A regional seismic interpretation ot the on shore Otway Basin has been completed and used to determine the basin's structural history.Sedimentation commenced in the Tithonian-Berriasian with the deposition of the volcanogenic Casterton Formation and continued into the Berriasian-Barremian with the deposition in elongate half graben, of thick fluviolacustrine sediments of the Crayfish Group, typically thickening dramatically towards the bounding faults. The NW to W trend of Crayfish Group depocentres and their major bounding faults suggest that the initial extension direction was N-S to NE-SW in the Late Jurassic-Early Cretaceous. Dextral transtensional movement occurred along the Trumpet Fault in the west of the basin and was complemented by sinistral transtension on the major NNE striking faults of the Torquay Sub-basin in the east during this period.The dip direction of the pre-Barremian bounding faults changes a number of times along the northern margin of the basin. These changes occur across transfer/accommodation zones of complex faulting and folding, not over discrete transfer faults.Faulting and related uplift resulted in partial erosion of the Crayfish Group from a number of structural highs, prior to the Aptian. The half graben faults are overlain by Eumeralla Formation indicating that active rifting had ceased by the Aptian in the onshore Otway Basin. Further erosion occurred following post-Albian faulting and uplift prior to the Paleocene, in particular within the eastern part of the basin.During deposition of the Sherbrook Group in the Late Cretaceous, fault reactivation produced minor, shallow grabens within the older half graben systems. Major movement also continued along the Tartwaup Fault Zone, resulting in basin deepening toward the SW. This fault activity continued into the Paleocene-Early Eocene during deposition of the Wangerrip Group. In the Eocene, the Southern Ocean spreading rates changed from slow to fast, resulting in the late-Early Eocene deltaic sediment of the Upper Wangerrip Group covering some of the earlier extension faults. Compression, resulting in right-lateral wrenching and inversion of previous faults, occurred during the Miocene-Recent. Pliocene-Holocene volcanic activity occurred along zones of weakness related to these fault systems.
This project has been conducted for the General Directorate of Turkish Coal Enterprise. The aim of this study is to understand lignite potential of the basin. Subsurface data (including numerous wells and several seismic lines) provided by TPAO, MTA and TKİ were used. Structure and thickness maps of Oligocene-Miocene-Pliocene units prepared for the basin. Purpose of this work is to understand economical values of lignite seam beds interbedding in the Danişmen Formation (Oligocene-Early Miocene). For this purpose, from bottom to top following maps were prepared: Structural map of the top Osmancık (Oligocene) Formation, thickness map of the Danişmen Formation, paleo-topographic map of unconformity surface which is at the top of the Danişmen Formation, total thickness map of Ergene-Kırcasalih formations (Late Miocene-Pliocene). Finally total thickness map of the lignite layers was prepared. It was the main purpose of the work. Lignite seam layers are located in middle of the Danişmen Formation. Also several stratigraphic correlations were conducted to understand lateral continuation of lignite layers. The first obstacle to reach lignite is thickness of the Ergene and Kırcasalih formations which overlie lignite bearing Danişmen Formation. Main structural event controlling the thickness variation of the Danişmen Formation is Thrace Fault System (Perinçek, 1991); it was active during Middle Miocene. Danişmen Formation extensively or partially was eroded along the fault zone and on the en-echelon folds of the fault system. Amount of erosion is variable and in some areas Danişmen Formation completely was eroded. As a result Ergene Formation lies directly on Osmancık Formation. Lignite layers are also eroded at these localities. Elevated areas related the Thrace Fault System partially was eroded; however these areas were still paleo-elevated areas during the accumulation of Ergene Formation. Onlapping sequence of Ergene Formation is thinner on these areas. At the end of this project, thicker lignite areas were delineated. Addition to this, thin overburden areas on lignite are located. Considering these results, new permit areas were selected. In order to refine this work, a suggested facies map of Danişmen Formation is advise to be prepared.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.