第 四 紀 研 究 (The Quaternary Research) 30 (2) p. 203-211 July 1991

Glacial and Periglacial Paleoenvironments in the Japanese Islands1)

Yugo ONO2)

The paper reviews three main topics of recent studies of Quaternary glacial and periglacial environments in Japan: chronology of glaciations, showline elevation, and permafrost distribution in the Last Glacial age. Two glaciations have been recognized in the Japanese high mountains during the Last Glacial age. The younger one corresponds to the isotope stage 2, and the older one to the stage 4. The alpine glacier attained its maximum extension in stage 4, because of more favorable snowfall conditions in this stage. The oldest glaciations which have been morphologically defined correspond to the isotope stage 5d or 6. The distribution of snowline elevation during stage 4 in eastern Asia shows (1) an abrupt increase of snowline elevation at the eastern margin of Qinghai-Xizang Plateau; (2) no possibility of Quaternary glaciation in the Mt. Lushan area in Southeast China; (3) existence of snowline trough which streches from Formosa towards the mountains of the Japan Sea side of Japan, and (4) the high snowline elevation in Central and Northern Hokkaido, suggesting the winter dryness. The research of present alpine permafrost environment on Mts. Daisetsuzan, central Hokkaido, and the fossil periglacial phenomena in the lowland of Hokkaido have revealed that the island was mostly in the discontinuous permafrost zone in the Last Glacial age.

studies. Many authors have attempted year I. Introduction round measurements of the rate of solifluction, Studies of Quaternary glacial and periglacial frost creep and alpine debris flow, together with environments have shown considerable progress air and soil temperatures on the summit areas of during the decade since ONO (1980) reviewed the the Japan Alps and Daisetsuzan Mountains in research before 1980. KOAZE(1984) briefly Hokkaido, as ONO and FUKUDA (1987) and IWATA summarized the history and major results of (1989) have reviewed in detail. studies of Quaternary glaciations in Japan. In The aim of this paper is, therefore, to sum- the explanatory text for the "Quaternary Maps of marize three main topics of recent studies which Japan", IWATA(1987), KOAZE(1987) and KOAZE have not been treated by the review papers and IWATA (1987) synthesized the distribution of mentioned above: chronology of glaciations, glacial landforms and fossil periglacial features, snowline elevation, and permafrost distribution such as ice-wedge casts, cryoturbations and in Last Glacial age. block streams which had been reported before the middle the 1980's. II. Chronology of glaciations Fossil periglacial features were studied mainly Progress in tephrochronology supports in Northern Japan, although some were reported chronological research on glacial deposits in from the southwestern part of the country. Japan. Before the 1980's, only a few moraines Process-oriented research into present were dated by the marker tephra which were periglacial actions in the alpine belt of the occasionally exposed in outcrops of glacial and Japanese high mountains is another important fluvioglacial deposits. During the 1980's, many field closely connected to Quaternary periglacial researchers began to dig trenches into moraine

1) Received 30 April 1991. Accepted 24 May 1991. 2) Graduate School of Environmental Science, Hokkaido University, 060 Sapporo. 204 The Quaternary Research Vol. 30 No. 3 July 1991

