Tectonic and Hydrothermal Activities in Debagh, Guelma Basin (Algeria)

Abstract

Quaternary and Pliocene travertines, deposited from hot springs, can reveal much about neotectonic and hydrothermal activity. The aim of this work is the understanding of the actual tectonic activity in the Guelma Basin and in one of its spa structures. Gravity data were collected during a field study in the Hammam Debagh (HD) area and then analyzed to better highlight the architecture of its subsurface underlying structures. This analysis was performed by means of a Bouguer anomaly, upward continuations, and residual and derivative maps. Comparison of gravity maps, field geology, geomorphic observations, and structural maps allowed us to identify the major structural features in the Hammam Debagh. As a result, we confirm the position of the Hammam Debagh active fault which is superimposed to the hydrothermal active source in the NW-SE direction characterized by a negative gravity anomaly.

Active Faulting Geometry and Stress Pattern Near Complex Strike‐Slip Systems Along the Maghreb Region: Constraints on Active Convergence in the Western Mediterranean

“…It depicts one of a series of long, E-W right-lateral strike-slip crustal fault system (Aoudia et al, 2000;Jallouli et al, 2013) that is characteristic for northern Africa and extends over 200 km from the high mountains of Debagh (in Algeria; Meghraoui, 1988;Vila, 1980) in the west to Thibar region (in northern Tunisia) in the east. This E-W major fault zone is reported clearly in previous geological studies (e.g., Bounif et al, 1987;Guiraud, 1977;Maouche et al, 2013;Meghraoui, 1988;Rouvier, 1977;Vila, 1980), geophysical data (e.g., Amiri et al, 2011;Harbi et al, 1999) as a dextral strike-slip fault system. Moreover, it is characterized by neotectonic and seismotectonic activities (Harbi et al, 1999)…”

“…This E‐W major fault zone is reported clearly in previous geological studies (e.g., Bounif et al, ; Guiraud, ; Maouche et al, ; Meghraoui, ; Rouvier, ; Vila, ), geophysical data (e.g., Amiri et al, ; Harbi et al, 1999) as a dextral strike‐slip fault system. Moreover, it is characterized by neotectonic and seismotectonic activities (Harbi et al, ) and associated with en echelon folds along its westernmost fault segment and pull‐apart basins along its easternmost segment (Maouche et al, ; Figure ).…”

“…In addition, the upper mantle can also play an action on surface deformation, where the shear heating due to rise of magmas and/or hot fluids would inevitably cause strain localization in the deeper parts of strike‐slip faults, as often shown in the field for crustal shear zones (Leloup et al, ). Therefore, we suggest a supplementary source of stress of mantle order that can accumulate along the crustal strike‐slip faults of the Maghreb, such as the DT and Yusuf shear zones, which are associated by Neogene volcanism and hydrothermal activities (Bousquet, ; Maouche et al, ; Maury et al, 2000).…”

“…Several geological studies reveal the presence of magmatic rocks, diapiric Triassic salt outcrop (Maury et al, ; Rouvier, ; Vila, ), and hydrothermal activities (Maouche et al, ) along this major deep‐seated fault system. The E‐W trending master shear zone of Debagh‐Thibar (DT) crossing the Guelma Basin (Harbi et al, ; Maouche et al, ; Meghraoui, ) combines and splays toward northern Tunisia with NE‐SW trending features.…”

“…The normal seismic event in the Guelma zone (Aoudia et al, ) shows the reactivation of N‐S to NNW‐SSE bounding normal faults that constitutes the extensional duplex and intersects the subparallel main shear faults. Therefore, a local crustal extension (Maouche et al, ) occurs between two overlapping E‐W dextral strike‐slip faults under a regional‐scale NW‐SW compression. The stress tensor inversion of the largest‐magnitude earthquakes ( M > = 4.5) for the eastern Tell region (Figure ) gives a strike‐slip tectonic regime with a slight extensional component and NNW‐SSE oriented S Hmax (N154°E ± 9.4°).…”