Global Geochemical Fingerprinting Points to a Mantle Dynamics Coupled
with the Supercontinent Cycle
Abstract
Plate tectonics and mantle plumes are two of the most fundamental
solid-Earth processes that operated through much of the Earth’s history.
For the past 300 million years, mantle plumes are known to derive mostly
from two large low shear velocity provinces (LLSVPs) above the
core-mantle boundary, referred to as the African and Pacific
superplumes. Whether such LLSVPs and their plume products are stationary
through Earth history, or dynamically linked to global plates motions
and subduction geometry, remains a first-order question for the
geoscience community. Here, we demonstrate that transition elements (Ni,
Cr and Fe/Mn) in basaltic rocks can be used as a tool to trace
plume-related magmatism through Earth history. An analysis of the global
petro-chemical database indicates the presence of a direct relationship
between the intensity of plume magmatism and the supercontinent cycle.
Such results favour the presence of a dynamic supercontinent-superplume
coupling over the fixed-LLSVP geodynamic model. In addition, our
analysis shows a consistent sudden drop in MgO, Ni and Cr at
~3.2–3.0 billion years ago, possibly indicating an
abrupt change in mantle temperature at the start of global plate
tectonics.