Aeromagnetic data from the Assarag area (Ouzellagh-Siroua salient, central Anti-Atlas, Morocco): Implications for the Imourkhssen porphyry mineralization

The Assarag region is located in the northern part of the Ouzellagh-Siroua salient, being a segment of the central
Anti-Atlas basement bulging within the High-Atlas Belt of Morocco. It consists mainly of the Late Ediacaran
Magmatic Suites (LEMS) of the Ouarzazate Group (580-539 Ma). The LEMS comprise high potassic calc-alkalic I type
granitoids that host the Imourkhssen Cu-Mo-Au-Ag porphyry mineralization. The aeromagnetic data from
the Assarag region led to describe structural features in the LEMS based on their magnetic footprints. aeromagnetic
datasets were processed using several transformations including the reduction to pole (RTP), Upward
continuation (UC), Tilt derivative (TD), Center for Exploration Targeting (CET) and Euler deconvolution (ED)
filters. RTP, TD and CET transformations allowed to map NNE-SSW, NNW-SSE and NE-SW trending faults in the
north, in addition to a curved magnetic halo in the southwestern part of the Assarag area. The UC filter subdivided
the Assarag area into two magnetic morpho-structural domains: a northern region with low-magnetic
features, and a southern high-magnetic region with positive curved trending patterns. The ED results match
and support the extracted lineaments. The aeromagnetic data were also processed by a 2D Spatio-Spectral
Feature Extraction and Selection tool (SFES2D) using two-dimensional continuous wavelet transformations
(2D CWT), principal component analysis (PCA) and independent component analysis by kurtosis and negentropy
methods (k-ICA and n-ICA). The PCA results corroborate previously extracted lineaments and highlight a new
ENE-WSW oriented structure. Meanwhile, the CWT allowed us to conclude that NNE, NNW and NE trends are
shallow and emphasized deep NW-SE and ENE-WSW structures in the southern part of the Assarag area. ICA
emphasizes the ENE lineament and matches the previous results. We herein define the deeper ENE trend as a part
of the South Atlas Fault (SAF), which crosscuts the LEMS in the study area. Meanwhile, the shallow NE-SW and
NNE-SSW tectonic features likely served as conduits for the ore-bearing fluids, leading to the Imourkhssen Cu-
Mo-Au-Ag mineralization. Consequently, these directions present a valuable approach for guiding mineral
exploration in the Ouzellagh-Siroua salient, from prospect to regional scales.