at an altitude of about 1,750m, (Fig. 1) represent the Ichinomata stage. ITO and MASAKI (1989) found pumice E from Tateyama Volcano, labeled EPm, in a trench on the lowermost moraine ridges (point J in Figure 1), although they did not find it on other moraine ridges (points A-K in Figure 1). Since EPm directly covers the till of the lowest moraine, they concluded that the outermost ridge of the Ichinomata stage was formed just before the fall of EPm, which was dated about 60ka by MACHIDA and ARAI (1979). This was the first occasion in the Northern Japan Alps, when the age of moraines was determined directly from marker tephra. MACHIDA and ARAI (1979) thought that the till of the Murodo Glacial antedates the fall of DKP in the Mt. Tateyama area. However, as ONO (1980) commented, the stratigraphical relation between DKP and the Murodo Glacial till cannot be determined in the field. The glacial advance corresponding to the Ichinomata stage (named the Yokoo Glacial: IOZAWA, 1962, and including the Babadaira stage) is widely recognized in the Japanese high mountains (Table 1). It is called the Nishimata stage in the Mt. Kashimayari area (ITO and Fig. 1 Trench sites (A-J) on the terminal MASAKI,1987), the Iwatake stage in the Mt. moraines of Ichinomata stage, in Shirouma area (KOAZE et al., 1974), the Murodo Yarisawa and Yokoo Valleys, Mts. Glacial on Mt. Tateyama (FUKAI, 1975; MACHIDA Yari-Hotaka area, Northern Japan and ARAI 1979; ONO, 1980), the Nakagosho Alps stage I and II in the Central Japan Alps (after ITO and MASAKI, 1989). (YANAGIMACHI, 1983) and the Poroshiri Glacial (Stade) in the Hidaka Range in Hokkaido (ONO ridges, even where there are no outcrops. and HIRAKAWA, 1975). The Northern Japan Alps, where Quater- This significant glacial advance represents a nary glaciation was the most extensive in Japan, cold phase of oxygen isotope stage 4. The and where the marker tephra from Daisen, Aso glacier extended much further downstream in and Tateyama Volcanos cover wide areas of the this stage than in a later one, corresponding to glaciated terrain, provide the most favorable isotope stage 2, in the Japanese high mountains. fields for such studies. The reason why the glacier attained its maxi- In the Mts. Yari-Hotaka area, ITO (1982) mum extension in stage 4 in Japan is because of recognized four glacial stages in the Gamata more favorable surface temperature conditions Valley: Takidani, Yaridaira, Hidazawa I and of the Japan Sea for generating snowfall (ONO II, from older to younger, respectively. They and HIRAKAWA, 1975; ONO, 1984b): the warm correspond to the Ichinomata, Babadaira, and Tsushima current still flowed into the Japan Sea Yarisawa I and II stages in the Yarisawa Valley in stage 4, while it did not in stage 2 because of (ITO and VORNDRAN, 1983). the sea level lowering. However, analyses of Well preserved lowest terminal moraine ridges deep sea cores obtained in the southern part of 1991年7月 第 四 紀 研 究 第30巻 第3号 205

Table 1 Tentative chronological table of mountain glaciations in Japan

the Japan Sea demonstrate that the warm and SHIMIZU, 1982; ONO, 1984a; YANAGIMACHI, current did not enter the Japan Sea between 1983). about 60 and 8ka (ARAI et al, 1981). The glacial advance corresponding to isotope ONO (1988) suggested that the sea surface stage 2 is called the Karasawa Glacial in the Mts. temperature became cooler in stage 2 than in Yari-Hotaka area (IOZAWA, 1962), the Kitamata stage 4. The decrease in sea surface tem- stage in the Mt. Kashimayari area (ITO and perature diminishes the evaporation from the MASAKI,1987), the Tateyama Glacial in Mt. sea surface, minimizing snowfall from the Tateyama (FUKAI,1975), the Nakagosho III in winter monsoon. There is also a possibility the Central Japan Alps (YANAGIMACHI, 1983) that sea ice covered the surface in the northern and the Tottabetsu Glacial (Stale) in the part of the Japan Sea, according to the indicated Hidaka Range (ONO and HIRAKAWA, 1975). sea surface temperature. In the Mts. Yari-Hotaka area, the Karasawa The beginning date for the stage 4 glacial Glacial is subdivided into two substages called advance is still unknown, but it probably Hida (Hidazawa) I and II. In the Mt. Shiro- postdates 70ka, for ITO and SHIMIZU (1987) did uma area, KOAZEet al. (1974) recognized three not find Aso-4 pumice (from Aso Volcano in substages corresponding to the advance of stage Kyushu; dated by fission track method to 2: Akakurazawa, Kanayamazawa and Shirou- 70ka) on the moraine ridge of the Iwatake stage, mazawa, from older to younger. The till of the while it covers the older moraine of the Akakurazawa substage gave a 14C age of Yoshiwara stage. 25,150±210 years B.P. The end date of the stage 4 glacial advance In the Hidaka Range, pumice A of Eniwa seems to be around 55ka, because pumice IV of Volcano (En-a, dated about 15-18ka) is inter- Ontake Volcano (PmIV), whose fall age is esti- calated in the outwash deposits of the Tottabetsu mated about 55ka, directly covers the Nakagosho Stade (ONO and HIRAKAWA, 1975). As the till of stage moraine in the Central Japan Alps (ONO this stale is covered with pumice D of Tarumae 206 The Quaternary Research Vol. 30 No. 3 July 1991

Fig. 2 Changes of morphogenetic environments in the Japanese high mountains since the middle Pleistocene

Uplift rates of mountains: A and B: 2mm/year, C: 1mm/year, D: 0.5mm/year. snowline I: snowline elevation in Pacific side, snowline II: snowline elevation in Japan Sea side, Large figures apply to Japan Alps, Central Honshu, and small ones to Hokkaido. (after KOAZE,1988)

