A paleomagnetic study of some tertiary and quaternary rocks of Yamaguchi Prefecture, Japan

It is nearly four years since the results tabulated in Part VlI of this series were compiled. Parts I to V1I list the results up to the end of 1963, and these have all also been included in the tables produced by Irving in his book (Paleomagnetisnz and its Application to Geological and Geophysical Problems, Wiley, 1964). Because of the long interval since the last compilation, this one is rather larger than any of the previous ones and in it I have attempted to present all the results published since then up to the end of 1966. 1 do not claim that it is complete, but I hope in the first few months of 1968 to produce the next compilation (Part IX) which will include further results up to the end of 1967 and any which have been omitted from this one. Thereafter I plan that the compilations should appear annually summarizing the previous year's literature.I have made no attempt to alter the format devised by Irving for the previous lists, but T have given the references at the end in full, since I believe that this serves a useful purpose in making these summaries complete as far as is possible. The results are presented as a table with 20 columns. The information given in the originals is not always sufficient to allow entries in all columns. Columns 2, 3 and 4.Information about the rock units studied is given in columns 3 and 4. The symbols given in column 3 refer to the age of the rock unit: Quaternary Q, Tertiary T, Cretaceous K, Jurassic J, Triassic Tr, Permian P, Carboniferous C , Devonian D, Ordovician 0, Cambrian € and Pre-Cambrian Pc. Subdivisions of periods from Cambrian to Cretaceous, where recognized, are denoted by u, m or 1. Epochs within the Tertiary (Palaeocene, etc.) are denoted Tpa, Te, TO, Tm and Tp. Subdivision of the PreCambrian is not attempted.Columns 5, 6, 7 and 8. The appropriate stratigraphic thickness covered by the samples is given in column 5. In column 6 the spread of samples is indicated, either as an area, or as a distance between extreme localities in those cases where the localities are few or are distributed linearly rather than over an area. Pieces of rock or cores, separately oriented, are referred to as samples, and from them one or more specimens may have been cut. The numbers of samples and specimens are entered in columns 7 and 8.Columns 9, 10, 11 and 12. The stability tests carried out are noted in column 9.The tests noted here are these: fold test S, igneous contact test c, conglomerate test g , and alternating field a, steady field d and thermal t demagnetization. Results obtained from measurements of the natural remanent magnetization are denoted n 409 5 Identification numbers are entered in column 2.

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Palaeolatitude and Relative Position of South-West Japan and Korea in the Cretaceous

Yaskawa¹

1975

Geophys J Int

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All the palaeomagnetic results in south-west Japan were classified into three age groupings, namely, Cretaceous, Palaeogene-Miocene and Pliocene-Pleistocene, and an attempt was made to calculate the mean virtual pole position for each age group. From the pole position thus obtained the palaeolatitude at about the centre of south-west Japan was estimated for each age to be 41", 36" and 30" north.On the other hand, the mean virtual pole position for the Cretaceous was also calculated from palaeomagnetic results from Korea, and the palaeolatitude of Korea in the Cretaceous was estimated to be 37 degree north at about the centre of the Korean sampling sites. This value is almost 4 degrees less than the Cretaceous latitude at the centre of south-west Japan.Comparing the difference between the Cretaceous latitude and the present one at the centre of south-west Japan and that at the centre of Korean sampling sites, it can be concluded that south-west Japan has possibly drifted southward and, as the result of this drift, the Japan Sea has been expanded.

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A paleomagnetic study of some tertiary and quaternary rocks of Yamaguchi Prefecture, Japan

Cited by 5 publications

References 6 publications

Paleomagnetic synthesis for Southeast Asia: Constraints on plate motions

Paleomagnetic synthesis for Southeast Asia: Constraints on plate motions

Palaeomagnetic Directions and Pole Positions-VIII. Pole Numbers 8/1 to 8/186

Palaeolatitude and Relative Position of South-West Japan and Korea in the Cretaceous

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