We document magnetic mineral diagenesis with high‐resolution magnetic susceptibility, hysteresis, isothermal remanent magnetization, and other rock magnetic measurements through a shallow sulfate‐methane transition (SMT) at Perseverance Drift—a high‐accumulation rate Holocene biosiliceous Antarctic marine sediment deposit. The structure of the SMT is defined with porewater measurements from the same core, allowing direct comparison. Dissolution of the detrital (titano)magnetite assemblage, with preferential dissolution of stochiometric magnetite, occurs in the upper SMT. Higher coercivity magnetic minerals dissolve more slowly, continuing to dissolve through the entire SMT and could be a source of ferric iron for microbial respiration following exhaustion of porewater sulfate, as suggested by accumulation of porewater ferrous iron below the SMT. Superparamagnetic ferrimagnetic mineral enrichment/depletion occurs in three phases through the SMT and is coupled tightly to the availability of dissolved ferrous iron relative to dissolved sulfide. High concentrations of authigenic remanence‐bearing iron sulfides, including greigite and hexagonal 3C pyrrhotite, which can be detected using remanence parameters but not in‐field concentration dependent parameters, accumulate in a transient horizon at the base of the SMT during this early diagenesis, where sulfide is present but limited relative to dissolved ferrous iron. Formation of this remanence‐bearing iron sulfide horizon is likely facilitated by continued iron reduction through the SMT. Nonsteady state perturbations that shift the porewater profile, such as changes in carbon flux or sedimentation rate, can lead to preservation of these transient horizons, much like well documented preservation of manganese oxide layers in marine sediments following similar shifts to porewater profiles.

中文翻译：

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非稳态成岩作用引起的自生亚铁磁性硫化铁的保存：从西北韦德海的恒久漂移看

我们通过持久性漂移（高累积速率全新世生物硅质南极海洋沉积物）的浅层硫酸盐甲烷转换（SMT），记录了具有高分辨率磁化率，磁滞，等温剩余磁化强度和其他岩石磁性测量结果的磁性矿物成岩作用。SMT的结构由同一岩心的孔隙水测量值确定，可以直接进行比较。上部SMT发生碎屑（钛铁矿）磁铁矿组合的溶解，其中化学计量磁铁矿优先溶解。矫顽力较高的磁性矿物质溶解较慢，在整个SMT中继续溶解，并且可能是孔隙硫酸盐耗尽后微生物呼吸所需的三价铁来源，这是由于SMT下方的孔隙水亚铁的积累所提示。超顺磁性亚铁磁性矿物的富集/贫化通过SMT发生在三个阶段，并且与溶解的亚铁相对于溶解的硫化物的可用性紧密相关。在早期成岩过程中，可以使用剩磁参数而非场内浓度依赖性参数检测到高浓度的自生残渣含铁硫化物，包括钙铁矿和六角形3C黄铁矿，这些杂质会在SMT底部的瞬变层中积累，其中存在硫化物，但相对于溶解的亚铁而言是有限的。通过SMT不断还原铁，可能有助于形成这种剩磁的硫化铁层。改变孔隙水分布的非稳态扰动，例如碳通量或沉降速率的变化，