The effect of early diagenetic processes on the quantification of fossil micrometeorite abundance and flux in the geological record
File(s)
Author(s)
Mattia, Isabelle
Genge, Matthew
Suttle, Martin
Type
Journal Article
Abstract
Fossil micrometeorites (MMs) recovered from lithified sedimentary rocks, particularly iron-rich (I-type) cosmic spherules (CSs) provide valuable insights into past dust-forming events. Their abundances, when combined with estimates of local sedimentation rates can be used to reconstruct the flux of extraterrestrial dust. However, their preservation in the geological record is highly susceptible to postdepositional diagenetic processes, complicating their quantification and past flux calculations. This study investigated lenticular calcitic concretions as potential sites of enhanced preservation of fossil MMs. A total of 17–18 I-types (but no silicate dominated spherules, S-types) were recovered from Cenomanian sediments within the Cretaceous Chalk Supergroup at Lulworth Cove, England. The I-types, identified by optical and SEM–EDX analyses, exhibited typical dendritic textures and varying degrees of alteration, including mottled surfaces and loss of Ni and Cr by leaching. Calcitic concretions yielded a comparable concentration of I-types to the surrounding hosting marl, but due to the added carbonate cementation during their growth, preservation per original sediment volume was shown to be enhanced (potentially by up to ~60%). Calcitic concretions can therefore act as microenvironments that enhance fossil MM preservation by limiting complete dissolution and loss of I-types. To constrain possible diagenetic effects on fossil MM quantification, future studies should compare cosmic dust yields across multiple sites exposing the same targeted sedimentary horizon.
Date Issued
2026-01-24
Date Acceptance
2026-01-15
Citation
Meteoritics and Planetary Science, 2026
ISSN
1086-9379
Publisher
Wiley
Journal / Book Title
Meteoritics and Planetary Science
Copyright Statement
© 2026 The Author(s). Meteoritics & Planetary Science published by Wiley Periodicals LLC on behalf of The Meteoritical Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
License URL
Identifier
10.1111/maps.70105
Publication Status
Published online
Date Publish Online
2026-01-24