Volcano (Ta-d, dated about 9,000 years B.P), is about 100ka (MACHIDA, 1980), the exact age the deglaciation of stage 2 occurred between 15 is still not clear. Table 1 shows, therefore, and 9ka in the Hidaka Range. two possible chronological positions for The existence and extent of older glaciations in the Chogatake Glacial, the Otanihara and the Japanese high mountains are still in debate. Yoshiwara stages. SAKAGUCHI (1988) suggested However, a glacial advance prior to stage 4 is that they correspond to isotope stage 5d. verified in the Northern and Central Japan An older moraine found in the Kurokawa Alps. Valley, Central Japan Alps, is also covered In the Northern Japan Alps, ITO (1983) with a reddish-colored weathered volcanic ash proposed the Chogatake Glacial on the basis of (ONO and SHIMIZU,1982; ONO, 1984a). This dissected cirque, till and outwash deposits moraine seems to correspond to the older around Mt. Chogatake in the Mts. Yari-Hotaka glaciations in the Northern Japan Alps. area. The outwash of the Chogatake Glacial is KOAZE(1988) proposed multiple glaciations in directly covered with pumice D of Tateyama the Japanese high mountains. Under the Volcano (DPm). ITO and MASAKI(1987) also assumption that the Japan Alps were found DPm in a trench on the lowest terminal continuously uplifted at a rate of 2mm/y, they moraine, called the Otanihara moraine, in the would undergo at least four or five glaciations Mt. Kashimayari area. Between the DPm (lines A and B in Figure 2). SCHLUCHTER et al. horizon and the Otanihara stage till, a weathered (1981) also postulated multiple glaciations ash of 10cm thickness is intercalated. which date back to the middle Pleistocene in the In the Mt. Shirouma area, ITO and SHIMIZU Northern Japan Alps, although their report (1987) dug a trench on the lowest moraine ridge, lacks a detail description of glacial landforms called the Yoshiwara stage (KOAZE et al., 1974): and deposits. a dark reddish-colored (5Y7/1) weathered III. Snowline elevations of volcanic ash directly covered the till of the the Last Glacial age Yoshiwara stage, and they did not find DPm on it, although they did find Aso-4 and EPm. As stated in the previous section, the alpine Although the estimated age of the DPm glaciation was most extensive in the Japanese 1991年7月 第 四 紀 研 究 第30巻 第3号 207

