科研之友
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摘要
Interpretations of subsurface data and computer simulations of basin-fill history in the late Neogene Pannonian Basin of eastern Hungary established a regional stratigraphic model presented in this paper. Three fluvial systems overfilled the basin: a large system from the NE, another from the NW and a third smaller system transported sediments from the territory of Romania, from the SE. Large part of the basin had been filled by Messinian time (late Miocene); the remaining lake was located in southeastern Hungary and neighboring countries. In the Tortonian stage, the three fluvial systems advanced concomitantly (with small-scale, high-frequency cycles), toward the basin center. A significant relative lake-level drop occurred in the Messinian, which induced large-scale erosion and fluvial incision and generated an unconformity surface that provides a major division in the Pannonian strata; it appears as a significant stratigraphic divide that separates two different stages in the history of the Pannonian Basin. In the upper Messinian-Pliocene stage, the basin underwent a tectonic inversion; the shallow lake was filled up rapidly by lowstand turbidites and prograding delta-slope sediments. The inversion continues up to the present day. Turbidites and lowstand prograding wedges associated with the Messinian event may be targets for hydrocarbon exploration. Four main stages can be identified in the Upper Miocene-Pliocene basin fill history: (1) Tortonian highstand regression with several low-rank relative lake-level cycles; (2) Messinian lake-level drop, accompanied by the formation of the "Messinian unconformity" and the deposition of a falling-stage systems tract (FST). The "Messinian unconformity" is a composite surface, represented by a subaerial unconformity at the margins, and a basal surface of forced regression in the depocenters; (3) relative rise of lake level, when the FST turned to a lowstand systems tract (LST); (4) tectonic inversion (basinward tilt and marginal uplift) during or at the beginning of the LST.
- 出版日期2015-9
