Eruption, emplacement and internal architecture of massive and super‐massive inflated submarine basalt lava flows, Walvis Ridge hotspot track, IODP Expeditions 391/397T

Shervais, John W., Scholpp, Jesse L., Widdowson, Mike, Nelson, Wendy R., Potter, Katherine E., Homrighausen, Stephan, White, Drew, Buchs, David ORCID: https://orcid.org/0000-0001-8866-8125, Heaton, Daniel E., Avery, Aaron, Bhutani, Rajneesh, Duncan, Robert A., Class, Cornelia, Tshiningayamwe, Mbili, Kubota, Yusuke, Wang, Xiao‐Jun, Wu, Tao, Sager, William W., Hoernle, Kaj and Höfig, Tobias 2025. Eruption, emplacement and internal architecture of massive and super‐massive inflated submarine basalt lava flows, Walvis Ridge hotspot track, IODP Expeditions 391/397T. Geochemistry, Geophysics, Geosystems 26 (6) , e2024GC012145. 10.1029/2024gc012145

PDF - Published Version Download (52MB)

Abstract

Massive submarine basalt flows were sampled at five sites on the Tristan‐Gough‐Walvis hotspot track in the South Atlantic by International Oceanic Discovery Program Expeditions 391/397T, where the plume was interacting with a mid‐ocean ridge, a setting similar to that the of modern Iceland. High resolution XRF core scans document significant internal chemical variations with depth in these flows. Some of this reflects basal olivine accumulation. However, some examples have “scallop‐shaped” patterns that are interpreted to represent influxes of new magma during flow lobe inflation with successive lava injections focused toward the base of the flow unit. Olivine concentration in the deeper parts of the flow is interpreted to reflect top‐down tapping of a vertically zoned magma chamber, with the upper part of the chamber erupting first, and successive eruptive pulses tapping progressively deeper levels of the stratified chamber. The occurrence of massive submarine lava flows requires high eruptive fluxes relative to pillow lava formation. Propagation of these massive flows is favored by (a) high sea water confining pressures, which inhibit vesiculation and keep effective viscosity low and dissolved volatile content high, and (b) chill zones and thick viscoelastic crusts of quenched lava on the flow tops, which effectively insulate the flow interior from ambient temperatures. The formation of a thin film of super‐heated steam on the upper flow surface may similarly enhance the insulation. Evidence suggests that similar massive flows on the seafloor may extend many kilometers from their vents.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Schools > Earth and Environmental Sciences
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/4.0/
Publisher:	Wiley
ISSN:	1525-2027
Date of First Compliant Deposit:	9 June 2025
Date of Acceptance:	28 April 2025
Last Modified:	09 Jun 2025 14:15
URI:	https://orca.cardiff.ac.uk/id/eprint/178926

Actions (repository staff only)

Edit Item