Melt-induced buoyancy may explain the elevated rift-rapid sag paradox during breakup of continental plates.

Quirk, David G. and Rüpke, Lars H. (2018) Melt-induced buoyancy may explain the elevated rift-rapid sag paradox during breakup of continental plates. Open Access Scientific Reports, 8 . Art.Nr. 9985. DOI 10.1038/s41598-018-27981-2.

[thumbnail of s41598-018-27981-2.pdf]
Preview
Text
s41598-018-27981-2.pdf - Published Version
Available under License Creative Commons: Attribution 4.0.

Download (2MB) | Preview
[thumbnail of 41598_2018_27981_MOESM1_ESM.pdf]
Preview
Text
41598_2018_27981_MOESM1_ESM.pdf - Supplemental Material
Available under License Creative Commons: Attribution 4.0.

Download (2MB) | Preview
[thumbnail of 41598_2018_27981_MOESM5_ESM.ppt] Slideshow
41598_2018_27981_MOESM5_ESM.ppt - Supplemental Material
Available under License Creative Commons: Attribution 4.0.

Download (25MB)

Supplementary data:

Abstract

The division of the earth’s surface into continents and oceans is a consequence of plate tectonics but a geological paradox exists at continent-ocean boundaries. Continental plate is thicker and lighter than oceanic plate, floating higher on the mantle asthenosphere, but it can rift apart by thinning and heating to form new oceans. In theory, continental plate subsides in proportion to the amount it is thinned and subsequently by the rate it cools down. However, seismic and borehole data from continental margins like the Atlantic show that the upper surface of many plates remains close to sea-level during rifting, inconsistent with its thickness, and subsides after breakup more rapidly than cooling predicts. Here we use numerical models to investigate the origin and nature of this puzzling behaviour with data from the Kwanza Basin, offshore Angola. We explore an idea where the continental plate is made increasingly buoyant during rifting by melt produced and trapped in the asthenosphere. Using finite element simulation, we demonstrate that partially molten asthenosphere combined with other mantle processes can counteract the subsidence effect of thinning plate, keeping it elevated by 2-3 km until breakup. Rapid subsidence occurs after breakup when melt is lost to the embryonic ocean ridge.

Document Type: Article
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
Refereed: Yes
Open Access Journal?: Yes
Publisher: Nature Research
Related URLs:
Date Deposited: 09 Jul 2018 12:25
Last Modified: 19 Mar 2021 10:34
URI: https://oceanrep.geomar.de/id/eprint/43635

Actions (login required)

View Item View Item