Northwestern Kyushu Research Articles

Tooth Size of the Protohistoric Kofun People in Southern Kyushu, Japan.

Metrical dental characteristics were investigated in the Kofun series in southern Kyushu. The results of t-tests and Penrose's size distances showed that tooth size in the Kofun series in southern Kyushu was larger than those of the Jomon series and the Yayoi series in northwestern Kyushu, except for the buccolingual diameters in males of the Yayoi series, which were almost equal in size, although smaller than that of the Yayoi series in northern Kyushu. As regards Penrose's shape distances, the Kofun series in southern Kyushu was close to the Yayoi series in northern Kyushu as well as the West-Kofun and East-Kofun series. On the basis of bone and dental morphology, the Yayoi people in northwestern Kyushu are considered descendants of the Jomon people. However, the Yayoi people in northern Kyushu are generally thought to have been influenced by immigrants. Matsumura (1990) noted that the dental characteristics of the West-Kofun and East-Kofun series were closely related to the Yayoi immigrant people in general. Over all, the dental characteristics of the Kofun series of southern Kyushu are closer to those of the immigrant population than those of the native population. Therefore, the Kofun people in southern Kyushu should be considered influenced by the immigrant population.

九州北部，北松浦玄武岩類のソレアイトとアルカリ玄武岩の成因関係

九州北部，北松浦玄武岩類のソレアイトとアルカリ玄武岩の成因関係

Genetic and Archaeological Studies on the Variation of Grain Dimensions of Carbonized Rice in the Ancient Remains of the Northern Kyushu Island of Japan.

Dimensions (length, breadth and thickness) of carbonized rice grains excavated from 12 archeological sites were measured to investigate the origin of ancient Japanese rice . The ages of rice grains excavated were from the late Jomon to the Yayoi eras (from c.500 B.C. to c.300 A.D.). The excavation sites were located in the northern part of Kyushu, Japan. The 13 different materials from 12 excavations were analyzed for variations of the grain dimensions and were compared with those of 16 modern rice cultivars. The twelve sites were located in three geographical regions: three sites in the north-western Kyushu sea-shore region facing the Sea of Genkai, seven sites in the Chikushi alluvial plain region, and one of other two sites in the northern inland and the north-eastern sea-shore facing the Sea of Suo. The oldest sites were located in the north-western Kyushu sea-shore region. About 100 grains randomly sampled from the large masses excavated were measured using scaled photographs. In the cases where fewer than 180 grains were excavated, all available grains were measured. Results are as follows: 1.) The lengths of grains from the three sites in the northwestern efyushu sea-shore region were all shorter than those from the other nine sites.

Species turnover and diversity patterns along an evergreen broad‐leaved forest coenocline

Direct gradient analysis was applied to the evergreen broad‐leaved forest coenocline in the Tatera Forest Reserve, Japan. 10 quadrats of 0.1 ‐0.05 ha were laid out from 140 m to 560 m above sea level at intervals of 25–70 m. Gradient analysis revealed that distributions of many species terminated or started at ca. 400 m. Community similarity, calculated in Percentage Similarity (PS) and Community Coefficient (CC), changed abruptly below and above the 400 m contour, suggesting a change of vegetation structure at this altitude, which was also clear from population distributions.The spatial turnover rate of species along the altitudinal gradient was calculated in two ways: as the Average turnover rate along the whole range of the gradient, and as the Zone turnover rate at individual altitudes. The overall rates calculated for five categories of populations: DBH > 10 cm, DBH >3 cm, all woody species, herb‐layer, and total vegetation, were‐ 0.0011 to‐ 0.0021 for PS, and ‐ 0.0009 to‐ 0.0019 for CC. The calculated rates (PS basis) indicate that a 95% change in species composition is reached at 1120 to 620 m altitude. Similarly, the rates ‐0.0009 to ‐ 0.0019 (CC) correspond to 1410 ‐ 680 m. The altitudinal range expected here for a 95% change agrees with the actual elevation of forest zonation in northwestern Kyushu. The average rate of both PS and CC in the herb‐layer population was 1.56 times higher than the rate in the woody species population, showing a more rapid change in herb‐layer population than in the woody ones along the gradient.The Zone turnover rates were higher at the 370–440 m belt than those below and above the belt. This coincided with the interchanging pattern in population distributions and the abrupt change in similarity at about 400 m above sea level. This may be due to the change in environmental conditions such as physiography and air humidity. In the diversity measurements, the species density per 100 m2 showed a gradual increase in the DBH >3 cm population but a constant level in the DBH >10 cm population along the whole range of the forest coenocline studied, while index values of S(100) and Shannon's H showed decreasing trends in the same gradient with a few exceptionally high and low values.

