Search

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Field data and seismic reflection profiles of various resolutions, calibrated by deep well logs, have been used to unravel the tectonic evolution of the Crati Basin (southern Italy). The study area is located in the northern portion of the Calabrian Arc, a well-developed arc-shaped feature of the circum-Mediterranean belts, consisting of a series of ophiolite-bearing tectonic units and overlying basement nappes. NW–SE oriented left-lateral strike-slip faults exerted a major control on the tectonic evolution of northern-central Calabria, from Middle Miocene to Lower Pleistocene times. Such faults, arranged in an en-échelon geometry and dissecting the pre-existing Late Oligocene–Early Miocene orogenic belt, led to a structural setting including major N-S striking synforms – as the offshore Paola Basin and the Crati Basin are interpreted based on our results – separated by a broad antiformal ridge. Since the Middle Pleistocene, both E- and W-dipping normal faults developed in the southernmost sector of the Crati Basin, probably as a consequence of both uplift of the orogenic edifice and Tyrrhenian back-arc extension. The pre-existing regional strike-slip faults became inactive in this sector of the belt. However, working as persistent barriers, it is envisaged here that they inhibited the southern propagation of the newly formed normal faults, which therefore propagated towards the north. A minimum value of cumulative displacement of ca. 600m has been unraveled for the central sector of the Crati Basin since Middle Pleistocene times. This yields a vertical strain rate of ca. 0.9mm/y during the last 700ka. [ABSTRACT FROM AUTHOR]

Abstract: The Crati basin is a tectonic depression developed between the Coastal Range and the Sila Massif and is characterised by a sedimentary succession ranging between Late Miocene to Holocene age. Basin cover can be subdivided into a series of stratigraphic intervals bounded by angular unconformities. The general basin architecture is mainly controlled by N–S striking normal faults (the Crati Fault System) cropping out along both basin margins. These faults formed since the Middle Pliocene in the southern part of the basin and propagated northwards, where they developed during Middle–Late Pleistocene. The occurrence of several earthquakes along N–S striking faults, suggest their still ongoing activity. The northernmost part of the Crati basin, bordered by the 30 km long Pollino fault, is thought to be characterised by an important seismic gap; this contrasts with the geological evidences of Quaternary fault activation of both the central part of the Pollino fault and some NNW–SSE striking normal faults. We propose that the NNW–SSE striking faults represent the northernmost prolongation of the Crati Fault System, a large scale active crustal rift related to the Tyrrhenian spreading. These faults mechanically interacted with the Neogene Pollino fault and determined the almost contemporary activation of the central part of this structure, because of stress triggering phenomena, as suggested by the Coulomb failure stress changes. [Copyright &y& Elsevier]