Evidence of magnetite reduction and primary magnetization destruction during early diagenesis in sediments from Maldives Inner Sea

Author(s)

Igor Gustavo da Fonseca Carrasqueira ^[1] ; Luca Lanci ^[2] ; Luigi Jovane ^[3]

Affiliation

^[1] Universidade de São Paulo. Instituto Oceanográfico. Departamento de Oceanografia Física - Brasil

^[2] University of Urbino. Department of Pure and Applied Science - Itália

^[3] Universidade de São Paulo. Instituto Oceanográfico. Departamento de Oceanografia Física - Brasil

• Document type: Journal article
• Source: Ocean and Coastal Research; v. 72, 2024-03-29.

Abstract

ABSTRACT Magnetic experiments have provided insight into the preservation of magnetite in sediments of the Inner Sea of the Maldives during early diagenesis. In this study, we present high-resolution remanence data on the upper 15 meters of the sedimentary record and a detailed magnetic characterization of discrete samples from the top 5.5 meters of the International Ocean Discovery Program (IODP) Site U1471 record. Based on magnetic experiments, it can be concluded that magnetite is rapidly reduced, with a large decrease in natural remanent magnetization (NRM) related to destruction of primary NRM below the upper two meters of the sedimentary record. In thermomagnetic experiments, the appearance of a greigite signal at 3.06 meters below sea floor (mbsf) suggests that current diagenesis could imprint nearly 100 kry of error on the chronology based on magnetostratigraphy. Furthermore, based on X-ray fluorescence data, it can be concluded that magnetite reduction did not affect the Fe record. (AU)

• FAPESP's process: 16/24946-9 - Sea-level changes and Global Monsoon System: clues from marine cores in Brazil
• Grantee: Luigi Jovane
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants