The Tarim Mega Impact Event: A Permian (~290 Ma) Mega-Impact Triggering Global Magmatism, the Artinskian Warming Event, and the Central Asian Arc-LIP Belt

Tao Fang

We propose that an oblique mega-impact by a ferronickel asteroid (~180×100×90 km, 22 km/s, incidence angle 24°) that occurred at ~290 Ma in the present-day Tarim Basin can, through the "thin-target penetration" mechanism, attempt to unify within a single physical framework: (1) the Tarim Large Igneous Province (TLIP) flood basalts; (2) the Pamir–Iran–Turkey arcuate mafic–ultramafic magmatic belt; (3) the Artinskian Warming Event (AWE) global temperature rise and oceanic anoxia; and (4) the Central Asian–Middle Eastern arcuate geomorphic pattern. These phenomena are attributed in the conventional framework to multiple independent mantle plumes, back-arc extension, and subduction zone events.

The v3.4 quantitative model shows: the impactor penetrated through 35 km of crust into the mantle, depositing ~2049 YJ of shock energy, and through a four-stage chain reaction (shock compression → stress-gradient comminution heating → distributed decompression melting → expansion-pressure-driven sheet flow/conduit flow) produced a total melt of ~24.14 million km³. The main eruption period of ~0.88 years (~11 months) transported ~7.013 million km³ of magma over long distances to the Afghanistan–Iran–Turkey region (3.4 million km², average thickness 2063 m, flow distance 4300 km) via the Pamir channel (200 km wide × 150 m thick surface sheet flow, Manning open-channel flow n=0.035, v≈21 m/s), driven by 3.73 GPa overpressure (lithostatic 0.93 + expansion 2.80 GPa) along pre-existing structural weaknesses (Paleo-Tethys suture zone). Melt is driven by this overpressure as Manning open-channel flow over 4300 km surface; the extreme flux (Q_pamir=6.3×10⁸ m³/s) creates self-insulation (f_insul=0.98) where surface solidification forms an insulating crust preventing interior cooling, enabling long-distance transport. The near-field Tarim identifiable volcanic rocks + crater cavity fill amount to ~1.143 million km³ (crater fill 0.434 + main crater 0.473 + near-field 0.236), with an additional 0.158 million km³ in the mid-field; total volcanic rocks ~7.93 million km³, I:E ratio 2.06:1. Fragmentation energy is accounted for in three tiers: E_mech=410 YJ (mechanical fragmentation) → E_heat=287 YJ (converted to heat, 70% efficiency) → E_eff=29 YJ (effective persistent temperature rise, 10% of heat, ΔP_frag=0.11 GPa), with extraction efficiency f_extract=33% (R_heat=164 km, ΔT=361 K, F_melt=0.75). SO₂ release 2821 Gt (near-field 1685 + far-field 1136, stratospheric injection 758 Gt), CO₂ release 11,420 Gt, CH₄-C release 1756 GtC (only shallow intrusives — dikes/sills emplaced <5 km depth, ~8% of total intrusive volume — contribute to contact metamorphism CH₄).

This model may uniformly account for multiple anomalies that the mantle plume model struggles to explain: absence of pre-eruption doming, absence of a plume track chain, extremely short main eruption period (~0.88 years ≈ 11 months vs. 10⁶–10⁷ years), non-thermal-plume character of the mantle transition zone anomaly, anomalously hydrous source region (~520 ppm), spatial organization of the arcuate LIP belt, and global synchronicity of the AWE. We propose 10 independently testable predictions, including shock metamorphic PDFs within the crater interior (r<125 km) (decisive; verification targets are Tarim Basin borehole cores + southern margin of the Kuruk Tagh mountains bedrock), the Dal'ny Tulkas extraterrestrial chromite layer (decisive), an 11±2 km-thick concealed melt layer beneath the Tarim central trough, and a mafic-leaning lower crustal layer with Vp≥6.5 km/s beneath the Iranian Plateau.