Chemical Composition of Precipitation and Wet and Dry Deposition of Sulfur Compounds around the Northwestern Kyushu Region

Chemical Composition of Precipitation and Wet and Dry Deposition of Sulfur Compounds around the Northwestern Kyushu Region

対馬海狭周辺のテクトニクスと今後の問題点

Characteristic distributions of shallow crustal earthquakes and active faults can indicate tectonic activity, because both are thought to arise chiefly from tectonic instability.Central Kyushu is the most seismically active region of the island. This active seismogenic region can also be defined as a NE-SW-trending active normal fault zone, which would lead to progressive spreading. On the other hand, northwestern Kyushu, including the Tsushima Strait, is postulated to have a low concentration of strain energy, and a comparatively stable condition is inferred in this region in terms of geomorphic indices and landforms. Thus, the Tsushima Strait region cannot be regarded as a potential tectonically active zone. However, the tectonics of the region are still not understood in detail. Sufficient information on Holocene marine terrace surfaces and on submarine tectonic structures in and around the Tsushima Strait remains to be obtained.

A53 北西部九州の火山岩類のフィッション・トラック年代

A53 北西部九州の火山岩類のフィッション・トラック年代

九州北西部，多良岳地域の火山地質

九州北西部，多良岳地域の火山地質

Confirmation of spawning groups of Japanese jack mackerel Trachurus japonicus in the low stock level period.

Spawning groups of Japanese jack mackerel Trachurus japonicus in the low stock level period were segregated. Segregation was done by the visual examination of monthly changes of the frequency distribution of fork length and/or partly the monthly changes of the mean gonad index. In the Kuroshio Current System, two spawning groups were recognized: the spring spawning group spawns in spring mainly from February to April and distributes from southern Kyushu to Kanto region; the summer spawning group spawns in summer mainly from June to August and is present only in Kanto region. In the East China Sea and Tsushima Current System, two spawning groups are recognized: the winter spawning group spawns in winter mainly December to January and is present in Wakasa Bay and Noto regions; the spring-summer spawning group spawns from spring to summer mainly April to June and is present in northwestern Kyushu region. Comparison of the population structure of both high stock level (former studies) and low level (present study) shows that basically no differences between the two periods exist.

K-Ar ages of basalts from the Higashi-Matsuura district, northwestern Kyushu, Japan and regional geochronology of the Cenozoic alkaline volcanic rocks in eastern Asia.

Seven new K-Ar age determinations are presented on whole rock samples from alkaline and tholeiitic basalts of the Higashi-Matsuura district, northwestern Kyushu, Japan. Ages obtained range from 2.92 ± 0.03Ma to 3.01 ± 0.04Ma; these ages are essentially identical within analytical errors and yield an average age of 2.98 ± 0.03Ma (Late Pliocene). When combined on an isochron type diagram the six Higashi-Matsuura samples give an age of 3.00 ± 0.03 Ma with the composition of nonradiogenic 40Ar/36Ar = 294.2 ± 2.0. The excellent age agreement of samples with different K contents and petrographic characteristics provides strong evidence that the tholeiitic and alkaline basalts were erupted for an extremely short period in the Higashi-Matsuura district. A basalt from Ogawashima Island yields a K-Ar age of 3.58 ± 0.04Ma. This study and previously reported data support the hypothesis that alkaline volcanic activity in southwestern Japan commenced some 10Ma ago and continued intermittently until Recent times. Systematic variations of age and distribution of Cenozoic alkaline basalts are recognized in northeastern China, Korea and southwestern Japan. It is suggested that these variations are related to the initiation of “mantle plumes” resulting from convection in the mantle wedge caused or controlled by subduction of the Kula and Pacific plates.

