The Siberian flood basalts (SFB) erupted at the end of the Permian period (∼250 Ma) in response to a deep-rooted mantle plume beneath the Siberian Sub-Continental Lithospheric Mantle (SCLM). Plume-lithosphere interaction can lead to significant changes in the structure and chemistry of the SCLM and trigger the release of metasomatic material that was previously stored within the stable craton. Here, we investigate the nature of the Siberian-SCLM (S-SCLM) by measuring nitrogen abundances and isotopes (${\delta }^{15}$N) in 11 samples of two petrologically-distinct suites of peridotitic xenoliths recovered from kimberlites which bracket the eruption of the SFB: the 360 Myr old Udachnaya and 160 Myr old Obnazhennaya pipes. Nitrogen isotope (${\delta }^{15}$N) values range from -5.85 ± 1.29‰ to +3.94 ± 0.63‰, which encompasses the entire range between depleted Mid-Ocean Ridge Basalt (MORB) mantle (DMM; -5 ± 2‰) and plume-derived (+3 ± 2‰) endmembers. In addition, we present neon (n=7) and argon (n=8) abundance and isotope results for the same two suites of samples. The ²⁰Ne/²²Ne and ²¹Ne/²²Ne range from atmospheric-like values of 9.88 up to 11.35 and from 0.0303 to 0.0385, respectively, suggesting an admixture of DMM and plume-derived components. Argon isotopes (⁴⁰Ar/³⁶Ar) range from 336.7 to 1122 and correlate positively with ⁴⁰Ar contents. We show that volatile systematics of Siberian xenoliths: (1) exhibit evidence of ancient metasomatic and/or recycled signatures, and (2) show evidence of subsequent plume-like re-fertilization, which we attribute to the emplacement of the SFB. Metasomatic fluids are highly enriched in radiogenic gases and have elevated Br/Cl and I/Cl values, consistent with an ancient subducted crustal component. The metasomatic component is marked by light N isotope signatures, suggesting it may be derived from an anoxic Archean subducted source. Taken together, these N₂-Ne-Ar isotope results suggest that mantle plume impingement has profoundly modified the S-SCLM, and that N, Ne and Ar isotopes are sensitive tracers of metasomatism in the S-SCLM. Metasomatic fluids that permeate the S-SCLM act to archive a “subduction-fingerprint” that can be used to probe relative volatile-element recycling efficiencies and thus provide insight into volatile transport between the surface and mantle reservoirs over Earth history.

西伯利亚洪水玄武岩（SFB）是在二叠纪末期（〜250 Ma）爆发的，这是对西伯利亚次大陆岩石圈地幔（SCLM）下方根深蒂固的地幔柱的反应。羽-石圈相互作用可能导致SCLM的结构和化学发生重大变化，并触发释放以前储存在稳定克拉通中的交代物质。在这里，我们通过测量氮丰度和同位素来研究西伯利亚SCLM（S-SCLM）的性质（${\delta }^{15}$N）从金伯利岩中发现的两个岩石学上截然不同的套件的11个样品中，这些金伯利岩与SFB的喷发有关：360迈尔的旧Udachnaya和160迈尔的旧Obnazhennaya。氮同位素（${\delta }^{15}$N）值的范围是-5.85±1.29‰至+3.94±0.63‰，涵盖了枯竭的中洋海底玄武岩（MORB）地幔（DMM; -5±2‰）和羽状衍生的（+3± 2‰）端成员。此外，对于相同的两组样品，我们还给出了氖（n = 7）和氩气（n = 8）的丰度和同位素结果。在²⁰ NE / ²² Ne和²¹ NE / ²²从氖范围大气样到11.35和从0.0303到0.0385，分别的9.88向上值，提示DMM和羽流衍生的组分的混合物。氩同位素（⁴⁰ Ar / ³⁶ Ar）的范围为336.7至1122，与⁴⁰正相关Ar含量。我们显示出西伯利亚异岩的挥发性系统：（1）表现出古老的交代和/或再生特征的证据，（2）表现出随后羽状再肥的证据，这归因于SFB的位置。变质流体富含放射源气体，并且具有较高的Br / Cl和I / Cl值，这与古老的俯冲地壳成分一致。缔合组分由轻的N同位素特征标记，表明它可能来自缺氧的太古宙俯冲源。总而言之，这些N ₂-Ne-Ar同位素结果表明，地幔柱撞击已深刻地改变了S-SCLM，而N，Ne和Ar同位素是S-SCLM中交代作用的敏感示踪剂。渗透到S-SCLM的变质流体起到存档“俯冲指纹”的作用，可用于探测相对挥发性元素的回收效率，从而洞悉地球历史上地表和地幔储层之间的挥发性运移。