Journal of Geosciences, Osaka City University Vol. 32, Arl. 4, p. 91-121 March, 1989
Stratigraphical Subdivision and Pollen Zonation of the Middle and Upper Pleistocene in the Coastal Area of Osaka Bay, Japan
Masakazu FURUTANI
(with 16 Figures and 2 Tables)
Abstract
In this study, the author clarified a standard stratigraphical succession ranged from Ma8 bed of the Osaka Group to the Nanba Formation in the offshore areas of Senshu and Kobe Port and onshore areas of Senshu, Osaka Port and Amagasaki City by means of pollen Stratigraphy, tephro chronology and absolute dating. The standard stratigraphical succession extending from the bot tom of the sea to ca. 200 m. depth in Osaka Bay, which intercalates ten marine or brackish clay beds, fou r volcanic ash layers and thirteen volcanic glass horizons, is divided into four pollen zones namely HaploxY/Ol1 Z., cf. Pseudotsliga Z., Lagerstroem£a Z. and Celtis-Aphananthe Z. and is subdivided thir teen pollen assemblage zones (P1 to PIS). Stratigraphical successions in lowland and upland areas of Osaka City, Higashi-Osaka City and Itami City are also reexamined by means of the same methods. The results of a synthetic correlation between submarine stratigraphical successions and low land and upland ones from the Middle Pleistocene to the Holocene are summarized in this paper. And then, on the basis of the standard stratigraphical succession, several problems concerning the correlation and subdivision are discussed.
1. Introduction
Osaka sedimentary Basin is filled by late Cenozoic sediments and surrounded by moutainous ares of basement rocks. The Basin itself is geomorphologically divided into hilly lands, terracelike uplands, lowlands and the bottom of Osaka Bay. In the hilly areas, the Pliocene-Pleistocene Osaka Group is divided into the Sennan Formation (lowermost part), the Kokubu Formation (lower part) and the Senpoku For mation (upper part) in ascending order. The Senpoku Formation is composed of al ternations of marine clay beds (Ma3, Ma4,···Ma9 and MalO beds in ascending order) and freshwater sediments (hIHARA, M. et al., 1975). In the upland areas, Middle and Upper Pleistocene Terrace deposits are distributed, and divided into High (the Harima and Kiyotani Formations), Middle (the Uemachi Formation) and Low (the Itami Formation) ones basing on the height of depositional surface above riverbed and the weathering degree (hIHARA, M., 1960). The Uemachi Formation is interbeded with a marine bed in Uemachi, Hirakata and Akashi areas. Under the ground in the lowland areas, late Cenozoic sediments are developed and 92 ~asakazu FURUTANI are divided into five stratigraphic units, the Alluvial formation, "the Upper Pleistocene formations", the Osaka Group, "the Infra-Osaka Group (early Pliocene)" and the Kobe Group (Miocene) in descending order on the basis of deep drillings namely OD-l,·· OD-9 (IKEBE, N. et al., 1970). Recently, YOSHIKAWA, S. et al. (1987) reveal that "the Infra-Osaka Group" and the Kobe Group in the OD-1 and OD-2 cores are assigined to the lower and lowermost parts of Osaka Group from lithologic and pollen stratigraphic data and a fission-track date. The information about "the Upper Pleistocene forma tions" is insufficient, and the stratigraphic correlation between Upper Pleistocene forma tions in upland and lowland areas is still open to discussion. "The Upper Pleistocene formations", which are ranged from the upper limit of MalO bed to the lower limit of the Alluvial formation (Nanba Formation), intercalates two marine clay beds, namely Mall and Ma12 beds at OD-1 site in Osaka Port (IKEBE, N. et al., 1970). Ma12 bed under the ground in the onshore areas is inferred to be cor related with the Itami clay bed in Itami upland (HUZITA, K. and MAEDA, Y., 1971) and the middle and upper parts of the Uemachi Formation in Uemachi upland (FURUTANI, M., 1978). The informations about late Cenozoic sediments under the bottom of Osaka Bay, has been insufficient, with the exception of that about the Alluvial formation. Recently, the lithologic and pollen successions of the strata ranged from Ma12 bed to Alluvial for mation in the "Port Island" of Kobe Port, were reported by FURUTANI, M. et al. (1983). HUZITA, K. and MAEDA, Y. (1984) also published the results of their research on the strata ranged from MalO bed to Alluvial formation in the same area. From 1981 to 1983 a synthetic research on the submarine strata ranged from the bottom of the sea to ca. 400 m. depth in offshore area of Senshu was carried out by NAKASEKO, K. et ai. (1984). They suggested that the strata ranged from the Osaka Group to the Alluvial formation is divided into the Sennan-oki Formation and the Kukojima Formation in ascending order. After then, SUGANO, K. et al. (1986) suggested that "Akagashi bed" in the Kukojima Formation is correlative with Ma9 bed in Minato-B site near OD-1 site, but the cor relation between the Sennan-oki and Kukojima Formations and OD-l column is still an outstanding question. In this paper, on the basis of lithological and pollen analytical investigations of the strata ranged Middle Pleistocene to Holocene in offshore and onshore areas of Osaka Bay, stratigraphical subdivision and pollen zonation are described in detail. Besides the stratigraphical successions are standardized and a synthetic correlation between coastal and inland areas is discussed.
II. Methods of study
1. Investigated areas and sites Columnar sections and pollen diagrams are represented by boring core samples which were almost obtained by surveys for foundation works in eight areas surrounding Stratigraphical Subdivision and Pollen Zonation 93
Osaka Bay. These areas which include thirty three sites III total are shown in Fig. 1. Owl site is the same locality as that of OD-1 in which IKEBE, N. et al. (1970) standardized the stratigraphical succession under the ground of Osaka Plain. On6 site is the stratotype of the Uemachi Formation (Middle terrace deposits).
Osaka Bay
C Alluvia/deposits [[[[IT] Middle 8 lower terrace deposits
~ Higher terrace·deposits ED Osaka Graup rOkm '-- ~I ~ Basement rocks
Fig. 1. Geologic map and investigated sites (simplified after ITIHARA et al., 1966). Ko: Offshore of Kobe Port, Am: Onshore and inland in Amagasaki and Itami City, On: Lowland and upland in northern part of Osaka City, Ow: Onshore of Osaka Port, Os: Lowland and upland in southern part of Osaka and Sakai City, Sw: Onshore of Senshu area, Sn: Offshore of Senshu area. 94 Masakazu FURUTANI
2. Preparation The procedure to preparate pollen slide samples for microscopic work is as follows: Dispersion by KOH solution, wet-sieving by 125 meshes (1/8 mm.), extraction of colloids, extraction of silicates, floatation of plant residues by heavy solution (gravity= 1.85), de hydration by acetolysis method and mounting of slide. So far, the extraction of colloidal clay grains smaller than pollen grains was a troublesome process in pollen analytical technique. The author made use of the vibrating micro-mesh filter which is possible to eliminate completely fine grains smaller than 5 ,/.tm. size in short time for this process.
