On the Geology of Kang-tzu-tien District, a Suburb of Wafangtien, South Manchuria

Abstract

Wafangtien, the seat of the Fuhsien prefectural government, is located along the main line of the south Manchurian Railway, at a point some 10 km., north of the northern boundary of the Kuantung Leased Territory, and Kang-tzu-tien is a small village lying adjacently to the southwest of the town., The author investigated chiefly the Jurassic system developed in the Kang-tzu-tien district of some 1 sq., km., with special reference to the type of its structure, grade of disturbance and relation to other systems., The so-called Chiao-tou quartzite belonging to the Sinian system and developing in the western part of the district is paraunconformably overlain on its eastern side by the Lower and Middle Cambrian system which consists of quartzite or sandstone, slate and limestone., The Middle (?) Jurassic system under consideration which is composed of conglomerate, sandstone, sandy shale, coaly shale, and minor coal seams and measures some 200m., in thickness covers the eastern side of the Cambrian system clino-unconformably and is thrust by the Lower Proterozoic phyllites from the east with a thrust angle of 50°, Each one of these four systems is monoclinal to the east, and all of them except the Sinian system are covered by impure loess of the Quaternary or Diluvium., The general structure of the Jurassic system can be explained, in order of increasing accuracy, as (1) a monocline with easterly dip of about 50°, (2) a pitching synclinorium, (3) a pitching syncli., norium in the northern part plus pinching anticlinorium in the southern part or (4) a synclinorium-anticlinorium and cross-fold (or synclinal one)., For a more accurate description of the structure than is given by the fourth explanation, one must turn to such portions of the areas that have been investigated, and describe each of such portions separately., In the three areas where detailed investigation has been completed the structure is a combination of minor pitching anticlines and synclines with the axes of their folds generally pitching to the east., The axes of these minor folds are mostly separated for twenty or thirty meters from one another., The structure is not much disturbed by faults except the thrust mentioned above., It appears most proper to consider that the so-called Yenshan movement in the late Mesozoic period is responsible for the various contorted structures in different forms and scales which can be seen in the Jurassic system in the district.,