Papers by Nasreddine Bournas
3D Inversion of Aeromagnetic Data for Basement Mapping of Hassi Berkine – Illizi Basins, Algerian Sahara
B05 3D INVERSION OF AEROMAGNETIC DATA FOR BASEMENT MAPPING OF HASSI BERKINE – ILLIZI BASINS ALGER... more B05 3D INVERSION OF AEROMAGNETIC DATA FOR BASEMENT MAPPING OF HASSI BERKINE – ILLIZI BASINS ALGERIAN SAHARA 1 N. BOURNAS 1 H. BOUBEKRI 2 L. DOUIDI 3 J.D. FAIRHEAD 4 AND J.M. JACQUES 4 1 University of Boumerdes Department of Geophysics Ave de l’independence Boumerdes 35000 Algeria 2 Univeriste de Bab Ezzouar Algeria 3 SONATRACH Algeria. 4 GETECH U.K. Abstract 2D and 3D inversion techniques of aeromagnetic data are playing an important role in the interpretation routine by providing rapid estimates of magnetic sources location and their spatial distributions. For basement areas these techniques are generally aimed to detect magnetic
Detection of Major Active Faults of Northern Algeria Using Aeromagnetic Data
Interpretation of Airborne Magnetic Maps - a Case History from Hoggar Regio South of Algeria
62nd EAGE Conference & Exhibition, 2000
The Aeromagnetic Map of Hoggar (Tuareg Shield, Algeria) – Processing and Interpretation
66th EAGE Conference & Exhibition, 2004
E030 THE AEROMAGNETIC MAP OF HOGGAR (TUAREG SHIELD ALGERIA). PROCESSING AND INTERPRETATION 1 N. B... more E030 THE AEROMAGNETIC MAP OF HOGGAR (TUAREG SHIELD ALGERIA). PROCESSING AND INTERPRETATION 1 N. BOURNAS 1 M. HAMOUDI 2 A. GALDEANO 3 K. OUZEGANE 2 AND J.R. KIENAST 4 1 University of Boumerdes Department of Geophysics Ave de l’independence Boumerdes 35000 Algeria 2 Univeriste de Bab Ezzouar Algeria 3 IPGP France 4 Universite Paris VII France Abstract The Tuareg shield represents a part of the transsaharan Panafrican belt and is composed of Hoggar Air and the Iforas mountains. Historically the Hoggar is subdivided into three main structural blocks with different geology and separated by two mega shear zones (Bertrand and
SPM Discrimination in Airborne TDEM Data - A Case Study from the Maniitsoq Area, Southwestern Greenland
Proceedings, 2016
SPM effects, which are mainly caused by fine-grained iron particles such as maghemite and magneti... more SPM effects, which are mainly caused by fine-grained iron particles such as maghemite and magnetite constitute a geological noise in modern airborne transient Time Domain EM (TDEM) systems. Therefore, their identification and discrimination is important when exploring for bedrock conductors associated with metallic mineralisation such as nickel and sulphides. In the transient TDEM data, they are manifested by a power law decay fit at mid-late time close to -1. In this paper, we describe other approaches for identifying and discriminating SPM anomalies observed in the transient TDEM data from Greenland, including a) innovative dual-EM receiver configuration (vertical EM gradiometer), and b) a multiple criteria pattern recognition approach, based on maximum likelihood algorithm. As a result, many SPM-related detected by airborne TDEM surveys were identified and were hence discriminated from further follow-up. Diamond drill testing in 2016 performed on selected targets that were categorized as non-SPM related, has confirmed their link to bedrock conductors and sulphide mineralization.
Preliminary Helicopter EM Survey Results over the Brandon Channel and Assiniboine Delta Aquifers, Brandon, Manitoba
Summary VTEM helicopter time-domain EM survey results over the Brandon Channel and Assiniboine De... more Summary VTEM helicopter time-domain EM survey results over the Brandon Channel and Assiniboine Delta aquifers, near Brandon, Manitoba, have been studied using unconstrained layered earth modeling. The resistive sand and gravel layers are distinguished from the more conductive shale basement and reveal localized thickening from blind gravel channels cut into its floor. They further distinguish a lower aquifer separated by a conductive clay layer from shallow sands of the Assiniboine Alluvial aquifer and the Assiniboine Delta Aquifer. The Brandon Channel is mapped, including a secondary channel further north. The western extent of Assiniboine Alluvial aquifer is defined and evidence for the Pierson Valleyaquifer extending west from Brandon is also indicated.