3. Pollen zonation and correlation Pollen grains which are produced by trees and grasses are supplied from vegetations In river basins of hinterlands behaving like as silt grains (MULLER, J., 1959). Vegeta tional change caused by climatic change is shown as compositional change of pollen as semblage in sediments. Zonation of pollen compositional transition means to divide stratigraphic successions into characteristic pollen assemblage zones. In the case of the same sedimentary basin, each pollen compositional transition is expected to correspond to that in the different areas, so that the stratigraphic correlation is possible by means of pollen assemblage zones. For example, the N'anba Formation was divided into six pollen assemblage subzones which are correlative with the corresponding subzones in different three areas on the basis of characteristic dominant taxa (FURUTANl, M., 1979). Besides, volcanic glass horizon (Yoko-oji volcanic ash layer) were recognized in a pollen subzone. Furthermore, FURUTANl, M. (1984) showed that fourteen pollen assemblage zones ranged from the upper Osaka Group to the anba Formation are correlative with the corresponding zone in ten sites in offshore area of Senshu.
III. Stratigraphical subdivision and pollen zonation
1. Osaka Port area In Owl (OD-1 ; bored 907 m.) site, the Osaka Group ranged in depth from 115 m. to 690 m. is interstratified with eleven marine clay beds which are correlated with MaO, Ma1, ...MalO beds of the standard succession in hilly lands (IKEBE, N. et al., 1970). The deposits between the upper limit of MalO bed and the lower limit of the Nanba Formation which were named "Upper Pleistocene formations" by them, are interstratified with two marine clay beds namely Mall and Ma12 beds. TAl, A. (1966a; 1966b) divided the Osaka Group in Owl site into two pollen fossil zones i.e., lvletasequoia Zone and Fagus Zone. Furthermore, Fagus Zone vvhich is e quivalent to Ma3 to MalO beds was subdivived into four subzones i.e., E (including Ma3 bed and Ma4 bed), F (including MaS bed and Ma6 bed), G (including Ma7 bed and Ma8 bed) and H (including Ma9 bed) subzones (TAl, A., 1973). In Ow2 (Minato-B; bored 465 m.) site, its geologic column is correlated with the strata ranged from Ma3 bed to Ma12 bed in Owl site. "Azuki Tuff" interbeded in Stratigraphical Subdivision and Pollen Zonation 95
Ow2 ~ GL-. JF .,,- J' . . II ;fc'f~", t! I "'. ~qis! ~,;r#' ,,~,~ ~¢" q '" P,f.$- ~4'iJ I'}~ ",~" ~ .,~ }' ./' $'.0,; Jid' ... G *,(,;:!;f' c " "
"
d ~ - e f- P3 ------I- f- b I-
~ e P7 ~ ~
r- b ~ PV >- - ~ - ~ f-- 1=-- •
-,.. I- I'tO
- f-- i- ~ ... '" - f-- f- e - b -- PI' • ..... - -- - ~ .. a ,'. " - f- d
~ I- PI3 ~I- - >- - f-- f-- f-- e f-- l-
I--i--- I PI5 f-o I I r I!' f I
Fig. 2. Pollen diagram and zonation in site Ow2 in onshore of Osaka Port. Owl Ow2 Ow3 <0 Q) 10 (00-1 ) Geology POLLEN ASSEMBLAGE Correlation
~ lkebeet Toi Furutoni U GlolS c DOMINANT CHARACTERIS . al ~g u 0 (1978) 'X rY V> V> If. n.index N TAXA TAXA 119701 (1973) 09791 ~ Podocorpu5 -10 Oiplaxylon E Ma 13 bed ~B;~. Cosronops;s .~ F PI Cyc/obolonopsis " PI F Myrfco(ruoro type} -20 ~ . ·U514 Ouercus L Celrb'Apnonontfle 4 I-- ti'"1:520.1.524 f-- :r- erma -30 E I¢~*~ B. ----~------I-- f-- -40 Gye/aba/onops;s Abies TSU9Q c Mol2 I ~ P3 Oip/oxylon I Sciodopltys D B. b ~ Ouercus Foqus LoqerstroemJo -50 - ~ I- 5 '; PS Oiploxylon Fagus . cf.Pseudofsugo -60 E .. C I'" P7 c f--- P7 Diplexylon Tsugo ct Pseudo'sugo .e -70 ~ ~ - 1l I- ~ Mall DiplOJ(ylon ~ ., -80 Mallbed ~ P9 cf. Pseudorsugo .0; .B V> B. FoqLls ., ------A ~ ",. =.Cro 0:: I- ., -90 .•.. Z2 1.496-1.4913 Q; N Q. A c: ~ Q. ----- 9>~ alPIO f--.ll.. Piceo => '!j -11l0 ~ '-... ·· .. n PIO CUPRESSACEAE c ;0 XV O'~~.. 21 Crypromerlo c -:-;:~ ...... , -110 ). ~------~-. :1-.. I-- Z ):l, MaiO Haploxylon Hoploxy/on -120 MalObed PI I :!Pll!b B. ~ Tsuqo Cryptomaria ~ ... I-- :130 ''"6-6 nl-- c;(Q:' I -140 ~------I I--- Q. -- -- t ~ "~ to Cyc:/oba/anopsis Sc:iadopitys -150 Ma9 41,,13 ~ PI3 ~ Ma9bed B. DiplO}(ylon Haploxylon .. co . ~ TsufJo Cyc:/obalonopsis C;" -160 IC N" H ______.:: 3- ~~ ~ -170 "'" ~i ~ lL" -180 ~ I MoB Haplaxylon .:::::~ SI PiS DiplOKylon G •.•• Sol B. ~ FaQus -190 •
Fig. 3. Lithologic and pollen successions in onshore of Osaka Port. Stratigraphical Subdivision and Pollen Zonation 97
Ma3 bed is discovered in depth 412.6 m. A marine bed was newly revealed between Mall bed and Ma12 bed, and a volcanic ash layer (V4) was recognized between MalO bed and Mall bed (SUGANO, K. et al., 1986). The strata range from Ma8 bed to Ma12 bed are divided seven pollen assemblage zones namely from PIS Zone to P3 Zone as shown in Fig. 2. P13 Zone is particularly characterized by the dominace of Cyclobalanopsis in its lower part, and is equivalent to Ma9 bed in Owl site. PIO Zone is equivalent to fresh water deposits between MalO bed and Mall bed, and is characterized by the appear ance of Picea and Cryptomeria. P7 Zone is equivalent to a marine bed between Mall bed and Ma12 bed. In Ow3 site, Mall bed and Ma12 bed are correlated with ones in Owl site. The volcanic glass horizons are discovered in the middle and lower parts of Mall bed and in the lower and middle parts of Nanba Formation (FURUTANI, M., 1978). The strata which range from fresh water deposits below Mall bed to the Nanba Formation are divided into six pollen assemblage zones. P9 and P3 Zones in this site are correlative with the corresponding zones in Ow2 site as shown in Fig. 3. The pollen assemblages in the above-mentioned three sites, indicated that PIS, P13 and PI1 Zones are characterized by the continuous appearance of Haploxylon, P9, P7 and PS Zones are characterized by the appearance of cf. Pseudotsuga, P3 Zone is charac terized by the appearance of Lagerstroemia and Euphorbiaceae (cf. Sapium) and PI Zone is characterized by the appearance of Castanopsis, Myrica (M. rubra type) and Celtis Aphananthe. Besides, the dominance of Cyclobalanopsis is recognized in P13, P3 and PI Zones.
