Onset of carbonate biomineralization drove global reorganization of
sedimentation and subsidence patterns
Abstract
Carbonate rocks on continental crust are one of Earth’s largest
reservoirs of CO2 and yet the controls on their volume through time are
poorly understood. Here we quantify temporal changes in preserved
continental carbonate rocks over the last billion years in both global
and North America-specific datasets within paleogeographic context. We
find the preserved area of continental carbonate rocks increases by
~175% across the Neoproterozoic-Phanerozoic boundary
ca. 539 million years ago, coincident with the rise of macroscopic,
multicellular life and the evolutionary innovation of carbonate
biomineralization in shallow water reefs. We demonstrate that crustal
loading from carbonate sediments on one tropical paleo-continent (North
America) contributes to an increase in continent-scale accommodation in
the early Phanerozoic, expanding shallow marine environments. We predict
this feedback between enhanced carbonate accumulation and subsidence was
an important component of the termination of the Great Unconformity.
These results are combined into a new conceptual model that links the
changes in preserved carbonate rock volumes to the evolutionary
innovation of carbonate biomineralization in a range of complex
organisms. Our model implies evolutionary controls on the carbonate rock
reservoir enhanced CO2 sequestration at the beginning of the
Phanerozoic, with consequences for Earth’s carbon cycle, climate and
habitability.