Fig. 3 Last Glacial snowline elevation in Eastern Asia mountain and range

[Qinghai-Xizang Plateau] Q: Qilian Shan, QN: Qinghai Nanshan, A: Anyemaquen, T: Talidashan M: Mahan Shan, Qr: Qier Shan, Gg: Gongga Shan, Dc: Diancang Shan [Easten China] Tb: Taibai Shan, W: Wutai Shan [Formosa] X: Xue Shan, Y: Yu Shan [Northeast China] Hu: Huanggangliang, Dp: Dapingling [Japan] SJ: Southern Japan Alps (Akaishi Range), CJ: Central Japan Alps (Kilo Range), NJ: Northern Japan Alps (Hida Range), I: Iida San, G: Gassan, HC: Hayachine San, H: Hidaka Range, D: Daisetsu Zan, R: Rishiri Dake, [South Korea] S: Seolag Sun, C: Chiri San, [North Korea] K: Kwanmom San [Soviet Union] Ty: Gora Tardoki Yani Last glacial coastiline corrseponds to the-100m isodepth. Isodepth in the Yellow Sea is based on the Sea botton topographical map of Bo Hai and Huang Hai (1/100,000) of the First Ocean Institute of the Chinese Oceanographical Agency (1984). (after ONO, 1988). 208 The Quaternary Research Vol. 30 No. 3 July 1991 high mountains in isotope stage 4 (or 5d) of the snowline elevation increases in the Daisetsuzan Last Glacial. ONO (1988) reconstructed the area in Central Hokkaido. This implies that the snowline elevation during stage 4 in eastern Asia glaciation in Central and Northern Hokkaido (Figure 3). The glacial chronology and was weakened by winter dryness caused by the maximum glacier extent are not as clear in sea ice cover on the northernmost part of the China, Korea and the Soviet Union as in Japan. Japan Sea. Therefore, the snowline elevation on the continent is represented by the glaciation limit. IV. Permafrost distribution in The snowline elevation of Quilian Nanshan, the Last Glasial age Mahanshan and Wutaishan are estimated from On the basis of studies of fossil periglacial the author's observations, and others are phenomena in Japan and China, ONO (1990) estimated from various papers published in tentatively described the permafrost distribu- China, the Soviet Union and Japan (cited in ONO, tion for the Last Glacial age in the north and 1988). eastern Asia (Figure 4). Figure 3 illustrates the following four im- Although there are several reports of ice- portant characteristics of snowline elevation wedge casts in Hokkaido, only one found near distribution in the Last Glacial age in eastern Wakkanai, northernmost Hokkaido (KOAZEet Asia: al., 1974), is a definite one. Other features (1) Snowline elevation increases abruptly at which are shallow in wedge depth, and narrow in the eastern margin of the Qinghai-Xizang wedge opening, look more like soil wedges. Plateau. This reflects both the high elevation Figure 4 also shows that the present soil wedge and the dryness of the Plateau. distribution is concentrated on the southern (2) Snowline elevation becomes higher inland, margin between the continuous permafrost zone and lower near the Pacific Ocean. An isobase of and the discontinuous zone. This implies that the snowline elevation of 3,400m is determined Hokkaido was located in such a transitional zone from snowline data from Mts. Taibaishan, between continuous and discontinuous perma- Xueshan and Yushan. This isobase demon- frost. strates no possibility of Quaternary glaciation in The finding of palsa on the summit (area) of the Mt. Lushan (1,474m high) area in South- Mt. Daisetsuzan (TAKAHASHI and SONE, 1988; east China. SONE et al., 1988) proves that the alpine (3) A zone of lower snowline elevation (a permafrost there is part of the discontinuous snowline "trough") stretches from Formosa belt. On the basis of the year round air towards the mountains of the Japan Sea side of temperature measurement on the summit area of Japan. The snowline elevation inclines Mt. Daisetauzan, SONE(1991) estimated that abruptly from the Pacific side to the Japan Sea the lower limit of the discontinuous permafrost side: it is 2,700m in the southern part of the belt is 1,500m. Southern Japan Alps, but only 2,200m in the This estimate suggests that the whole of southern part of the Northern Japan Alps. Hokkaido was in the discontinuous permafrost The inclination is 5×10-3 toward the northwest. zone during the Last Glacial age, if in the fact the In the northern part of the Northern Japan alpine permafrost belt was lowered by 1,500m, Alps, the snowline descends abruptly with an which corresponds to the maximum snowline inclination of 1.5×10-2 toward the northwest. depression. The continuous alpine permafrost This indicates that the climatic contrast belt which is estimated to extend over 2,200m on between the Pacific and Japan Sea sides, which Mt. Daisetsuzan, descended to 700-800m in characterizes the present winter monsoon elevation in Hokkaido and to about 2,200m in the climate in Japan, also existed in the Last Glacial Japan Alps. age. Acknowledgements (4) The snowline trough continues to the southern part of the Hidaka Range, while the Field researches in the Quilan Nanshan, 1991年7月 第 四 紀 研 究 第30巻 第3号 209

Fig. 4 Present and Last Glacial permafrost environments in Eastern Asia

1. continuous permafrost zone, 2. southern limit of discontinuous permafrost, 3. southern limit of sporadic permafrost (only indicated in northeast China), 4. southern limit of seasonal freezing of 50cm depth in China, 5. southern limit of seasonal freezing zone, 6. Last Glacial southern limit of continuous permafrost zone, 7. Last Glacial southern limit of discontinuous permafrost zone, 8. Last Glacial alpine permafrost (continuous zone), 9. present distribution of active soil wedges (after ROMANOVSKIJ, 1985), 10. city (B: Beijin, C: Changchun, D: Datong, H Harbin, Q: Qiqihar, X: Xian) (after ONO, 1990) 210 The Quaternary Research Vol. 30 No. 3 July 1991