2. Onshore area of Senshu In the coastal area of Senshu, the deposits above 60 m. depth under the ground which is composed of alternating beds of sand, gravel and clay, are interstratified with six marine beds. The uppermost marine bed is correlative with the Nanba Formation. The strata which are ca. 100 m. in maximum thickness are typically divided into eight pollen assemblage zones in Sw3 and Sws sites as shown in Fig. 4a, b. The characteristics of pollen assemblages in PI, P3, P9, PIO and P13 Zones are identical with those of the corresponding zones in Ow2 site. P4 Zone between PS Zone and P3 Zone is characterized by the appearance of Cryptomeria and Picea. From PIS Zone to P3 Zone, remarkable taxa in pollen assemblages are Haploxylon (PIS ~ Pll Zones), cf. Pseudotsuga (P9 ~ Ps Zones) and Lagerstroemia (P3 Zone) in the same way as zones in Ow2 and Ow3 sites as shown in Fig. 5.
3. Offshore area of Senshu The deposits from the bottom of the sea down to ca. 400 m. depth are interstratified with fourteen marine or brackish clay beds, which were named the Senshu-Oki Group by NAKASEKO, K. et al. (1984) in offshore area of Senshu. They identified a volcanic ash layer at 190.5 m. depth in 56-9 site and one at 332.2 m. depth in Snl (57-30) site as "Azuki Tuff" in the Senshu-Oki Formation by means of X-ray and EDX analysis. Sw3 ~ GL-m o ~ '<:' 20 ~ ~., ~ +~ . +1- + + .,'" ~ ~ ~ ~ ~ + c PI I .,:-; ~ N ~ ~ + + l- I- i- +1- . + + C ~ /-:52% I- + + + + + 'Tj ~ + l""" + 1- ...... + + + b c: I c: +- i- io-, + + + + + + ".., "" + ~ +~ 1- .. + + + + F- ""- I- d +1- +1- I- ~ + I- + + + + p + + + r ~ l- I- I-- ""'" ""'" + + + + +1- i- l- '" I-- + I-- + + b c PI3 f"I 12 ~ p I:: l- i- + I-- + + + + + 13 + I=- + + + + + + + + + '""" 14 + """"" + + + I-=- + + + I-=- b 50 15 '"'"' ~ § I-- '" ~ l- I- 60 16 - I- """"- - + + + + b PI5 W HI% + < 0.5% Fig. 4a. Pollen diagram and zonation in Sw 3 site in onshore of Senshu. Stratigraphical Subdivision and Pollen Zonation 99 - 1'0 o::t l() en a.. 0.. a.. a.. a.. Q) "0 .0 .0 0 "0 0.0 0 + + + + + ++ + + + + + + + +++ + + + + + + nnr ,n n n ::i ..c '"c ~ ~~ ~ ~ lSl'" I III II • n~ 1III • I II. • + E I ~ Oil Oil Oil Oil --' Oil N ro ..- tn '-" I II I I IIIII I IIIIIIIII I IIIIIIIII I ! II ! IIIII I IIIIIII ! ! I 100 Masakazu FURUTANI POLLEN ASSEMBLAGE 41 Swl c DOMINANT CHARACTER 0 m N TAXA TAXA 9 .p I Diploxylon Celtls·,4phononthe '9 Sw5 20 I I I Sciadopitys I P2 Cryptomeria Sciadopitys 30 Alnus Sw4 -,-, Diploxy/on Cyclobalanopsis 1 P3 -.:--- Cryptomeria lagerstroemia Cryptomeria "II '0 -" P4 Alnus Picea Sw3 -- Diploxylon P5 Cryptomeria cf. Pseudotsuga Fagus ,0 Diploxylon cf. Pseudotsuga P9 Fagus Cryptomeria - 60 22 70 Diploxylon Haploxy/on PI I Cryptomeria Fagus Fagus _8 _ eo -g------ " Sciadopltys Cyclobafanopsis 90 " PI3 Cyclobalanopsis Podocarpus " Haploxylon Costanopsis 11 '00 -1.4. _ ------PI5 Cryptomerla Hoploxylon "0 " Fig. 5. Lithologic and pollen successions in onshore of Senshu. <>'" 'I <> - (\J r I I I I I I - ...... H . W~~ n + + + + .n ~ n J . .n I. n,," .n + •nn ~Rn ~ nn In~Rn , ++ + . ". '" n + + I ,I , , + , , I + I I , , + . + + .. + + + + + . . ! . H ~ + , + ,I I + ,; i i II .. .. , II "I: III -5i -' ~ _. ~ ~ ~ s ~ S & ~ S ~ ~ & ~ I" ,,, '" I,!,,! !!! I!,!,!,i, II."!",, ,I"""" ,I", "," ,i.", I! I! ,I,! t!!',,! I,,!!! II I! I! 11"!'!' II!! 11'" ,I,!,!,,! " I,! I!,!, " I!", J TP Geology Sn I Sn2 Sn3 Sn4 Sn5 POLLEN ASSEMBLAGE Correlation -HI OIl It) OIl .. NakR~~arlal '0 OIl It) c:: DOMINANT CHARACT. Ow I Eo 0 APPEARANCE ~ ~ -210 ..... 0 Fig. 7. Lithologic and pollen successions in offshore of Senshu. w 104 Masakazu FURUTANI The Kukojima Formation which was inferred to cover uncomformably the Sennan-Oki Formation, was divided eleven lithologic units namely from "Basal conglomerates" to "Akahoya bed", and was subdivided eight nannofossil zones i.e., from N1 to N8 Zones by them. Emiliania huxleyi first appears in the middle horizon of N5 Zone and Pseu doemiliania lacunosa last occurs in the middle horizon of N8 Zone (OKAMURA, M. and YAMAUCHI, M., 1984). The strata ranged from the bottom of the sea to ca. 135 m. depth in Sn5 (57-30) site, which are interstratified with seven marine or brackish clay beds, are divided into seven pollen assemblage zones namely from P9 Zone to PI Zone as shown in Fig. 6. On the basis of close investigations in the five sites, it is concluded that the strata range from the bottom of the sea to ca. 210 m. depth which are interstratified twelve marine or brackish clay beds, are divided thirteen pollen assemblage zones as shown in Fig. 7. The characteristics of pollen assemblages in PI, P3, P9, PIO, P13 and PIS Zones are identical with the corresponding zones in 01'.'2 site. P5 and P7 Zones are characterized by the appearance of cf. Pseudotsuga. P2 Zone between P3 Zone and PI Zone is characterized by the dominance of Picea. From P19 Zone to PI Zone, remarkable taxa in pollen as semblages are Haploxylon (P19~Pll Zone), cf. Pseudotsuga (P9~P5 Zone), Lagerstroemia (P3 Zone) and Celtis-Aphananthe (PI Zone) in the same way as zones in Ow2 and Ow3 sites. 