Together but separate: decoupled Variscan (late Carboniferous) and Alpine (Late Cretaceous – Paleogene) inversion tectonics in NW Poland

Abstract. In Europe, formation of the Palaeozoic Variscan orogenic belt, and then the Mesozoic-Cenozoic Alpine-Carpathian orogenic belt led to a widespread inversion events within forelands of both orogenic domains. We used legacy 2D seismic data together with the newly acquired 3D seismic data that for the first time precisely imaged sub-Zechstein (i.e. sub-evaporitic) upper Palaeozoic succession in NW Poland in order to develop quantitative, balanced 2D model of the late Palaeozoic – recent evolution of this area, characterised by a complex pattern of repeated extension and inversion. Four main tectonic phases have been determined: (1) Late Devonian – early Carboniferous extension related to extensional reactivation of Caledonian thrusts, (2) late Carboniferous inversion caused by Variscan orogeny, (3) Permo-Mesozoic subsidence related to the development of the Polish Basin, and (4) its Late Cretaceous – Paleogene inversion. Variscan and Alpine structures form superimposed multilayer inversion system, mechanically decoupled along the Zechstein evaporites.

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New play type, southern Bonaparte Basin-Petrel Sub-basin—WA-442-P and NT/P81 exploration permits

The APPEA Journal ◽

10.1071/aj11041 ◽

2012 ◽

Vol 52 (1) ◽

pp. 525

Author(s):

Margaret Hildick-Pytte

Keyword(s):

Seismic Data ◽

Early Carboniferous ◽

Oil Fields ◽

Source Rocks ◽

Lower Carboniferous ◽

Petroleum Systems ◽

Seismic Data Acquisition ◽

Early Palaeozoic ◽

Hydrocarbon Charge ◽

3D Seismic Data

Recent investigation, including mapping re-processed seismic data, suggests there is deeper hydrocarbon potential in the WA-442-P and NT/P81 exploration permits beneath the Early Carboniferous Tanmurra Formation horizon. Earlier interpretation of the area showed tilted fault blocks commonly thought of as economic basement in the vicinity of the Turtle and Barnett oil fields and extending to the northwest to connect with the Berkley Platform. The deep-gas play type is structural and is believed to be two nested three-way dip anticlines developed against a large bounding fault to the northeast, with axial trends northwest to southeast, and axial plane curving towards the northeast for the deeper structure. This play type is believed to be associated with structural compression and movement along the master fault with incremental re-activation most recently during the Cainozoic as recorded in overlying sediments. The Nova Structure and the deeper Super Nova structure have closures of about 450 and 550 km2, respectively. The sediments beneath the Nova horizon are believed to be of Devonian Frasnian-Famennian age but have not been drilled offshore in the Southern Bonaparte Basin (Petrel Sub-basin). Earlier work suggests that there are two petroleum systems present in the southern Bonaparte Basin, a Larapintine source from Early Palaeozoic Devonian to Lower Carboniferous source rocks, and a transitional Larapintine/Gondwana system sourced from Lower Carboniferous to Permian source rocks. Hydrocarbon charge for the structures is most likely from the Larapintine source rock intervals or yet to be identified older intervals associated with the salt deposition during the Ordovician and Silurian. Independent estimates place close to 7 TCF (trillion cubic feet) of gas in the Nova Structure. New 3D seismic data acquisition is planned over the structures to better define the geology and ultimately delineate well locations.

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Salt in the Vulcan sub-basin, NW Australia: observations from high-quality 3D seismic data and implications for palaeogeography

The APPEA Journal ◽

10.1071/aj20068 ◽

2021 ◽

Vol 61 (2) ◽

pp. 684

Author(s):

Simon Molyneux ◽

Stephen Doyle

Keyword(s):

Seismic Data ◽

Spatiotemporal Distribution ◽

3D Seismic ◽

High Quality ◽

Regional Tectonic ◽

Tectonic Features ◽

First Time ◽

3D Seismic Data ◽

Nw Australia

The Vulcan sub-basin is one of the few places in Australia where tectonic features (i.e. diapirs) associated with a mobile substrate can be found. In this presentation one of these features, the Paqualin diapir, and its environs will be described and discussed using the new regional NOVAR MC3D prestack depth migrated seismic dataset. The extent of the NOVAR MC3D seismic dataset makes it possible, for the first time, to integrate the observation of c. 600m of interbedded halite and anhydrite in the Paqualin-1 well, local fault geometries indicative of the movement of a mobile layer and regional tectonic features consistent with the presence of a mobile substrate. In this presentation the observations will be integrated with global analogues, regional palaeogeographic interpretations to refine models for the origin and spatiotemporal distribution of mobile layers in the Vulcan sub-basin.

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