Mahanshan and Wutaishan were greatly significance of the Late Pleistocene marker tephra on assisted by Profs. WAN NAILIANG and CUI ZIJIU, the lowest terminal morainein the Yari-Hotaka Beijin University, and Profs. LI JIJUNG,CHANG Range, Northern Japanese Alps. Chirigaku-hyoron LINGYUANG, Lanzou University, and Prof. SHI (Geographical Review of Japan), 62A, p. 437-447. YAFUNG,Lanzou Institute of Glaciology and IWATA, S. (1987) Periglacial phenomena. In Japan Association for Quaternary Research (ed.): Cryopedology. The author wishes to express Explanation text of Quaternary Map of Japan. his deep thanks to them. Partial field research 119p., Tokyo Univ. Press, p. 46-51. expense was aided by Tokyo Geographical IWATA, S. (1989) Cryogenic weathering and periglacial Society, and the study of reconstruction of Last slope processes in Japanese high mountains. Chikei Glacial permafrost environments was supported (Transactions, Japanese Geomorphological Union), 10A, by Grant-in-Aid for Scientific Research on p. 67-75. Priority Areas, the Japanese Ministry of KOAZE, T. (1984) Glaciation in the Japanese high Education, Science and Culture (No. 01643001; mountains; a Reviews. Chigaku-zasshi (Journal of chief: Prof. T. AKAZAWA, Tokyo University). Geography), 93, p. 428-435. KOAZE, T. (1987) Mountains and glaciations. In Japan References Associatin for Quaternary Research (ed) Explana- tion text of Quaternary Map of Japan. 119p., Tokyo ARAI, F., OBA, T., KITAZATO, H., HORIBE, S. and MACHIDA, Univ. Press, p. 39-46. H. (1981) Late Quaternary tephrochronology and KOAZE, T. (1988) Morphogenetic environments of paleo-oceanography of the sediments of the Japan Japanese mountains in the Late Quaternary. The Sea. Daiyonki-Kenkyu (The Quaternary Research), Quaternary Research (Daiyonki-Kenkyu), 26, p. 255- 20, p. 209-230. 263. FUKAI, S. (1975) Glaciation and its age in the Northern KOAZE, T., NOGAMI, M. and IWATA, S. (1974) Ice-wedge Japanese Alps. In M. SHIKI(ed.): Nihon no hyouki casts in eastern Hokkaido, Japan. Chigaku-zasshi no shomondai (Problems of ice ages in Japan). 206p., (Journal of Geography), 83, p. 48-60. Kokon-Shoin, p. 98-111. KOAZE, T., SUGIHARA, S., SHIMIZU, F., UTSUNOMIYA, Y., IOZAWA,T. (1962) On the lowest moraine in Mts. IWATA, S. andOKAZAWA, S. (1974) Geomorphological Yari-Hotaka area. Chirigaku-hyoron (Geographical studies of Mt. Shirouma. Sundaishigaku (Sundai Review of Japan), 35, p. 652-653. Historical Review), 35, p. 1-86. ITO, M. (1982) Glacial geomorphology around the KOAZE, T. and IWATA, S. (1987) Glacial and periglacial Migimata, Gamata Valley, Northern Japanese Alps. phenomena. In Japan Association for Quaternary Chigaku-zasshi (Journal of Geography), 91, p. 88-103. Research (ed.): Explanation text of Quaternary ITO(1983) Glacial landforms and accumulation terraces Map of Japan. 119p., Tokyo Univ. Press: p. 74-79. around Mt. Chogatake, the northern Japanese Alps, MACHIDA, H, and ARAI, F. (1979) Daisen-Kurayoshi Central Japan. Chirigaku-hyoron (Geographical Review Pumice: stratigraphy, chronology, distribution and of Japan), 56, p. 35-49. implication to Late Pleistocene events in Central ITO, M. and VORNDARAN, G. (1983) Glacial geomorphol- Japan. Chigaku-zasshi (Journal of Geography), 88, ogy and snowlines of younger Quaternary around p. 313-330. the Yari-Hotaka Mountain Range, Northern Alps, ONO, Y. (1980) Glacial and periglacial geomorphology Central Japan. Polarforschung, 53, p. 75-89. in Japan. Progress in Physical Geography, 4, p. 149- ITO, M. and SHIMIZU, F. (1987) Discovery and (its) 160. significance of the marker tephra covering the ONO, Y. (1982) Reconstruction of the amount of moraines in the Matsukawa-Kitamatairi, east of snowfall in the Last Glacial age by glacial landforms Mt. Shirouma. Chigaku-zasshi (Journal of Geography), and sea-level changes. The Quaternary Research 96, p. 112-120. (Daiyonki-Kenkyu), 21, p. 229-243. ITO, M. and MASAKI, T. (1987) Glacial landforms and ONO, Y. (1984a) Quaternary glaciations in the Pleistocene glaciation in the Ohtsumetazawa Valley, Japanese high mountains morphological and southeastern part of the Mt. Kashimayari, Ushiro- chronological problems. IUGS-UNESCO Interna- tateyama Mountain Range, Northern Japanese Alps. tional Correlation Program, Proj. 73/1/24. Quaternary Chirigaku-hyoron (Geographical Review of Japan, 60A, Glaciation of Northern Hemisphere, Report 8, p. 182- p. 567-592. 201. ITO, M. and MASAKI, T. (1989) Chronological ONO,Y. (1984b) Last Glacial paleoclimate reconstruct- 1991 年7月 第 四 紀 研 究 第30巻 第3号 211

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