4. Offshore area of Kobe In the reclaimed islands in offshore area of Kobe Port, the deposits above ca. 160 m. depth under the bottom of the sea, are interstratified with six marine or brackish clay beds. Three volcanic ash layers (VI ~ V3) and nine volcanic glass horizons (G1 ~ G9) are recognized in those strata in Ko 21 site as shown in Table 1. Thirteen radio carbon dates, which range from 14,050±280 y.BP to 55,700±3,300 y.BP, are determined by means of accelerator method and ,a-counting method in Ko21 site as shown in Table 2. The strata range from the bottom of the sea to ca. 160 m. depth are divided into seven pollen assemblage zones. Pollen zonation from P3 Zone to P9 Zone in Ko19 site is shown in Fig. 8. The characteristics of pollen assemblages in PI Zone and P3 Zone are identical with the corresponding zones in Ow2 and Ow3 site. P5, P7 and P9 Zones are characterized by the appearance of ef. Pseudotsuga. In these three zones, P9 Zone is most similar to the corresponding Zone which is equivalent to Mall bed in Ow3 site. Furthermore, G8 and G9 volcanic glass horizons are correlative with the volcanic glass horizons in the middle and lower parts of Mall bed in Ow3 site from the data of glass refractive index (1.498-1.501). Pollen assemblages in Ko12, Ko19 and Ko20 sites, are similar to the corresponding zones in Ko2l site as shown in Fig. 9. It should be notice that the deposits being equivalent to P2 Zone which is interstratified with a thin marine bed, are characterized by the dominance of Sciadopitys in their lower part and characterized by the dominance of subarctic forest pollens including Haploxylon and Picea in their upper part. Stratigraphical Subdivision and Pollen Zonation 105 Table 1. Volcanic ash layers and volcanic glass horizons in Ko2l site. Shape of glass is as follows: H-type is consisted large broken bubble wall, T -type is consisted fibrous bubble, H-type is intermediate between Hand T types after YOSHIKAWA, S. (1984). Name Depth TP - m. Specimen Refract. index Shape G 1 29.15- 29.45 glass I. 509 - I. 513 H G2 35.15- 35.45 glass I. 497 - 1.501 H G3 37. 15- 37.40 glass I. 499 - I. 501 H VI 96.40- 96.42 ash 1.514 - 1.516 C-H I. 534 - I. 544 V2 97.37- 97.39 ash 1.513 - 1.519 C-H G6 116.15-116.45 glass 1.498 C V3 125.10-125.13 ash I. 504 - I. 510 T G7 128.95-128.98 glass I. 495 - I. 499 H G8 153.15-153.18 glass I. 498 - I. 500 H G9 156.35-156.38 glass I. 498 - I. 501 H Table 2. Radiocarbon dates in Ko2l site. Specimen Depth Radiocarbon date Dating No. TP - m. (yr.BP) No. 1 34.15- 34.45 14.050± 280 NUTA-246 2 35.15- 35.40 19,01O± 410 NUTA-247 2' 35.15- 35.40 15.030± 210 1- 13950 3 38.15- 38.45 24.190± 790 NUTA-248 4 41. 15- 41. 20 25.170± 650 NUTA-249 4' 41.15- 41.20 24,060 ± 1, 400 1- 13951 5 49.15- 49.45 25.370± 680 NUTA-250 5' 49.15- 49.45 25. 090± 1850 1- 13592 6 55.15- 55.45 25.730± 630 NUTA-251 7-1 63.15- 63.45 50.600±2.400 NUTA-398 7-2 63.15- 63.45 55.700±3.300 NUTA-252 8-1 69.15- 69.45 37. OOO± 2. 600 NUTA-399 8-2 69.15- 69.45 40. 500± 3. 600 NUTA-253 Ko19 ~~ ~~t ..ZB ~ 125 " I ~ a P5 c 1-- 33 1- ttlt~tt f, " t t- 135 "37 ~ rlf t b'P7 .. .. ~ E-I- ~ a • 1 r ~ 145 " .. c .. ~ ~ ~ P9 .." ~ .. b l0t + <0.5% Fig. 8. Pollen diagram and zonation in site Ko19 in offshore of Kobe Port. fP m 10 Kol2 Kol9 Ko20 Ko21 Geology POLLEN ASSEMBLAGE Correlation DIATOM Walanabe Huzita· '"Q) Tuff,Glass Age DOMINANT CHARACTERIS '0 ~ Ecology eto!. Maeda -10 0 TAXA TAXA ~ N n:index 14C y.BP (1983) (984) >. POdOCOrDUS 0 ~ Diploxylon <3 -20 CosTonopsis OJ Ma>8r PI Cye/ob%nopsis Myrieolrubra type) ~ Ouereus .2 ~ ~9-1.513 Celtls'Aphononrhe Ia. -30 14,050 ~ ~7-1501 c ~ /9,010 ef.Lorix Betu/o 0 ~ 24,190 Hoploxylon Myrieo Igo/e Type) .g -40 1.499-1.50/ 25,170 Pieeo 02 Fr Songu/sorbo E Tsugo Geronium ~ c----M 25,370 Ouereus Menyonfhes '0 -50 a:i P2 ------'0 25,730 Sclodopifys '> ~ 03 Mo>Br Betulo ~ ~ ~ 0 Jugfons - CrypTomerio 0 .... ~ -60 ------Q) '0 ~ 55,700 Q; a. «> Seiodopifys Logerstroemio a. 0.- P4 Fr a. -713 A/nus EUPHORBIACEAE ~ ~ ! >. 0 Diploxy/on Cye/ob%nopsis <3 ~-80 Se/odopitys ~05 Mo>8r P3 Abies '0 Logerstroem/o 1.514-1.516 Tsugo ~ ~-90 ~ 1.534-1.544 EUPHORBIACEAE VI 0 Betu/o Geronium FTI1.513-1.519 Pieeo -100 Fr P4 COMPOSITAE 06 A/nus Hoploxyfon c a:i 0 = -110 Diploxylon ef. Pseudotsugo .~ ~ ~ 07 Br>Mo>Fr P5 ~ G6 Cryptomerio Celtls'AphononThe ~ u ~ ~ '0 -120 '0 ~ 0 - '0 V3 0 ~ Dip/oxyton .;; r-----rso4-1.510 ef. Pseudofsugo P7 Pieeo .~ -130 ~ 09 Br>Mo>Fr f---.G.r ~ ~ Tsugo Pieeo a ~ - -140 ~ Oiploxylon ef. Pseuaotsugo 0 ~~ . -.J -1Il ~ Br>Mo>Fr P9 Alnus Pieso ~~2 PII ~uo ~8-1.5OC Foqus Cryplomerio -150 ~ ot~ r.Q -.J.~ 1.49B-1.501 PIO Pieso Pieeo -160 Fig. 9. Lithologic and pollen successions in offshore of Kobe Port. 108 Masakazu FURUTANI S. Onshore area of Amagasaki In the coastal area of Amagasaki, the deposits above ca. 6S m. depth under the ground, are composed of Ma12 bed, the Tenma Formation and the Nanba Formation (FURUTANI, M., 1978). They are divided into three pollen assemblage zones i.e. PI, P2 and P3 Zones. IV. Standard stratigraphy in the coastal areas I. Marine and brackish beds As mentioned above, marine and brackish beds which fill the role of key marker III the case of subdivision and correlation are interstratified with freshwater deposits. These beds are as follows; six beds ranging from Ma8 bed to the Nanba Formation exist in onshore area of Osaka Port, six beds exist in onshore area of Senshu, twelve beds exist in offshore area of Senshu, six beds exist in offshore area of Kobe Port and two beds exist in onshore area of Amagasaki. Ma9 bed, MalO bed, Mal2 bed and the middle part of the Nanba Formation are abundant in marine microfossils in Ow2 site (SUGANO, K. et al., 1986). On the other hand, in offshore area of Kobe Port four beds with the exception of Mal2 bed and the Nanba Formation are rich in brackish and freshwater diatoms. Pollen assemblage zones i.e., PIS, P13, Pll, P9, P7, P3 and PI Zones are equivalent to brackish or marine beds in those areas. PS Zone is also equivalent to a brackish bed in offshore area of Kobe Port. 2. Volcanic ash and absolute age Although more than twelve volcanic ash layers or glass horizons are recognized in the strata in onshore and offshore areas, traceable ones are limited to two or three as shown in fig. 10. A volcanic glass horizon in the lower part of Mall bed in Ow3 site is correlative with G9 horizon in K02l site and a horizon in the lowermost part of a maine bed being equivalent to P9 Zone in SnS site. A volcanic ash layer in the middle part of a marine bed