New stratigraphic and sedimentological investigations on the Middle Eocene–Early Miocene continental successions in southwestern Sardinia (Italy): Paleogeographic and geodynamic implications
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- 作者：Sebastiano Barca ; Luca Giacomo Costamagna
- 关键词：Cixerri Fm. ; Continental successions ; Pyrenean Orogeny ; Sardinian Rift ; Stratigraphy ; Sedimentology ; SW Sardinia
- 刊名：Comptes Rendus Geoscience
- 出版年：2010
- 出版时间：February 2010
- 年：2010
- 卷：342
- 期：2
- 页码：116-125
- 全文大小：840 K
文摘
In SW Sardinia, the continental Tertiary successions referred up to now to the Cixerri Fm. (Middle Eocene–Lower Oligocene?) have been investigated. Sedimentological analysis suggests these deposits lied down in fluvial environments and comprised between distal braided streams passing eastward to meandering streams/coastal environments (?) under sub-arid climates. The scrutinization of the Cixerri Fm. westernmost successions allowed one to split locally the upper from the lower part based on sedimentological and mineralogical features and indirect dating. Unfortunately, this separation cannot be set everywhere. The few upper outcrops plainly evidenced and well-constrained have been newly named Flumentepido Fm. and assigned to Late Oligocene–Early Miocene: they figure out alluvial fans and proximal braided rivers. This way, the SW Sardinia Tertiary continental sedimentation extends its persistence, contemporaneously changing its tectostratigraphic meaning: from a molassoid context related to the Pyrenean wedge dismantling (Eocene–Oligocene) to a rift-margin succession connected with the opening of the Algero-Provençal back-arc basin due to the Apennine subduction in Oligocene–Miocene times.