成層に挟在する火山灰層の層位，段丘面の分布形態，開析程度，傾斜，現河床からの比高，礫層の風化程度等よりⅠ面～Ⅻ面の12面に区分される．これらの段丘面のうち，Ⅸ面構成層上位にはAT(26-29ka)が，Ⅶ面構成層上位にはDKP(55ka)が，Ⅳ面を覆う被覆土壌層下位にはK-Tz(95ka)がそれぞれ挟在する．本研究によって，北陸地方のような火山灰稀産地域においても，広域的な河成段丘面の編年・対比は十分に可能であることが確認された．, Fluvial terraces are widely distributed in the eastern part of Hokuriku region, composed of the Toyama, Tonami, and Kanazawa Plain, northern part of Central Japan. In this area, the age of terraces has not been reported, as volcanic ashes are rarely visible within terrace deposits and overlying loamy soil, and outcrops are quite few in this area. In this study, we carried out drilling survey on these terraces to obtain overlying loamy soil samples and extracted some well-known wide-spread volcanic ashgrains from these samples after ultrasonic washing. Late Quaternary fluvial terraces in the eastern part of Hokuriku region are divided into 12 levels: terrace 1 to 12 in descending order. Terrace 4 is overlain by the Kikai-Tozurahara tephra (95ka), Terrace 6 is overlain by the Daisen-Kurayoshi tephra (55 ka) and Terrace 8 is overlain by the Aira-Tanzawa tephra (26-29 ka), respectively. From the tephrochronology and the sedimentary facies of terrace deposits, we estimate that each terrace was formed at MIS (Marine Oxygen Isotope Stage) 6 (terrace 1), MIS 5e (terrace 2), MIS 5d (terrace 3), MIS 5c (terrace 4), MIS 5b or 5a (terrace 5), MIS 4 or 4-3 boundary (terrace 6), MIS 3 (terraces 7, and 8), MIS 3 or 3-2 boundary (terrace 9), MIS 2 (terrace 10), and Holocene period (terraces 11, and 12), respectively. This study shows that the combination of the drilling of loamy soil and the precise microtephra analysis of fluvial terraces in rarely volcanic ashes and outcrops area can estimate of the formative age of these terraces., 論説