Ocean resurge-induced impact melt dynamics on the peak-ring of the Chicxulub impact structure, Mexico

Schulte, F. M., Wittmann, A., Jung, S., Morgan, J. V., Gulick, S. P. S., Kring, D. A., Grieve, R. A. F., Osinski, G. R., Riller, U. and IODP-ICDP Expedition 364 Science Party, (2021) Ocean resurge-induced impact melt dynamics on the peak-ring of the Chicxulub impact structure, Mexico. International Journal of Earth Sciences, 110(7), pp. 2619-2636. (doi: 10.1007/s00531-021-02008-w)

Abstract

Core from Hole M0077 from IODP/ICDP Expedition 364 provides unprecedented evidence for the physical processes in effect during the interaction of impact melt with rock-debris-laden seawater, following a large meteorite impact into waters of the Yucatán shelf. Evidence for this interaction is based on petrographic, microstructural and chemical examination of the 46.37-m-thick impact melt rock sequence, which overlies shocked granitoid target rock of the peak ring of the Chicxulub impact structure. The melt rock sequence consists of two visually distinct phases, one is black and the other is green in colour. The black phase is aphanitic and trachyandesitic in composition and similar to melt rock from other sites within the impact structure. The green phase consists chiefly of clay minerals and sparitic calcite, which likely formed from a solidified water–rock debris mixture under hydrothermal conditions. We suggest that the layering and internal structure of the melt rock sequence resulted from a single process, i.e., violent contact of initially superheated silicate impact melt with the ocean resurge-induced water–rock mixture overriding the impact melt. Differences in density, temperature, viscosity, and velocity of this mixture and impact melt triggered Kelvin–Helmholtz and Rayleigh–Taylor instabilities at their phase boundary. As a consequence, shearing at the boundary perturbed and, thus, mingled both immiscible phases, and was accompanied by phreatomagmatic processes. These processes led to the brecciation at the top of the impact melt rock sequence. Quenching of this breccia by the seawater prevented reworking of the solidified breccia layers upon subsequent deposition of suevite. Solid-state deformation, notably in the uppermost brecciated impact melt rock layers, attests to long-term gravitational settling of the peak ring.

• Item Type: Articles
• Additional Information: Funding: Open Access funding enabled and organized by Projekt DEAL. This work was supported by the German Science Foundation (Grants Ri 916/16-1, 2) and the National Science Foundation (Grants OCE-1737351, OCE-1736826 and OCE-1737087).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Pickersgill, Dr Annemarie
• Authors: Schulte, F. M., Wittmann, A., Jung, S., Morgan, J. V., Gulick, S. P. S., Kring, D. A., Grieve, R. A. F., Osinski, G. R., Riller, U., and IODP-ICDP Expedition 364 Science Party,
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: International Journal of Earth Sciences
• Publisher: Springer
• ISSN: 1437-3254
• ISSN (Online): 1437-3262
• Published Online: 18 March 2021
• Copyright Holders: Copyright © The Author(s) 2021
• First Published: First published in International Journal of Earth Sciences 110(7): 2619-2636
• Publisher Policy: Reproduced under a Creative Commons License