LATE ARCHEAN SHELF-TO-BASIN IRON SHUTTLE CONTRIBUTES TO THE FORMATION OF THE WORLD-CLASS DATAIGOU BANDED IRON FORMATION

• DOI: 10.5382/econgeo.5047
• Publication Date: 2024-02-26T16:15:36Z
• Authors: Changle Wang; Mingguo Zhai; Leslie J. Robbins; Zidong Peng; Xin Zhang; Lianchang Zhang
• Keywords: World class; Banded iron formation

Abstract Banded iron formations (BIFs) are among the few chemical sedimentary archives that capture biogeo-chemical evolution of Fe cycling and redox early Earth. Although biologically recycled continental has been previously proposed to be a significant source in BIFs deposited from stratified ocean at onset Great Oxidation Event (GOE; ~2.5–2.2 Ga), constraining sources pathways Archean remains challenging. Here we present major trace element Fe-Nd-Cr isotope data for largest BIF (i.e., Dataigou) China test whether benthic shuttle was operative during deposition pre-GOE BIFs. The absence true, shale-normalized Ce anomalies, coupled with unfractionated Cr positive compositions, suggests occurred an anoxic water column under reducing atmospheric conditions, whereas Eu anomalies indicate input high-temperature hydrothermal source. Based on correlation between initial Nd data, suggest two were periodically mixed resulted Dataigou BIF. Here, following sources: (1) fluids sea-floor systems (low εNd(t) high δ56Fe), derived interaction underlying, older crust, (2) flux (high low generated by microbial Fe(III) reduction coastal sediments weathering nearby depleted landmass. Results presented here confirm, first time, microbially driven operational supplied basin-wide scale oxygen.