Geopersia

Geopersia

Sparsity-based Regularization of Geophysical Time-domain Electrical Resistivity and Induced Polarization Data: A Strategy for Imaging Takhte-Gonbad Porphyry Cu Deposit

Document Type : Research Paper

Authors
1 School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran
2 Institute of Geophysics, University of Tehran, Tehran, Iran
Abstract
This research employs a combined geophysical approach, utilizing electrical resistivity tomography (ERT) and induced polarization (IP) imaging, to characterize the subsurface architecture and identify copper-bearing zones at the Takhte-Gonbad porphyry copper deposit within the Kerman metallogenic belt, Iran. The acquired field data were inverted using two distinct methodologies: conventional Tikhonov regularization and sparsity-based regularization. The resulting inverse models successfully delineated two principal E-W trending mineralized zones, which are distinguished by coherent low-resistivity and high-chargeability anomalies diagnostic of disseminated sulfide mineralization. These geophysical signatures exhibit a strong spatial correlation with surface-mapped zones of phyllic and argillic alteration and are further validated by borehole assay data confirming local copper grades exceeding 1%. A comparative assessment of the inversion results indicates that sparsity-based regularization produces subsurface models with sharper lithological boundaries and improved delineation of compact, high-contrast ore bodies, making it particularly effective for resolving localized features at the deposit scale. In contrast, Tikhonov regularization yields smoother models that are better suited for representing broader, regional-scale geological structures. Overall, both inversion approaches are capable of resolving the main subsurface features; however, they emphasize different aspects of the subsurface due to their inherent regularization properties. Accordingly, the choice between them should be guided by the geological objectives rather than interpreted as a general superiority of one method over the other.
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Article Title Persian

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Articles in Press, Accepted Manuscript
Available Online from 04 June 2026

  • Receive Date 13 November 2025
  • Revise Date 26 April 2026
  • Accept Date 04 June 2026