between Mall bed and Ma12 bed in Ow2 site is correlative with V3 layer in K02l site and a horizon in the middle part of a marine bed being equivalent to P7 Zone in SnS site. G3 glass horizon in K02l site is correlative with a glass horizon in coaly bed which was determined as 22,900±2,070 y.BP by radiocarbon dating, being equivalent to g Subzone in P2 Zone in SnS site. G3 glass horizon in K02l site is cor relative with Heian-jingu volcanic ash layer (YOSHIKAWA, S. et al., 1986) judging from refractive index of glass and its absolute age. G 1 glass horizon in K02l site which is correlative with Yoko-oji volcanic ash layer (YOSHIKAWA, S. et al., 1986) is widely dis tributed in the middle lower part of the Nanba Formation. The first appearance of Emiliania huxleyi, which is assigned to an age of 270,000 y.BP, was recognized in the middle horizon of a marine bed which is equivalent to Pll Zone in offshore area of Senshu (NAKASEKO, K. et al., 1986). Radiocarbon dates of the Stratigraphical Subdivisiol1 al1d Pollen ZOl1atiol1 109 Sn Sw Ow Am Ko STANDARD ZONING PI PI Pig PIS PI5 PI? ~ Cycfobafonopsis dominant Zone PI9 [lIIJ Plceo dominant Zone - Tuff - Glass Fig. 10. Correlation by pollen zones in offshore and onshore areas in Osaka Bay. deposits corresponding to P2 Zone in offshore area of Kobe Port, are determined as the details are described later. 3. Pollen stratigraphy According to pollen stratigraphical study, four remarkable taxa are found in Middle and Late Pleisticene and Holocene deposits in the coastal area of Osaka Bay. They are Haploxylon, d. Pseudotsuga, Lagerstroemia, Celtis-Aphananthe. It is possible to divide the deposits into four stratigraphical zones besed on their characteristic appearances as shown in Fig. 10. Haploxylon in zones ranged from Pll Zone to P19 Zone should be distinguished from the same genus of subarctic forest element, whereas Haplo:xylon in PIa Zone, P4 Zone and the upper part of P2 Zone should be excepted from these zones because of the dominance of subarctic forest pollens e.g. Picea. The former Haploxylon, which increase together with warm temperate forest pollens e.g. Cyclobalanopsis, is as sumed to correspond to Pinus subgen. Haploxylon armandi (MINAKI, M., 1983), and the 110 Masakazu FURUTANI STRATIGRAPHY POLLEN ASSEMBLAGE III ~ .~ ....0 u c .D DOMINANT CHARACTERISTIC 0'" ::> ~ Tuff,Gloss Age N U1 TAXA TAXA '4C y.9P ~ d Dip/oxylon Cryplomerio Q) ~/ C ~ u; Castanops;s Q) 05U g e Cyc/aba/cnops;s Podocarpus () o ~ <: c Myrico(rubra Iype) 0 ~ ,,0 PI 0 " .... b Ouercus Cyc/aba/onopsi Celtls"Aphananthe I ~ /"': 05M GI .~ ;; FOQus Quercus f-- f---05L u a Ouercus 104,050 f--- I-G2 i Hop/oxy/on c(.Larix Be/ula f---G3 19,010 I Piceo Tsugo Myrica(gale type) f---G4 d Quercus Songuisorba 25,370 I- ~ P2 lID e Sclodopltys Betula Jug/ans ~ f---G5 ~,700 b Logers/roemlo 5 Alnus []]] .... a Scladap/lys EUPHORBIACEAE e nus r omena c a a s Cyclobolonopsi~ Mal2 ~ d Tsugo Podocorpu5 P3 e Dip/oxy/on Fogus Ulmus Logersrroemlo = I Dip/oxy/on Abies bed ~ '"0 b Looers'roemio .~ -.J a Alnus Ouercus Ulmus '//. VI ~ V2 e Piceo stula Sanou/sorbo 2 P4 b Picea Cryptomerla Alnus OLEACEAE ~ a Diploxylon Foous rYlJfomeria c ~ Diploxy/on FaQus cf Pseudotsuga u b 0 P5 f---G6 a A/nus CrYP'omerlo Afnus '.Ci: d Alnus UPRESSACEAE Diploxylon cf Pseudotsuga ~ V3 c Dip/oxy/on Hop/oxylon Hoploxylon MaS ~ PI5 b Cryptomer;o Cryplomerlo bed ~ ~ a Fogu.s Crypfomerlo Hap/oxy/on Fig. 11. Standard succession in offshore and onshore areas in Osaka Bay. Stratigraphical Subdivision and Pollen Zonation 111 latter is assumed to correspond to Pinus subgen. Haploxylon Iwraiensis P13 Zone which is equivalent to Ma9 bed in Ow2 site is characterized by the re markable dominance of Cyclobalanopsis in its lower part. P3 Zone and PI Zone are also characterized by the dominance of Cyclobalanopsis accompanied by Podocarpus and Ca.s tanopsis in their middle part. On the basis of the above mentioned evidences in lithology, chronology and pollen stratigraphy, it is possible to correlate twelve pollen assemblage zones with those in five coastal areas of Osaka Bay. The standard stratigraphy from the Middle Pleistocene to the Holocene is summarized as shown in Fig. 11. V, Stratigraphic correlation 1. Stratigraphic correlation between coastal areas and 'inland areas Stratigraphic subdivision and pollen zonation in inland areas was studied in the Uemachi upland (On6 site) and the Itami upland (Am2~4 sites) by FURUTANI, M. (1978), in the Kawachi lowland (HoI and 2 sites) by FURUTANI, i\'l. (1979) and is newly studied in the southern part (Osl ~ 3 sites) and in the northern part (On 1 ~ 5 sites) of Osaka City by means of the same method. The results of pollen zonation and stratigraphic correlation between coastal areas and inland areas are summarized as shown in Fig. 12. Several problems on stratigraphic subdivision and correlation are discussed as fol lowings. 1-1. The uppermost part of Osaka Group, the Middle Pleistocene Ma9 bed under the bottom of Osaka Bay is particularly characterized by the domi nance of warm temperate forest pollens including Podocarpus, Castanopsis and Cyclo balanopsis. Ma9 bed should be taken notice as a remarkable marine key bed in the upper part of Osaka Group, because of its pollen assemblage. On the other hand, MIKI, S. et al. (1957) reported the warm temperate forest plant remains composed of Myrica rubra, Quercus subgen. CyclobaLanopsis glauca, Q. phil Iyraeoides, Distyllium racemosum, Sciadopitys verticilata and so on at Uegahara in Nishino miya hills. In Hirakata hills, the plant remains composed of Quercus subgen. Cyclobalanop sis gilva, Syzygium buxifolium and so on were found in Shinkori bed (TAKAYA, Y. and ITIHARA, M., 1961) and a pollen composition including Cyclobalanopsis were reported In the same. bed (TAl, A., 