The Prototype of JinhuaQuzhou Basin and Its Gas and Oil Foreground

Key words: 
• JinhuaQuzhou Basin /
• prototype analysis /
• center of subsidence /
• tectonic environment /
• oil and gas

Abstract: South China is one of the most complex area with continental reconstruction. Under the evolution background of tectonic regime and heat system, different basin types had been shaped with the distinguishing feature of identical phase prototype basins coming to being combined and distinct phase archetype basins being superposed. Generally, South China has two stage prototypes of marine facies original mold from Palaeozoic Era to Early Indosinian and Mesocenzoic terrestrial facies antetype; the former being labeled by fluctuating sea level, being accompanied by ingression and regression of the sea, being presented by relatively integral cyclic depositional series, and shaping the marine facies prototype basin, and the latter undergoing relatively frequent tectonic events, having multiphase tectonic reworking on marine facies prototype basins and overlapping above last term prototype, creating varied conditions of bearing, storing, and capping. For JinhuaQuzhou basin is typical representation of Mesocenozoic land facies prototype basins, being situated in kernel place of South China, by studying its key elements of prototype and recognizing entirety through part, theoretical references can be provided for researching tectonic setting evolution history and filling history of Southeast China and even the whole South China, guiding denotation on the aspect of oil and gas exploration activity.
JinhuaQuzhou Basin is one of the late Mesozoic rifted basins in Southeast China. It developed on the Premesozoic metamorphosed fold basement, mainly including three structural units of northern shallow depression zone, central uplift belt and southern hollow zone. Making use of analytic approach of basin prototype, tectonic events, deep seated structure, provenance, subsiding history, depocenter, basin boundary structure and cessation of deposition, and so on, were studied. JQ basin had undergone several evolutionary phases of early intracontinental compressing, late early Crataceous extending and drafting, late Crataceous depression, suppression of last stage of Crataceous and reformation of later stage. From research above, basin filling material was coming from ablation due to incipient fold and uplift of PreMesozoic formation and weathering denudation of mountain mass with the background of late period drafting, 〖JP2〗confirming that JQ basin had experienced uplifting and denuding events attributing to the mechanism conversion from extruding to pulling. These events had important affection on the shaping of rifting and half grabenlike basin. Sedimentation and subsidence center was in the vicinity of Quzhou with more or less translational migration during the three palaeolithofacies stages. From the study above, we can see that JQ basin has favorable oil and gas foreground, and these four structural traps of Qianjia, Shuiting, Yangtang and Jiangtang have major prospecting potentiality.〖JP〗
It is the property of local area that JinhuaQuzhou basin has tectonic framework of "one uplift and two depressions " with the northeastern strike direction. Being combined with the territorial structural framework, JinhuaQuzhou basin was controlled by westeastern basement tectonics of ageold Asian domain and restrained by deep seated structure. Kinetics contributing factor of every structural zoning of the basin presenting northeastern distribution was intimately related with the tectonic regime of age old Pacific Ocean. Since the sedimentation of Cretaceous Period, basin building and evolving main part had been controlled by crossfeed relationship of late Mesozoic structure, magma, deep lying and the basin itself of Southeast China, being affected by PreMesozoic mountain building and tectonic regime of age old Pacific Ocean. JiangshanShaoxing faulted zone was the important geotectonic unit border that had been governing areal structure, inner basin building and depositional sources of JinhuaQuzhou basin.