The detrital modes of sandstones in the Japanese convergent margin show distinct temporal variations since the Paleozoic. Lithic sandstones generally contain much more volcanic rock fragments than quartzose/feldspathic sandstones, and typically developed in response to episodic activation of arc volcanism which has been controlled by fluctuation in oceanic plate motions in the Japanese convergent margin. The temporal variations in the sandstone composition, mainly represented by fluctuation in the relative ratio of total lithic fragments, show a mode very similar to that in the sediment accumulation rate since the Triassic, and may be a sensitive record of sedimentary basin evolution in the Japanese convergent margin.
The general trend of temporal variations in the sandstone composition follows the one we can observe for the fluctuation in the rate of landward migration of coastal onlap curves of HAQ et al. (1987). Further the general mode of the temporal variations in the strontium isotope ratios and the preservation rate of sedimentary carbonate are also largely similar to that of the temporal variations in the sandstone composition in the Japanese convergent margin. The temporal variations in the sandstone composition in the Japanese convergent margin, therefore, appear to memorize flucutuations in sea levels and global chemical cycles through the Phanerozoic, which may also have been controlled by fluctuating plate motions.

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Some Middle-Late Jurassic radiolarian shells were detected associated with Early Cretaceous autochthonous radiolarian and anmmonite assemblages from the Lower Cretaceous formations of molluscan facies in eastern Shikoku.
The modes of occurrence on these Middle-Late Jurassic radiolarian shells were summarized as follows: 1) Specific diversity of associate Middle-Late Jurassic radiolarians are restricted within several species of Tricolocapa and Stichocapsa genera. 2) Most of these Jurassic radiolarians are subspherical with closed distal end in shape. 3) Their sizes are limitted to 100-150μm in length and 80-100μm in diameter. 4) Lithologically, they are contained in laminated sandy mudstones and sandy siltstones. 5) Among these older radiolarians, Tricolocapsa plicarum, T conexa, T. fusiformis?, Stichocapsa convexa and S. naradaniensis are the index species of Middle to early Late Jurassic age. But the other species whose final appearances are known within Earliest Cretaceous such as Cinguloturris carpatica, Pseudodictyomitra primitiva and Eucyrtidiellum pyramis have possibility that their ranges reach into Barremian age. 6) All these Jurassic elements are yielded from the first transgressive sediments successively just above the Lower Cretaceous nonmarine formations in the Northern and the Middle Chichibu Terranes. 7) These ammonites and radiolarians bearing Lower Cretaceous formations are the continental shelf or upper submarine terrace sediments, because they construct cyclothem together with the coal-bearing and blackish sediments which unconformably overlie both the melangé type Jurassic formations in the Northern Chichibu Terrane and the molluscan facies Middle-Late Jurassic formations in the Middle Chichibu Terrane.
The above-mentioned evidences showed that these Jurassic radiolarian shells are the reworked fossils in the same manner as other detrital clastics in the Cretaceous sediments, probably derived from the Pre-Cretaceous basement similar to the Northern and the Middle Chichibu Terranes. Therefore, it is necessary to consider the problem of reworking and mixing by older materials when we deal with the microfossil biostratigraphy at nearshore sediments on such continental shelf and/or upper submarine terrace.

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Siderite nodules formed in the oxygen-poor marine environments were obtained from the Middle and Upper Yezo Groups (Upper Cretaceous), Hokkaido, Japan. The siderite nodule is resulted from follwoing reaction:
Fe⁺⁺+2HCO₃^-=FeCO₃+CO₂+H₂O.
The observed siderite nodules occurred from dark gray, massive mudstone. The depositional environment of the mudstone is interpreted as quiet offshore facies. Compared with that of sediments deposited under higher oxygenated environments in the studies area, the dark gray mudstone is characterized by low diversity of benthic fauna, occurrence of siderite nodule and higher sulfur/carbon contents. The siderite nodules without pyrite suggest the sulfate-reduction by anaerobic bacterial decomposition of organic matter would not have been taken place. In addition to the paleoecological evidences, these facts also indicate post-oxic, nonsulfidic environments.
The nodules contain autochthonous low-oxygen tolerant inoceramids. For example, Inoceramus amakusensis is one of the low-oxygen tolerant inoceramids that would live on the soft muddy bottom with stagnant bottom water.
The fluctuation of post-oxic nonsulfidic and slightly sulfidic environments resulted in the two different mode of occurrences of inoceramids; concretion overgrowth around inoceramids during post-oxic nonsulfidic environments and concretion-free inoceramids in the mudstone during slightly sulfidic environment.

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A Tandetron accelerator mass spectrometer (AMS), based on mainly a tandem electrostatic accelerator and an apparatus to analyze charge state, energy, mass number, and atomic number of accelerated ions, has been used to measure ¹⁴C ages of geological and archeological samples, as well as ¹⁴C concentrations of natural samples, since 1983 at Nagoya University.
Traditional methods of radioactivity measurement have been applied to determine ¹⁴C ages of natural samples since 1947. However, their applications have been restricted to samples younger than 30000 to 40000y.B.P., as well as to ones from which 0.1 to 5 grams of carbon can be recovered. Usage of the Tandetron spectrometer has overcome these limitations. The amount of carbon necessary for the spectrometer is 0.2 to 5mg, being more than three orders of magnitude less than for traditional measurement. In addition, the oldest age measurable with the spectrometer has been extended to c.a. 60000y.B.P., as discussed in detail here.
The ¹⁴C background level of the spectrometer has been estimated by measuring ¹⁴C content of commercial graphite and mineral graphite from an ore deposit in Sri Lanka (Ceylon), which are too old to contain ¹⁴C. The background level corresponds to the apparent ¹⁴C age of 66340y.B.P. for commercial graphite and 64440y.B.P. for Ceylon graphite, as shown in Fig. 2. Amorphous carbon reduced by magnesium and graphite-like carbon deposited on iron-powder by hydrogen, from CO₂ prepared from “dead” carbon containing no ¹⁴C, show the apparent ¹⁴C ages of 37430 and 54000y.B.P., respectively. The solid carbon prepared from CO₂ gives a younger limit of the measurable oldest age than natural graphite, owing to the rather complicated preparation procedures which may introduce ¹⁴C contamination. Thus the method of producing amorphous carbon by reducing CO₂ with magnesium is not applicable to date such samples older than 40000y.B.P. The natural wood samples show ¹⁴C ages ranging from 59000 to 67860y.B.P., as shown in Fig. 3. These values are considered to indicate the oldest age measurable for woody materials.

