Glacial cycles drive variations in the production of oceanic crust

Abstract

Glacial cycles redistribute water between oceans and continents, causing pressure changes in the upper mantle, with consequences for the melting of Earth's interior. Using Plio-Pleistocene sea-level variations as a forcing function, theoretical models of mid-ocean ridge dynamics that include melt transport predict temporal variations in crustal thickness of hundreds of meters. New bathymetry from the Australian-Antarctic ridge shows statistically significant spectral energy near the Milankovitch periods of 23, 41, and 100 thousand years, which is consistent with model predictions. These results suggest that abyssal hills, one of the most common bathymetric features on Earth, record the magmatic response to changes in sea level. The models and data support a link between glacial cycles at the surface and mantle melting at depth, recorded in the bathymetric fabric of the sea floor.

Glacial Isostatic Adjustment modelling: historical perspectives, recent advances, and future directions

“…This can be deduced from records of hydrothermal and magmatic activity along mid-ocean ridges (Crowley et al, 2015;Lund et al, 2016), while models of melt transport through the mantle predict a lag of at least 60 kyr between a fall in sea-level and an increase in CO 2 emissions (Burley and Katz, 2015). The magnitude of the lag depends on a number of factors, including the plate spreading rate and the rate of sea-level change, so it is not a simple task to quantify the time-dependent net effect of terrestrial and marine volcanic processes on atmospheric CO 2 .…”

Postglacial eruptive history of the Askja region, North Iceland

“…An expected corollary of subaerial deglaciation is decreased magmatic productivity at ocean ridges due to the additional loading associated with rising sea levels. There is considerable interest in the feedbacks between subaerial and submarine CO 2 emissions and glacial cycles: recent papers have proposed that pulsing of ocean ridge magma productivity, and hence CO 2 emissions, may feed back into climate cycles and possibly contribute to the abrupt ending of ice ages on a 100-kyr timescale (Burley and Katz 2015;Crowley et al 2015;Olive et al 2015;Tolstoy 2015).…”

Earth's Obliquity Oscillations Can Influence Climate Change by Driving Global Volcanic Activity

“…Until recently, the geodynamic factor was not taken into account in the Astronomical theory of longterm climate change [3,8]. There is another physical link (Solar system's gravitation) which can produce orbital-scale oscillations in the Earth's body.…”

“…The study of long-term geophysical and geochemical effects of seafloor magma extrusion and large volcanic eruptions must take into account the geodynamic response to oscillations in obliquity, which would lead to creation of more realistic numerical models of the past climate changes (see e.g. discussion in [7,8,10]). New results are in accordance with [7,11] and [10,19], but contradict to the suggestions of [8] and partly [13].…”

“…[3]). Geologic and climatic discoveries of the past few decades give impulse to exploring mechanisms that could translate orbital factors to changes in past climate [4][5][6][7][8][9][10]. Different climate proxy time series contain powerful 41-ky (1ky=1000 years) oscillation mode during the past 800 ky ( Fig.1 from [3], and earlier in the Plio-Pleistocene this mode predominated ( Fig.…”