Sedimentary basins in arc-trench system as a high-sensitive recorder of oceanic plate motion

Abstract

The change of oceanic plate motion might be recorded in the strata of arc-trench system, because the difference of thickness is remarkable between the oceanic plate and the sedimentary bodies in the basin as shown in Fig. 1.
Plate motion during the least 42 Ma: JACKSON et al. (1975) presented the periodicitic changes of loci of individual shield volcanoes along the Hawaiian chain (Fig. 3a). They concluded that the Pacific plate has been subjected to oscillatory, but principally clockwise, rotations of horizontal stress components as shown in Fig. 3c. In this paper, it is presumed that the oscillatory curve in Fig. 3c means the periodicities of real rotational motions of the Pacific plate. The changing point (maxmum or minimum in the curve) between two torque is called "JACKSON episode".
Plate motion during the least 175Ma: Relative motions during late Mesozoic and Cenozoic were calculated by ENGEBRETSON (1982) between oceanic and continental plates in the Pacific region based on the magnetic anomaly lineations, fracture zone trends and hotspots. MARUYAMA et al. (1982) presented the relative motion of the Pacific, Kula and Farallon plates with respect to Eurasia plate at the Japanese Islands (Fig. 13 (2)-(5)) using the ENGEBRETSON'S data.
On the basis of these history of the plate motion, the various phenomena, such as igneous activities, tecton-ism, sedimentation and sea level change, are correlated and discussed for the Cenozoic and Mesozoic in the basins of the Japanese Islands which have precise chronologic discrimination. The JACKSON episodes of the changing time of the Pacific plate motion may correspond to the events of igneous activity (Fig. 4 (1) (2)), the change of stress field (Fig. 4 (3)) and the intensity of tectonism, such as the period of unconformity, deformation or movement (Fig. 6 (3), 9). JACKSON episodes also control the rise and fall of sedimentary basin, that is, the variation of sedimentation (Fig. 5-8), depositional rate (Fig. 7-9), hiatus (Fig. 6-8), subsidence (Fig. 7) and paleobathymetry (Fig. 8). Moreover, the same relationships can be obtained between the plate motion and geologic events for the long history in the basin. Grobal cyclic curve of relative sea level change proposed by VAIL et al. (1977) (Fig. 10) records the changes of plate motion (Fig. 12, 13). The cyclic curves can also explain some phenomena of transgression and regression, but not the intensity of the phenomena in the basins of arc-trench system.
The agreements among these episodic periods or events suggest that oceanic plate motion is the most important factor for the various geological phenomena in the sedimentary basin of arc-trench system. The images of the process, mechanism or effect are also presented for these relationships based on the plate motion.