長崎豪雨(1982年7月23日)の解析

A case study is made of an exceptionally heavy rainstorm that hit the northwestern coastal area of Kyushu, Japan, on 23 July 1982. The 5hr rainfall accumulation was as high as 412mm at the city of Nagasaki. The precipitation occurred along the warm front as-sociated with a medium scale disturbance that developed along the Baiu front. The atmos- phere in the pre-storm period was very moist through virtually the entire troposphere and its static stability was conditionally unstable with a lifted index of -1.5°C, thus exhibiting characteristics more similar to the tropical atmosphere than the typical pre-storm environment over the midwestern United States in spring seasons.Prior to the development of heavy precipitation over the Nagasaki area, an intensive rainband was propagating with a speed of 40km hr-1 eastsoutheastward over northwestern Kyushu. Its structure is found to be different from the structure of typical tropical squall clusters in that the heaviest rainfalll occurred in the middle of the rainband without a well defined leading edge. A dramatic change occurred in the rainband when its southern tip reached the Nagasaki area; it stopped propagating and stayed there for the next 5hr. Its line structure changed to a blob structure at the meso-β scale (-100km). The timing of the precipitation development at Nagasaki coincided with the peak period of the incursion of very moist air associated with the southwesterly low-level jet. During the period of heavy precipitation, a new cloud cluster formed over the sea 300km west of Nagasaki. It kept developing and propagating eastward with a speed of 60km hr-1, and eventually merged with the rainstorm over Nagasaki. These observations strongly suggest that the Nagasaki rainstorm was trapped orographically. Several other heavy precipitation events are cited which also occurred in association with medium scale disturbances along the Baiu front and in which the precipitation developed over the coast areas upwind of the low-level jets.

Non-Hodgkin's lymphoma in northwestern Kyushu Island of Japan. Clinicopathological studies based on the Japanese classification of malignant lymphoma.

Ninety cases of node-based non-Hodgkin's lymphoma in northwestern Kyushu, Japan were classified according to the Japanese Lymphoma Study Group (LSG) and the immunological as well as clinicopathological studies were performed. There were 6 cases of small cell type, 23 of medium-sized cell type, 25 of large cell type, 20 of pleomorphic type, 10 of lymphoblastic type and 6 cases of specific lymphomatous lesions (Lennert's lymphoma and T-cell lymphoma with angioimmunoblastic lymphadenopathy-like pattern). Immunologically, the T-cell character was predominant in pleomorphic type (100%), specific lymphomatous lesions (100%), medium-sized cell type (80%) and large cell type (60%). Clinically, leukemic manifestation was frequently encountered in all histological types except for large cell type. The leukemic cells in pleomorphic type and T-medium-sized cell type were polymorphic, similar to those of adult T-cell leukemia. Skin lesions were found chiefly in leukemic cases of pleomorphic and T-medium-sized cell types, and non-leukemic cases of T-large cell type. The worst prognosis was observed in the pleomorphic type, especially of leukemic form. These results support the proposal of pleomorphic type as a distinct entity in prospecting the immunological subtype, clinical manifestations, and survival. In addition, T-medium-sized cell and pleomorphic types, having common clinicopathological characteristics, may be categorized as one group. On the other hand, T-large cell type seems to be composed of heterogenous groups of the peripheral T-cell tumor, although some cases overlap with pleomorphic type.

Eolian origin of quartz and mica in solls developed on basalts in Northwestern Kyushu and San-In, Japan

Abstract Quartz and mica contents were determined as a function of particle size of soils over quartz and mica-free basalts in northwestern Kyushu and San-in. The contents of both minerals were much higher in the surface soil horizons than in the lower horizons. Quartz particle size distribution (predominantly 2 to 53 μm) and surface morphology (chip or shard, not euhedral) which are similar to those in the north central Pacific pelagic sediments and Hawaiian soils, indicated that quartz is added as aerosolic dust and loess carried by the circumpolar Westerly Winds from Asian semi-arid and arid regions. Close proximity to the eolian sources was deduced by somewhat coarser texture of the present soil quartz. Lower surface soil quartz content, relative to that in the Hawaiian soils was interpreted as indicating a younger landscape age caused by intensive denudation. The covariant relation between the quartz and miea eontents of soils may suggest that at least a portion of the micaceous minerals and quartz i...

