LOWER DEVONIAN: DEPOSITIONAL MODEL. REGGANE BASIN. SOUTHWESTERN ALGERIA

摘要

The present study provides an integrated stratigraphy of the Lower Devonian of the southestem Reggane Basin, Bled El Mass. This is important to establish a standard section allowing an interregional correlation as well as an interpretation of single environmental conditions, their changes through time and their geographical extent. Numerous sections have been investigated in this area, in addition to data from other profiles in the basin. Investigation of the sedimentary sequence is based on a analysis of events. Initially many events are diachronous, whereas others are difficult to define and do not show a wide geographic distribution. For palaeoecological reasons, correlation is not possible or very difficult. The discussion of events leads to a compound picture of the evolution of the depositional sequence, allowing the reconstruction of palaeoenvironmental changes. A sequence from the base of Lower Devonian, up to the lower Upper Emsian, is investigated concerning the controlling factors of sedimentation. The cyclicity of lithology is investigated by Magnetic susceptibility (MSEC). It can be shown that sedimentation is forced by orbital cycles, mainly by the precession of the cycles.