1963). ITIHARA, M. et al. (1966) correlated "Syzygium bed" in Hirakata hills with MaS bed in the Osaka Group. The pollen composition in Ma9 bed (P13 Zone) in coastal areas is similar to the composition of plant remains at Uegahara namely "Syzygium Flora" (KOKAWA, S., 1961), whereas the pollen composition in MaS bed (PIS Zone) under the ground is characterized by the dominance of Fagus and Cryptomeria. Accordingly, the horizon of "Syzygium Flora" is not correlated with MaS bed, but with Ma9 bed under the ground. The pollen compositions of P14 Zone between MaS bed and Ma9 bed and of PlO r-- - U~lsnore ~rea STANDARD SUCCESSION Offshore Area Onshore Area Southern Part Higashi- Osaka Port Northern Part I\magasaki ~ltamj C. of Kobe Port c 01 Senshu 01 Senshu 01 Osaka C. Osaka C of Osaka C. Portisland Rokkoulsland '"o (0"-/) (Sn) (S"-/) (Os) (1-10) (On) (ArTl) (Ko) 'u'" C £J 100-11 o (f Tuff,Glass Age N (f) 2 3 4 5 1 2 3 4 5 I 2 3 4 I 2 3 I 2 3 4 6 I 2-4 10 12 13 19 20 21 ~L I--r--r-- PI r-- t-- PI PI PI PI PI PI PI PI I PI PI PI PI PI PI PI PI r-- I-e-- lEz~ r--c-- P2 r- P2 P2 P2 P2 P2 t- P2 P2 t- 1-1-- .ci r--- /: I--r-- P3 P3 "--153 P3 ~I-- ~ ~P3 Mal2 ~ r-- Mol2 P3 f-- r-- P3 n := P3 P3 ul-- P3 P3 P3 ~f-- bed P3 bed r---- '--I-- ~f- 'E~ f---~~ ~ ~ lE11-t--.'3 l- r-r--r-- ~'P4 t--tp""4 rt-- P4 ~ ~r--~ 1--1- ~ 1--1- I- I- r- r-- P51~ P5 P5 P5 P5 P5 f---G6 r--~f ~ f-t= t-- t-- t-~t- f-I-- f="1= t--f=..-- 1= 1= ~ I-- f- en f---V3 P7 r-- f-- P7 P7 P7 P7 ~~ ~ t--G7 5 P7 r;- P7 P7 :::;-- '" rc- t--t- r--- III g,1--~t- t--I- r-- f- I- I- I- f- t-- N ~ ~ P8 P8 ~ I-- r-r- t-- I- ~ r-I- I- I- r- ] 1--7t C Q l- P9'pg P9 I-- ::c Moll tpgl-- P9 P9 C P9~ r- P9 P9 t--+---+---1P9 r---- P9 I---i-- P9 f- ..., bed f---GB I Moll P9t-- P9 ~ f---G9 .. t-;;- bed f--- r- I--t r-- 3 f---V Zone between MalO bed and Mall bed are composed of subarctic and cool temeprate forest pollens which may be correlative with "Kitashinoda Cold Age" (Komyoike Re search Group, 1971) and "Hojyo Cold Age" (ITIHARA, M. et al., 1986). 1-2. Mall bed Mall bed which was included in "Upper Pleistocene formations" was usually prop osed to correlate with the High terrace deposits. In offshore areas of Kobe Port and Senshu, the strata between the upper limit of Mall bed and the lower limit of Ma12 bed interstratify two brackish or marine clay beds which are equivalent to P7 Zone and PS Zone. Mall bed and these two marine beds in Senshu are similar to those in Kobe Port in thickness and sedimentary facies respectively. Therefore these marine beds should be discriminated stratigraphically one another. The author proposes to name the three beds Mallcil bed, Mall(2) bed and Ma11(3) bed in ascending order. The High terrace deposits, which are widely developed in Akashi and Harima hills, are suggested to intercalate a marine bed namely Takatsukayama clay bed or Akasaka clay bed. However the pollen composition of the marine bed is not similar with one of MallCl)~MallC3) beds. The correlation of the High terrace deposits between hilly area and coastal area should be dscussed later. 1-3. Middle terrace deposits The Uemachi Formation in the Uemachi upland where is stratotype of the Middle terrace deposits is lithologically subdivided into the lower gravel, the middle marine clay and the upper silty sand members (FURUTANI, M., 1978). ITIHARA, iVI. (1960) clarified the compositional transition of plant remains changed from subarctic forest remains in the lower part to temperate forest remains in the middle marine part in the Hirakata formation. In the same manner, KOKAWA, S. (1961) re ported the plant remains including Pinus subgen. Haploxylon koraiensis, Menyanthes trifoliata and so on in the lower part of Uemachi Formation in southern part of Osaka City. The lower gravel member of the Uemachi Formation unconformably covers Mall bed and the upper part of Osaka Group, and its pollen assemblage is characterized by the dominance of subarctic forest pollens in northern (On6 site) and southern (Osl, 4 sites) parts of Osaka City. The fresh water deposits which is equivalent to P4 Zone between Ma11(3) bed and Ma12 bed under the bottom of Osaka Bay is correlative with the lower member of Uema chi Formation, because of the remarkable dominance of subarctic forest pollens and the correlation a characteristic volcanic ash layer between V2 layer in K021 site and a volcanic ash layer (FURUTANI, M., 1978) as newly naming Morinomiya volcanic ash layer in On6 site. Ma12 bed under the bottom of Osaka Bay which is characterized by the appearance of Cyclobalanopsis and Lagerstroemia is correlative with the middle marine clay member of Uemachi Formation, and both the marine beds were deposited in the same period by 114 Masakazu FURUTANI Uemachi Transgression estimated at ca. 130,000 y.BP. The upper member of emachi Formation which is characterized by the dominance of cool temperate forest pollens including Sciadopitys as shown in Fig. 13. The pollen assemblage is correspondingly found in the brackish or fresh water deposits above Ma12 bed under the bottom of Osaka Bay. The radiocarbon dates in the fresh water deposits being equivalent to b Subzone in P2 Zone are SS,700±3,300 y.BP and SO,600±2,400 y.BP. These deposits are unconformably covered by the Low terrace deposits which are determined radiocarbon dates younger than 2S,730±630 y.BP. The paleoclimatic change in an interval ranged from Mall(l) bed to the Nanba Formation is shown basing on pollen assemblage in Fig. 14 and it is revealed that the climatic transition through the Middle terrace period changed from subarctic (c Subzone in P4 Zone) to warm temperate (d Subzone in P3 Zone) and cool temperate (a and b Subzone in P2 Zone). 