Geomorphology and tectonic movement of the sea floor, northwest off Kyushu, Japan

As a result of the sea bottom survey of continental shelf northwest off Kyushu including Tsushima, Iki and Goto Islands which has been carried out by the Hydrographic Department of Japan, the following features of the area are revealed. Topographically, three groups of shelf channels, trending NE-SW, N-S and NW-SE respectively, are discovered and several small banks are found. Sand wave-like shapes are also seen in a seafloor about 200 m deep in the vicinity of Tsushima Straits. Geologically, remarkable tectonic lines characterized by faults and folding axes are confirmed and named Tsushima, Iki, Hirato and Goto Tectonic Lines. Several tectonic provinces can be defined by these tectonic lines. Each province consists of small geological blocks formed by indivisual tectonic movement such as tilting, uplifting and sinking. Such differential tectonic movement is often seen on the continental shelves around active island arc. In this area, these tectonics might be caused by activity of the Ryukyu Arc. This area may thus be a metastable portion existing between the northwestern Kyushu and the Asiatic continental block. The present submarine topography is probably closely related to these tectonics in addition to the eustatic sea-level changes in Quaternary age.

Studies on Micromorphological Properties of Red Soils and Paddy Soils in Northwestern Kyushu.

Studies on Micromorphological Properties of Red Soils and Paddy Soils in Northwestern Kyushu.

四国古第三系および白亜系の高圧物性について

In order to start a comparative study of Japanese Palaeogene and Cretaceous sedimentasy basins, the dry sandstone samples from Muroto Peninsula, Izumi, and Kuma groups in Shikoku were studied with high pressure experimentation up to 1500 bars. All studied rocks are coarse or medium grained well sorted sandstones and collected from 6 localities which are different each other in geological horizons. Porosity ranges between 2.2 and 5.7%. The stressstrain curves as the result of the experimentation are shown in Figs 2 to 7. In these figures, strong dependance of porosity for both strength and deformational behavior was obviously indicated. The relation of strength versus porosity is shown nearly linear in semi-log diagram at each confining pressure as indicated in Fig. 9, although the sampling localities are scattered in three different sedimentary basins.Comparision with Kishima-Sassebo groups in northwestern Kyushu was shown in Fig. 8.In this Kishima-Sasebo basins, thick sedimenttary cover of approximately 3500m have been deposited, and, it is indicated, that as it is getting deep, porosity and deformational behavior changes regularly from the brittle deformation of less porous samples seated at lower stratigraphic horizon (HSF or HSG) to the more ductile deformation of more porous samples at upper horizon (HSD or HSC). Such a good accordance with Kishima-Sasebo groups in porosity-deformation relation indicates that the strength-porosity relation in Shikoku sandstones is closely related with compaction mechanism.

Holocene Shell Bed in Imari City, Saga Prefecture, Kyûshû, Japan

The Holocene marine deposits, here called the Imari Shell Bed, was exposed by digging for construction of a water reservoir near the head of Imari Bay, northwestern Kyushu. The marine deposits measure 3.4 meters in thickness and its upper surface is 0.4 meters above the sea level. The deposits consist mainly of silty sediments in which abundant marine molluscan shells and poorly carbonized plant fragments are contained.The molluscan fauna comprised of 22 species (Table 3), including eight of gastropods, one of scaphopods and 13 of pelecypods. All of these species are dwellers of an embayment environment and are known to range from the high tide down to the shallow neritic zone. Among the distinguished species, Anadara granosa bisenensis has been accepted as an index subspecies marking the Holocene transgression phase in Japan. Although no diatom fossils were discovered in the shell bed, pollen and spore fossils could be extracted from the silty sediments, and these are listed in Table 5. The fossil floras points to a warm climate during deposition of the Imari Shell Bed.The radiocarbon dating on the carbonized wood piece occurred from the upper part of the Imari Shell Bed indicates an age of 4430±85 yrs. B.P. (GaK-4486).A relict sea cliff characterized by such erosive features as, notch, pit, cave, crevice and overhang is well preserved along the inner margin of the alluvial plain of the Imari Bay area, and occur up to about four meters above sea level. Honeycomb structures were also recognized in the cliff.From the paleontological and topographical evidences, it is considered that the Imari Shell Bed was deposited during the rising of sea-level up to less than four meters above the present sea level. This marine transgression probably corresponds to the middle stage of the Jomon Period.

