On evaluating the paleodose in TL dating, there are two problems to be solved. The first is the supralinearity of TL response in the low dose range. The second is the sublinearity of TL response in the high dose (over 100 Gy) range.
We surmised that these phenomena are concerned with the electron-trapping process. A competition model was used for the supralinearity phenomenon, and an ordinary saturation model was used for the sublinearity phenomenon. We proposed a new equation combining these two models. Furthermore, using this equation, the coefficients were decided directly from the experimental data without regressive error. Also, the change in TL sensitivity after annealing could be represented by the change of only one coefficient.
This equation concerning these two phenomena offers well-fitting results with experiments from the low dose range to the high dose (2000 Gy) range. The annual dose rate is distributed in the range of 2.5 mGy/a. The age to which TL dating method is applicable, has been extended to about 10⁶ years by using the equation.
On three samples from the archeological sites in Miyagi Prefecture, by this method, the evaluated paleodoses range from 301.3 Gy to 626.5 Gy.

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Wavellite, variscite, planerite and cacoxenite were found in chert from Toyoda, Kochi City, as the first occurrence of aluminum phosphate assemblage in sedimentary rocks in Japan. They were formed on walls of fractures therein under a near surface condition. The phosphate ion came from nearby fluorapatite seam after the decomposition by sulphuric acid generated from pyrite in the intercalated slate after oxidation.
The chemical analyses of wavellite, variscite, planerite and cacoxenite indicate wavellite to be a high fluorine material, variscite to be a nearly ideal one, planerite to be a copper-bearing one, and cacoxenite to be a highly aluminian material, respectively. The X-ray powder studies on variscite and fluorapatite specify the former to be Messbach-type and the latter to be very close to end member. Under such a near surface condition, different geochemical behaviours of Al from Fell leads to the formation of aluminum phosphates without any essential Fe³⁺.

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K-Ar ages were determined on hornblende in 4 gabbroic rocks, one amphibolite, and one granodiorite porphyry from the Miyamori ultramafic complex of the Kitakami Mountains, Northeast Japan. The obtained K-Ar ages for gabbroic rocks range from 421 to 484 Ma. Most of them are Ordovician (445-484 Ma), excepting the age for one clinopyroxene hornblendite, which is middle Silurian (421 Ma). These K-Ar ages indicate that the Miyamori complex began to cool through the emplacement from the upper mantle to the shallower crustal level along the “Hayachine Tectonic Belt” in or before Ordovician. The amphibolite from a fenster in the complex gives a K-Ar age of 369 Ma. It contains considerable amount of secondary amphibole, which was probably formed by thermal effect of the Cretaceous Hitokabe granodiorite mass. Thus, the metamorphic age of the amphibolite is interpreted to be before middle Devonian. One hornblende gabbro from the “Hyachine Tectonic Belt” also gives an Ordovician age of 453 Ma. These fairly old K-Ar ages and arc-related petrological characteristics of the Miyamori complex suggest that the “Hayachine Tectonic Belt” dividing the North and South Kitakami Mountains was originated already in Ordovician as uplifted ophiolitic complexes formed at a consuming plate margin. The granodiorite porphyry gives a whole-rock K-Ar age of 112 Ma, suggesting that it is related to the early Cretaceous acidic volcanic rocks distributed to the south of the Miyamori complex.

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Hectorite-inorganic interlayer complexes were synthesized from a slurry having hectorite composition (Si:Mg:Li:Na=8:5.4:0.6:0.7) under hydrothermal conditions of temperature between 125° and 300°C, autogenous water vapour pressure and duration time of 2 h. These complexes were examined by X-ray powder diffractometry, and chemical, thermal, and specific surface area (SSA) analyses. On dehydration, low temperature synthesized complexes formed porous materials which were characterized by nanometer-size pores, large SSAs, and high thermal stability. The SSAs, which were measured on the samples heated at 300°C, decreased from 376 to 110 m²g^-1 with increasing the formation temperature, and were correlated well (r=0.99) to the amount of low temperature dehydroxylation calculated from the thermogravimetric loss between 300° and 650°C. X-ray diffraction patterns of the samples dehydrated in vacuum at room temperature or in air at 300°-500°C showed abnormally large spacing reflections (ca. 27 Å), that were accompanied with reflection peaks from collapsed layers. These results suggest that unreacted Si-Mg gel particles are intercalated between the hectorite silicate layers.

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Peipan-yama lava, distributed in a vast area in central Hokkaido, was dated by the K-Ar method. The obtained age is 3.4±0.2 Ma. Although many pyroclastic rocks distributed in central Hokkaido have been dated so far, their ages were either 5.7-3.7 Ma or 2.8-0.75 Ma and none of them was between 3.7-2.8 Ma.

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