1--4. Low terrace deposits The Tonda Formation (Low terrace deposits) which is typically distributed in Settsu Tonda upland in Takatski City interbeds a coaly clay including cool temperate forest remains and Heianjingu volcanic ash layer (YOSHIKAWA, S. et al., 1986). And a radiocarbon date of this coaly clay was determined as 26,OOO±800 y.BP (ITIHARA, M. and KICOSHI, K.,1962). On the other hand, Itami clay bed and Itami gravel bed had been correlated with the Low terrace deposits (HUZITA, K. and MAEDA, Y., 1971), but it was revealed that they should be correlated with the Middle terrace deposits by means of pollen stratig raphy (FURUTANI, M., 1978). The deposits which are correlative with the Low terrace deposits are thickly and widely developed under the bottom of Osaka Bay in offshore area of Kobe Port as shown in Fig. 1S. Radiocarbon dates of these deposits are determined as 2S,730±630 y.BP ~ 2S,090±8S0 y.BP in their lower member, and 24,060±1,400 y.BP ~ 14,OSO±280 y.BP in their upper member. The pollen assemblages which include Sciadopitys and Cryptomeria in the lower member being equivalent to c~ e Subzone in P2 Zone show the cool temperate climate, and which include Picea, ef. Larix and Geranium and so on in the upper member being equivalent to f ~ i Subzone show the subarctic one. On the basis of these pollen as sembalge, paleoclimatic change is shown in Fig. 14. The Lower member interstratifies a marine deposit which is equivalent to c Sub zone, and this marine bed shows the sea level rising before or after 26,000 y.BP. The correspondence of plant fos il composition and radiocarbon dates of Tonda gravels with those of the marine bed lead to a conclusion that the Low terrace deposits in inland areas are mostly resulted from this rising of sea level. The cool temperate forest elements e.g., Fagus, Cryptomeria and Sciadopitys, are not found, but only Betula and Myrica (M. gale type) appear in g and i Subzone in P2 Zone. Temporary appearance of the cool temperate forest elements in the upper part Stratigraphical Subdivision and Pollen Zonation 115 (\J ~ V n.. n.. n.. c Q) 'U (J ',J i9 · i- · S ~ . · ',J ',J · i 0' · n U ',J · · · · · ',J · -'<'" ./ · S · · 0'" (y .... (y · 0 ? ~... & . '0 '"0- ./ ~ i- · ... E ~S ~ re ~ '-' LI-L-L-L-L-LI-LI-LI-l.'_LI---lI---lI---lI---l---l-----L1 116 Masakazu FURUTANI PoHen Assemblage Estimated Paleoclimate -10 o ~o 10('''1. Low~ --... High < : ' -20 ••••J "8 I··· ... .;: worm I OJ i 0- temp.G. ~)cool ro -30 .;; :: O{".,.~ I _••-.-_. ! c ()- : -90 { : I I I _-- c -c---:-:-~-r ... -100 ~arCriCG b -110 b a ;". ,-,I); -120 II c -130 b :j -140 -150 .R.!.----- Fig. 14. Total diagram of pollen assemblage and estimated paleoclimatic change in site Ko21 in offshore of Kobe Port. TP m KolO Kol2 Kol3 Ko20 Ko21 POLLEN ASSEMBLAGE GEOLOGY f-" ~ IST_IC_TAXA_t-_~_A_P_P_E_A_RrA-,N_C-,-E_-.-.--l7rFACIES ISOTOPE DATING estimated i I-OO_"_IN_A_N_T_T_A_X_A-!-_oww:te\ __-t- t-"""''----iAGE Cyelobolonopsis Cyelol>olonopsis y.BP Dip/oxylon Quercus Costonopsis Celtis 6500 ~" Gryptomerio Podoeorpus y.BP ~~ i Hoploxyfon aetula Quorcus Betula Larix Songul.crbo 14.0~0 ±280 lNUTA-246) 15000 h Hoplolfylon TsuOQ Pietto Cryptom."o Fogus Myrica '-19,J?bO£2Ifre0'r~:~iA 22500 HOp'OKY'on Abi.s Tsugo Abie, LOrioi' Menyanfftu Quercus ArtsmlSIQ CarpinUS Myrica 24,190 ±790 (NUTA- 248) 25000 Hop/oxy/on Tsugo Seiodopitys Fogus 2~,170 ±6~0 (NUTA-249) 24,060 14000-13951> .. t Sciodopitys Quercus Betula [ GYPERCEAE Artemisia Songuisorbo e Seiodopitys Alnus Seiodopitys o 2~,37 0 ±680 lNUTA-2~0) Cryptomerio Pieeo Pieeo Hoploxylon 2~,09O±J8~C1-1~ --50 Tsugo Hoploxylon Geronium ,~ 25500 Seiodopitys Alnus Betula Jugions o 2~.730±630(NUTA_ 2~ I) .Q i c Gryptomerio Cyclobo/onopsis CYPERACEAE logerstroemio I --63 o en 50000 b Seiodopitys Alnus Seiodopitys I: ~ 5~.700±3300 (NUTA-2~2) Sciodopitys A/nus Pieeo ~ 40,.500:t3600 a Gryptomerio Pleeo EUPHORBIACEAE (NUTA-2~3) f--70 Dip/oxy/on LoC}ersrroem;a Dip/oxylon Abies Tsugo Gyelobolonopsis _ humus Sciodopitys Fagus Ulmus Podoeorpus VOlcanic gloss Cye/obo/onopsis EUPHORBIACEAE ~ marine sediments logerstroemio Fig. 15. Lithologic succession and change of pollen assemblage with absolute dates ranged from Ma12 bed to the Nanba Formation in offshore of Kobe Port. AGE STRATIGRAPHY SUBMARINE SUCCESSION Climatic 6 Sea level Kinki District South Kanto D. Europe . change Plant Fossil Pollen (NeiMrlonds ) .c: telp'erature 'u sea leve I Kokawa,t961, Nasu, Tai, Onishi, Nishimura, Machida S. Suzuki 0 ~ Hammen, T.et aL,I971 {i Tuff,Glass Aile N III low high low high 972 Itw,arQ·et 01. 198E 1973 1977 1980 1971'1975 ., ~ :~ 04C,eI' ! d 10·y c: - i e -05U i c 0 Nanba Yoko-oji Fl. 0 Middle U PI- i K8 0 t/~ -05MGI ~ b I F. _O!W.. ~ --0 i I--- r--- Lower I.,ceo - -G2 i L.M.Oomihachimoo FI. LateQlacial 0 c -1>3 ••010 0 I -g -G4 I P d ~ 0. Tondo F. - I-- P2~ " i Pleni-olacial I ) . Tonda FI. E ~ -05 T ------• 6.6±0.6 .! Upper ~ ""lOO ~ 'jl Early CJlacial :~ ~ 0 ~± Shimosueyoshi L. -I Uemochi • 9.8±1.2 Mal2 ~ d Shimosueyoshi F. ·12.8±1.I Eemian Middle P3c I F. bed I ~ Hirakata FI. Ulmus - Ze/kova Riss Wurm Intergladel ~ - .3 -~ ~r '--~~ - ...L D Tsuchihashi L Sao lion 'I I Pieea - ~± ~ P5 ~ 1 ~ ~ - ~ i (L III - i---I- i ".., - - c \·l ~ Sannodai L. l- 1\, ~ MolO ~ " .- ! PII b i :) Diplaxylon ~ bed ~ i) 210,000 ~ t; ~.) - Cryptomeria - i---I------·r Kitashinoda c. T a. c: i---I- k ------::J - d N I- Kamikurata F. ~ l- l\ i \ e ~ " Syzygium Fl. (9 M09 I' >. PI3 b ~ ~ ) (at UegoharaJ v Fagus 0 bed ~ - I c: H ..x: 0 1/ 0 - Cyclobalanopsis 0 ~ :x: ~- .J,''''' N II) - 0 II) i---- ~ ·t ::J f-- -~ ....:... 