Influence of Magnetofossils on Paleointensity Estimations Inferred From Principal Component Analyses of First?Order Reversal Curve Diagrams for Sediments From the Western Equatorial Pacific

Relative abundance of magnetite originated from magnetotactic bacteria (magnetofossils) in sediments may influence relative paleointensity (RPI) estimations the geomagnetic field, as some studies reported an inverse correlation between RPI and ratio anhysteretic remanent magnetization susceptibility to saturation isothermal (kARM/SIRM), a proxy proportion biogenic terrigenous magnetic minerals well grain size. This study aims evaluate magnetofossils on more selectively using first-order reversal curve (FORC) diagrams. We studied three cores (KR0515-PC4, MD982187, MR1402-PC1) western equatorial Pacific, among which large differences exist average natural intensity normalized by ARM kARM/SIRM. Principal component analyses (PCAs) were applied FORC diagrams measured bulk specimens silicate-hosted inclusions extracted Core endmembers (EMs) revealed (EM1: inclusions, EM2: other terrigenous, EM3: biogenic). EM3 proportions vary widely cores. The decreases with increasing proportion, is probably caused higher acquisition efficiency due small magnetostatic interactions. correlates kARM/SIRM, confirms that kARM/SIRM represents components. MR1402-PC1 has highest its within-core variation small. From FORC-PCA solely this core, we infer configurations chains such bending collapse also estimations.