Quantifying Permanent Uplift Due To Lithosphere‐Hotspot Interaction. Issue 12 (24th December 2022)

• Record Type: Journal Article
• Authors: Lang, Guy; ten Brink, Uri S.
• Is Part Of: Tectonics. Volume 41:Issue 12(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-24
• Subjects: hotspot‐lithosphere interaction -- eastern North American margin -- Great Meteor Hotspot -- flexural isostasy -- permanent uplift -- mantle alteration; Geology, Structural -- Periodicals; 551.8
• DOI: 10.1029/2022TC007448
• Languages: English
• ISSNs: 0278-7407

Abstract

Abstract: Vertical motions that accompany the passage of the lithosphere over a mantle hotspot can shed light on the nature of the hotspot and its effect on the lithosphere. However, quantifying the temporal vertical and spatial extent, is challenging due to the paucity of evidence in the geological record. Here, we utilize dense seismic and well data covering the intersection of the Great Meteor Hotspot (GMH) track with the U.S. Atlantic continental margin to constrain the surface expression of the hotspot passage under the lithosphere. The continuous sedimentary record of the eastern North American margin during its passage over the hotspot allows determination of the timing, magnitude, width and rate of denudation. We find that a ∼300 km wide region was denuded by up to 850 m between ∼97 and 86 Ma, ∼10 m.y. after the passage of the GMH. Stratigraphic relationships suggest a decaying rock uplift rate with time and no subsequent sagging. The broad, long‐lasting, and delayed uplift was modeled as a surface manifestation of either sub‐lithospheric mantle depletion, permanently eroded base of the continental lithosphere, or intrusions of depleted magma. We consider sub‐lithospheric depletion to be the most likely cause, based on seismic imaging results. Key Points: A continental lithosphere surface response to its passage over a hotspot is quantified via stratigraphic analysis of a passive margin Ten m.y. after its passage over the Great Meteor Hotspot, the Georges Bank Basin was denuded by up to 850 m across a 300 km wide zone Asthenosphere depletion, lithospheric thinning or intrusion of depleted material triggered uplift and the consequent denudation