01 Byoou\laura Ii.. 0 F. MoB ~ PI5 b , 1\ IJ... ~ - I! G Haploxy/on bed 0 it' -Fagus -~ ~- ( f Fig. 16 Stratigraphic correlation between Kinki and South Kanto Districts since Middle Pleistocene to Holocene. Stratigraphical Subdivision and Pollen Zonation 119 of h Subzone is inferred to be a climatic improvement, because the base of the Alluvial formation (Namba Formation) is estimated at about 22,500 y.BP in age. 2. Correlation between Kinki and South Kanto District Since the Middle Pleistocene, in Kinki District, the strata under the bottom of Osaka Bay which are interstratified with ten marine or brackish beds ranged from Ma8 bed to the Namba Formation, have been accumulated. The strata consist of five stratigraphic units and are divided into four pollen zones, twelve pollen assmeblage zones and fourty one subzones. The paleoclimatic change and the sea level change in submarine succe ssion of Osaka Bay are summarized in Fig. 16. ONISHI, I. (1977) divided the Pliocene and Pleistocene strata into seven pollen zones in central and southwest Japan, and correlated the strata ranged from Ma6 bed to Terrace deposits in Kinki District with the uppermost part of the Kazusa Group and the Sagami Group in Kanto District by Cryptomeria Zone (K7 Z.). NISHIMURA, S. (1980) subdivided the Middle and Upper Pleistocene ranged from the Naganuma Formation to the Musashino Loam Formation into nine pollen assemblage zones in South Kanto District. As shown in Fig. 16, the change of pollen assemblage from the Byobugaura Formation to the Shimosueyoshi Formation is meaningfully corresponded with one in Kinki District. Haploxylon Zone is correlative with Haploxylon-Fagus Zone, Fagus-Cyclobalanopsis Zone and Diploxylon-Cryptomeria Zone, and particularly the Kami kurata Formation is characterized by the dominance of Cyclobalanopsis such as Ma9 bed. Cf. Pseudotsuga Zone is correlative with Diploxylon-Fagus-Ulmus Zone appearing d. Pseudotsuga in the Maioka Formation which is determined as 285,000±28,OOO y.BP by fissiontrack dating. P4 Zone is correlative with Picea Zone in the Tsuchihashi Loam Formation. Lagerstroemia Zone is correlative with Ulmus-Zelkova Zone appearing Lager stroemia in the Shimosueyoshi Formation which was determined as 128,000±11,000 y. BP by fission-track dating. Acknowledgements The author wishes to thank Prof. emeritus M. ITIHARA of Osaka City University for his valuable advice and critical reading of the manuscript. The author is also much indebted to Dr. S. YOSHIKAWA of Department of Geosciences, Osaka City University for his advice and help with tephrostratigraphical study, Prof. N. NAKAI and Dr. T. NAKAMURA of Nagoya University for their helps with radiocarbon determination, Dr. K. NAKASEKO and Prof. emeritus K. TANIMOTO of Kobe University for their helps with the study in offshore areas. References FURUTANI, M. (1978): Upper Pleistocene Series of the western Osaka Plain (in Japanese with Eng lish abstract). JOllr. Geol. Soc. Japan, 84, (7), p. 341-358. 120 Masakazu FURUTANI FURUTANI, M. (1979): Studies on the forest history in the Osaka Area scince Wurm Glacial Age in Japan (in Japanese with English abstract). Daiyonki Kenkyu (Quaternary Research), 18, (3), p. 121-141. FURUTANI, M. (1984): Pollen Stratigraphy of the Submarine Strata at the Kansai International Airport in Osaka Bay (in Japanese). p. 91-116. in Geological Survey of the Submarine Strata at the Kansai International Airport in Osaka Bay, Central Japan. edited by NAKASEKO, K. 285 ps. FURuTA I, M., SATO, K. and OTAKE, Y. (1983): The Upper Pleistocene in coastal area of Kobe City (abstract). 90th Ann. Meet. Geol. Soc. Japan, p. 86. HAMMEN, T. van der et a!. (1971): The Floral Record of the Cenozoic of Europe. Late Cenozoic Glacial Age (edited by TUREKIAN, 1<.1<.), Yale Univ. Press, p. 425-464. HUZITA, K. and MAEDA, Y. (1971): Itami Terrace with special reference to the Late Pleistocene transgression in Japan. Jour. Geosci. Osaha City Univ., 14, p. 53-70. HUZITA, K. and MAEDA, Y. (1984): Geology of the Suma district (in Japanese with English ab stract). Quadrangle Series, scale 1 :50,000, Geo!. Surv. Japan, 101ps. IKEBE, N., IWATSU, J. and TAKENAKA, J. (1970): Quaternary Geology of Osaka with Special ref erence to land subsidence. Jour. Geosci. Osaha City Univ., 13, p. 39-98. ITlHARA, M. (1960): Some problems of Quaternary sedimentaries in the Osaka and Akashi Areas, Japan (in Japanese with English abstract). Chikyu Kagahu (Earth Science), (49), p. 15-25. ITlHARA, M. and KIGOSHI, K. (1962): Radiocarbon dates of peat and fossil-woods from the recent and terrace deposits in the neighborhood of Osaka (in Japanese). Chikyu Kagahu (Earth Science), (58), p. 35-36. ITIHARA, M., YOKOYAMA, T. and ISHIDA, S. (1966): On the Manchidani Formation (in Japanese with English abstract). Daiyonki Kenkyu (Quaternary Research), 5, (2), p. 65-72. ITIHARA, M., S. YOSHIKAWA, K. INOUE, T. HAYASHI, M. TATEISHI and K. NAKAJIMA (1975): Stra tigraphy of the Plio-Pleistocene Osaka Group in Sennan-Senpoku area, South of Osaka, Japan. JOllr. Geosci. Osaka City Univ., 19, p. 1-29. hlHARA, M., ICHIKAWA, K. and YAMADA, N. (1986): Geology of the Kishiwada district (in Japanese with English abstract). With Geological Sheet Map at 1 :50,000, Geo!. Surv. Japan, 148 ps. KOKAWA, S. (1961): Distribution and phytostratigraphy of Mellyanthes remains in Japan. Jour. BioI. Osaka City Univ., 12, p. 123-151. Komyoike Research Group (1971): The Osaka Group around Komyoike in the Shinodayama hills, south of Osaka (in Japanese with English abstract). Chikyu Kagaku (Earth Science), 25, (5), p. 201-210. MIKI, S., HUZITA, K. and KOKAWA, S. (1957): On the occurrence of many broad-leafed ever-green remains in the Pleistocene bed of Uegahara, Nishinomiya City, Japan. Proc. Japan Acad., 33, (1), p. 41-46. MINAKI, M. (1983): Morphology of Pinus armandii aff. var. amamianG from the Middle Pleistocene of Japan. Acta Phytotax. Geobot. 34, (4-6), p. 148-157. MULLER, J. (1959): Palynology of recent Orinoco delta and shelf sediments: Reporrs of Orinoco shelf Expedition 5. Micropaleontology,S, (I), p. 1-32. 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