Could promontories have restricted sea-glacier penetration into marine embayments during Snowball Earth events?

Glacial flow of floating marine ice in ‘‘Snowball Earth’’

[1] Simulations of frigid Neoproterozoic climates have not considered the tendency of thick layers of floating marine ice to deform and spread laterally. We have constructed a simple model of the production and flow of marine ice on a planetary scale, and determined ice thickness and flow in two situations: when the ocean is globally icecovered (‘‘hard snowball’’) and when the tropical waters r...

Snowball Earth: A thin-ice solution with flowing sea glaciers

[1] The late Neoproterozoic era, 600–800 Myr ago, was marked by at least two intervals of widespread cold that left glacial deposits at low paleolatitudes. Both ‘‘Snowball’’ solutions with global ice cover and ‘‘Slushball’’ solutions with ice-free tropical oceans have been proposed to explain the paleomagnetic data. The Snowball model is best able to explain the auxiliary geological evidence, p...

Biologically induced initiation of Neoproterozoic snowball-Earth events.

The glaciations of the Neoproterozoic Era (1,000 to 542 MyBP) were preceded by dramatically light C isotopic excursions preserved in preglacial deposits. Standard explanations of these excursions involve remineralization of isotopically light organic matter and imply strong enhancement of atmospheric CO(2) greenhouse gas concentration, apparently inconsistent with the glaciations that followed....

A neoproterozoic snowball earth

Negative carbon isotope anomalies in carbonate rocks bracketing Neoproterozoic glacial deposits in Namibia, combined with estimates of thermal subsidence history, suggest that biological productivity in the surface ocean collapsed for millions of years. This collapse can be explained by a global glaciation (that is, a snowball Earth), which ended abruptly when subaerial volcanic outgassing rais...

Snowball Earth ocean chemistry driven by extensive ridge volcanism during