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<p>Cratonic basins preserve some of Earth’s most deeply buried petroleum systems, yet their crystalline basements and thermo–tectonic histories remain difficult to image. The Tarim Basin (NW China) exemplifies these challenges and opportunities. Here we test whether crustal uplift is systematically coupled with magnetization loss (demagnetization) by performing a basin-scale 3-D inversion of aeromagnetic anomaly data to recover crustal magnetization (M) and by quantifying spatial relationships between magnetization and mapped basement uplifts (Bachu, Tazhong, Tabei, Tadong, and Southeastern). We analyze depth slices at 5–30&#xa0;km and diagnostic sections, and compare uplift and depression domains using a robust uplift–depression magnetization contrast, ΔM = median(M_uplifts)-median(M_depressions). Most uplifts (Tazhong, Tadong, and Southeastern) exhibit consistently negative ΔM at 20–30&#xa0;km, indicating volumetric low-magnetization (low-M) bodies that strengthen with depth. Bachu shows a mixed pattern (weak margins but a relatively stronger core), while Tabei displays negative ΔM at 10–20&#xa0;km and near-zero contrast at 30&#xa0;km, implying spatially heterogeneous modification among uplift blocks. To evaluate geometry-following coupling, we define low-M masks using the basin-wide lower quartile (Q25) of M and compute Q25–Jaccard overlaps with uplift domains and the Tarim Large Igneous Province (TLIP) footprint, complemented by distance-to-uplift-edge ΔM profiles. Overlap and proximity metrics show positive and generally increasing coincidence between low-M masks and uplift interiors from 10 to 30&#xa0;km, and a secondary but consistent association with TLIP. These depth-coherent, uplift-centered low-M volumes are most consistent with thermal demagnetization driven by Permian plume-related magmatism, Curie-isotherm shallowing, and hydrothermal alteration, whereas purely lithologic controls, remanence cancellation, or structural disruption alone are less able to explain the systematic depth dependence and spatial coherence. Beyond Tarim, this uplift–demagnetization coupling provides a transferable diagnostic for mapping thermally modified domains in cratonic interiors and has direct implications for deep exploration by highlighting uplift cores where elevated palaeo-temperatures and fluid–rock interaction may have re-engineered source–reservoir systems.</p>

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Coupling between crustal uplift and magnetic demagnetization in the Tarim Basin

  • 期刊论文

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  • 发表日期：

    2026年2月12日

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  • Bing Xu,
  • Chongjin Zhao,
  • Luolei Zhang,
  • Peng Yu

摘要

Cratonic basins preserve some of Earth’s most deeply buried petroleum systems, yet their crystalline basements and thermo–tectonic histories remain difficult to image. The Tarim Basin (NW China) exemplifies these challenges and opportunities. Here we test whether crustal uplift is systematically coupled with magnetization loss (demagnetization) by performing a basin-scale 3-D inversion of aeromagnetic anomaly data to recover crustal magnetization (M) and by quantifying spatial relationships between magnetization and mapped basement uplifts (Bachu, Tazhong, Tabei, Tadong, and Southeastern). We analyze depth slices at 5–30 km and diagnostic sections, and compare uplift and depression domains using a robust uplift–depression magnetization contrast, ΔM = median(M_uplifts)-median(M_depressions). Most uplifts (Tazhong, Tadong, and Southeastern) exhibit consistently negative ΔM at 20–30 km, indicating volumetric low-magnetization (low-M) bodies that strengthen with depth. Bachu shows a mixed pattern (weak margins but a relatively stronger core), while Tabei displays negative ΔM at 10–20 km and near-zero contrast at 30 km, implying spatially heterogeneous modification among uplift blocks. To evaluate geometry-following coupling, we define low-M masks using the basin-wide lower quartile (Q25) of M and compute Q25–Jaccard overlaps with uplift domains and the Tarim Large Igneous Province (TLIP) footprint, complemented by distance-to-uplift-edge ΔM profiles. Overlap and proximity metrics show positive and generally increasing coincidence between low-M masks and uplift interiors from 10 to 30 km, and a secondary but consistent association with TLIP. These depth-coherent, uplift-centered low-M volumes are most consistent with thermal demagnetization driven by Permian plume-related magmatism, Curie-isotherm shallowing, and hydrothermal alteration, whereas purely lithologic controls, remanence cancellation, or structural disruption alone are less able to explain the systematic depth dependence and spatial coherence. Beyond Tarim, this uplift–demagnetization coupling provides a transferable diagnostic for mapping thermally modified domains in cratonic interiors and has direct implications for deep exploration by highlighting uplift cores where elevated palaeo-temperatures and fluid–rock interaction may have re-engineered source–reservoir systems.