On the Human Skeletons of Yoyoi Period Excavated at the Sites in North-Western Kyushu

In the course of several excavations carried out from 1964 to 1969, some 100 skeletal remains were obtained from the burial sites in north-western Kyushu. These can be dated definitely to middle and early Yayoi period of prehistoric Japan.Among the skeletal remains collected, the skulls (_??_: 21, _??_:15) and right femurs (_??_:16, _??_:8) were examined anthropologically by the present author.The main characteristics of these skeletons can be summarized as follows.1) The skulls of the Yayoi ancients of north-western Kyushu are mesocephalic, orthocephalic and metriocephalic in both sexes. In respect of the averages main calvarial mesurement and indicies, in both sexes, there are no significant difference among the Yayoi people of north-western Kyushu, Mitsu and Doigahama and Jomon people of Tsukumo.2) The Yayoi people of north-western Kyushu are in both sexes lower in facial and upper facial height than the Mitsu and Doigahama Yayoi people. The mean values of the bizygo-matic and middle facial breadth of both sexes are shown to that in Mitsu and Doigahama. Therefore, the averages facial and upper facial index in north-western Kyushu are shown, in both sexes, to be smaller than that in Mitsu and Doigahama.Concerning all facial measurements and indicies, the Yayoi people of north-western Kyushu are, in both sexes, relatively similar to Jomon people of Tsukumo.3) The maximum length of the right femurs, as determined by Pearson's method, suggests that the Yayoi ancients of north-western Kyushu must have averaged 158.79 cm high for males and 147.91 cm high for females.Concerning estimated stature, the Yayoi people of north-western Kyushu, in both sexes, similar to Tsukumo Jomon people but is shorter tha Yayoi people of Mitsu and Doigahama. 9) The Yayoi skeletons from the sites of north-western Kyushu are characterized by a low face and short stature, namely, they show appearances of Jomon type rather than Yayoi (northern Kyushu) type.

Studies of the flood damages caused by heavy rainfall

The agriculture in Japan, especially in western Japan, suffers from flood damages.In this paper the author investigated the property of the heavy rains during the period from 7th to 10th of July 1967, recording the total amount of precipitation over 300mm in the north-western Kyushu, including the region of Nagasaki and Saga prefectures. Many severe flood damage landslides and their related damages occurred owing to the rainfalls.The results of the investigation from the standpoint of the local scales are as follows:(1) The heavy rains are composed of concentrated heavy rain caused by mesoscale disturbances passing along the Baiu front and of that associated with a low pressure.(2) The rain area is composed of 3 zones which stretched out from western Nagasaki to the Seburi mountains. The scale of rain cells (area) is about 10 to 20km in diameter and their intensity are at most 20-40mm per 10min.(3) In the later part of this paper, the author makes a survey of landslids, and occurrence of landslide related to the rainfall. The author suggests that the landslides are more closely related to heary rainfalls of 20mm/10min than hourly and daily rainfall.

Petrology of Tara-dake volcano, north western Kyushu.

Tara-dake volcano is located in Omura Peninsula, Northwestern Kyushu. This volcano forms the western end of Daisen Volcanic Zone. The basement of this volcano is consisted of early Tertiary sediments and Pliocene volcanics. The volcanic activity of Tara-dake can be devided into four stages. In the first stage, this volcano extruded alkali basalt flows principally with a little of calc-alkali andesite flows. The second stage is represented by numerous andesitic pyroclastic rocks, which directly cover the extrusives of the first stage. Most of the pyroclastic rocks are fit for the pyroclastic flow of the intermediate type (Armakai, 1957). They were formed by several eruptions of many volcanoes, constructing Tara-dake volcano. After this stage, andesitic lava flows were erupted and lava domes were formed finally. In reference to the genesis of calc-alkali rocks, it is the important fact that the alkali basalts and clac-alkali andesites were erupted successively. The successive eruption of calc-alkali rocks and tholeiite (or high-alumina basalt) is known in various volcanoes of Japan. But similar relation between alkali and calc-alkali rocks has not been found out up to this time. In this area, both series of rocks include many xenoliths and xenocrysts, and both were comparatively affected the contaimination effect. So the Tara-dake andesite might be derived from the alkali basalt which assimilated the crustal material.