Delineation of a Porphyry Copper-Gold system using 3D DCIP, CSAMT and MT surveys-Case history, the Santa Cecilia Deposit, Chile
Delineation of Graphitic bedrock conductors in northeastern Mozambique using VTEMplus
ASEG Extended Abstracts, 2019
Impact of airborne geophysical surveys on the exploration of gold mineralization in Burkina Faso
SEG Technical Program Expanded Abstracts 2019, 2019
ZTEM and magnetic interpretation results over the La Esperanza epithermal silver and precious and base metals project, Zacatecas and Durango States, Mexico
SEG Technical Program Expanded Abstracts 2019, 2019
SEG Technical Program Expanded Abstracts 2018, 2018
In this paper, we propose a new exploration strategy for detecting pipe-like structures from airb... more In this paper, we propose a new exploration strategy for detecting pipe-like structures from airborne TDEM data. We first apply the Keating's pattern recognition technique to the EM resistive limit calculated from the early and midtime decay channels and to the magnetic analytic signal for predicting conductive and magnetic pipes. The automated detection procedure yielded numerous solutions, whose number is downsized after a careful screening and finetuning of the obtained results. Further, the selected targets are classified into several categories according to their EM, magnetic and IP signatures. Finally, we perform 3D MVI and 1D EM inversion on selected targets to determine the size, the depth and the magnetic and electrical properties of these targets.
Journal of Applied Geophysics, 2017
Superparamgnetic (SPM) effects caused by the viscous magnetic properties of singledomain nanoscal... more Superparamgnetic (SPM) effects caused by the viscous magnetic properties of singledomain nanoscale particles (magnetite and maghemite minerals) have been observed in VTEM data acquired over the Maniitsoq project area located in southwestern Greenland. These SPM effects, which constitute a major geological noise, manifest themselves as slowly decaying EM response at late times yielding elevated time constant values that can be misinterpreted to be caused by strong conductors such as Ni-sulphide mineralized bodies. Therefore, their identification and discrimination from conductive sources response is crucial before any follow-up actions. In this paper, we describe the effectiveness of an innovative dual EM receiver for attenuating SPM effects, and the use of a robust multicriteria discrimination approach and an enhanced predictive technique that are used for identifying and discriminating the SPM effects from the conductive sources response observed in VTEM data of Greenland. The proposed approach applied to the VTEM data collected between 2012 and 2015 has allowed discriminating approximately 50% of
Airborne geophysical survey of northeastern Burkina Faso: New insights into the mineral potential of the Birimian basement
SEG Technical Program Expanded Abstracts 2016, 2016
Evidence and identification of SPM in airborne TDEM data from Greenland
SEG Technical Program Expanded Abstracts 2016, 2016
VTEM interpretation results and implications for graphite, Cu-Ni and Cr mineralization-A case study from the Mazeze area, north-eastern Mozambique
Аэроэлектромагнитная технология ZTEM для глубинного изучения недр
Predicting VMS and porphyry copper-gold mineralization using VTEM, gamma ray and Landsat OLI 8 imagery- A case study from the Asmara VMS area, Eritrea
SEG Technical Program Expanded Abstracts 2015, 2015
On January 19 TH , 2012, Zenyatta Ventures Ltd. (Zenyatta) announced the discovery of a very rare... more On January 19 TH , 2012, Zenyatta Ventures Ltd. (Zenyatta) announced the discovery of a very rare type of hydrothermal graphite deposit on its Albany Project. The discovery was based on drill testing of anomalies identified by airborne electromagnetic survey flown in 2010 by Geotech Ltd. using its prototype VTEM MAX time-domain EM system. Crone Geophysics & Exploration Ltd. (Crone) was contracted by Zenyatta to perform surface time-domain EM (TDEM) surveys on the Property during February and March 2013. Crone targeted the drill-confirmed East and West graphitic breccia pipes using an in-loop and out-ofloop configuration to couple with their top and steeply dipping edges, respectively, and successfully outlined their lateral extents.
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Papers by Nasreddine Bournas