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The study area, which is located in the Northern Fossa Magna region, is underlain by Miocene sedimentary rocks of the Aoki and Ogawa Formations. The Aoki Formation is composed mainly of mudstone and intercalates thin sandstone beds. The Ogawa Formation mainly consists of sandstone and conglomerate. The sediments of the both Formations are classified into eight seidmentary facies on the basis of the gram size and sedimentary structure. The sedimentary tacies of the Aoki Formation were formed under the slope environment. While those of the Ogawa Formation were nearshore origin. The sedimentary process of the Aoki and Ogawa Formations, are considered to have been controlled by the juxtaposed nearshore and slope, and by the sea level fluctuations in the coastal area.

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The paleo-wave conditions responsible for depositing foreshore sediments in Paleo-Tokyo Bay during the late Pleistocene were estimated. It was calculated from grain size and angle of parallel-laminae of the foreshore deposits and the thickness of step deposits of the Kioroshi Formation of Kozayama, Tamatsukuri-Cho, Namekata-Gun, Ibaraki Prefecture. The equations from flume experiments were used for calculation.
The Kioroshi Formation, the uppermost part of the Shimosa Group, distributes horizontally over the southern part of Ibaraki and northern part of Chiba Prefecture, and consists of a regressive sequence of coastal sediments deposited during the period following the Shimosueyoshi high stand of sea level. It includes parallel-laminated foreshore sands and trough cross-laminated pebbly sand filled the inner trough, which is called step deposits.
The result from the data of the lower part of the foreshore deposits, where is near the paleo mean sea level and the characteristic trace fossil is found abundantly, shows high frequency on the range from 1-2m in the deep-water wave height, and 10-14sec in the wave period. The estimated wave conditions are similar to the swell and winter waves in the recent Pacific coast and dominant (1%) waves at Kashima coast. This result suggests that the fairweather conditions were most likely to be preserved in the ancient foreshore deposits in this region.

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The Otsukayama Formation in the lower part of the Plio-Pleistocene Kazusa Group is isolately distributed in the western part of Boso Peninsula, Chiba Prefecture. The formation is consist of mudstone with slumping and sliding structures and was deposited on outer shelf or upper slope. The NNW direction of the slumping and sliding, paleo-slope directon, is estimated by sedimentary facies and fault analysis. Moreover, folds, sand dykes and diapir resulted from the slumping and sliding are also observed in the Formation.

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Onlap and downlap patterns, which are shown in the depositional model of sequence stratigraphy by H_AQ et al. (1987), were firstly found out in the exposed forearc basin-fill succession of the Plio-Pleistocene Kakegawa Group, Japan. The onlap-downlap patterns can be detected by the tracing of intercalated pyroclastic layers which have the same meaning as the synchronous reflection lines in seismic section. A depositional sequence recognized by the stacking patterns and unconformities in the Kakegawa Group might be produced by a global eustatic sea-level change from ca. 3.4Ma to 1.0Ma.

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The Izumiyatsu Mud is included in the lower part of the Jizodo Formation of the Pleistocene Shimosa Group. A lenticular fine-grained sand bed with climbing ripples is intercalated in the mud member. The sand bed can be divided into two units by a mud drape, and each bed shows opposit paleocurrents, ebb and flood directions. Moreover, time variation of the types of climbing ripple laminae within the sand bed also indicates a systematic variation of stream energy (velocity and/or sediment supply), which shows the same variation of that of tidal current. Thinly bedded alternation of sand and mud layers, about 70cm thick, overlies the climbing ripple sand bed. The thickness of the sand layers in the alternation changes cyclic pattern which can be explained by neap-spring tidal cycles.

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Grain-size analysis was held on the sediments (sand-size sediments in paticular) sampled in Paleo-Tokyo Bay area with a settling tube. The results indicate the importance of sedimentary processes in each environment. A shore-normal sorting trends and shifts is the skewness are interpreted as parameters controled by sedimentary mechanism: how carried, how deposited, and how much reworked. The mineralogical maturity and textural maturity are related correlatively.

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The Neogene sedimentary basins in the central Hokkaido were formed by the tensional stress field of the early Middle Miocene. This tensional stress field was related to opening of the Japan Sea. The Middle Miocene submarine fan was formed in the basin of the Hidaka coastal area. The submarine-fan environment changed into the fan-delta environment in the late Middle Miocene. The three stage progradations of the fan deltas were controlled by the sea-level fluctuations.

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The Middle Miocene Ogawa Formation in Northern Fossa Magna Region is composed mainly of sandstone and conglomerate deposited under nearshore condition. This Formation has ten cycles of sedimentary sequences in the study area. One sequence was formed by the transgression and following regression.
The conglomeratic sediments in these sequences are classfied into the six types. Three types of them were deposited in shoreface under storm condition. Two types of them were deposited in the upper-shoreface to foreshore. Another conglomerates was deposited on the transgressive surface.

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