Titanium isotopes constrain a magmatic transition at the Hadean-Archean boundary in the Acasta Gneiss Complex

Title	Titanium isotopes constrain a magmatic transition at the Hadean-Archean boundary in the Acasta Gneiss Complex
Authors	Sarah M. Aarons 1 , 2 , * , Jesse R. Reimink 3 , 4 , Nicolas D. Greber 5 , Andy W. Heard 1 , Zhe Zhang 1 , Nicolas Dauphas 1
Magazine	Science Advances
Date	12/09/2020
DOI	10.1126/sciadv.abc9959
Introduction	Plate subduction has a profound influence on Earth's surface and deep interior, yet the onset of this process remains debated due to limited early geological records. Our study reveals that the titanium isotopic composition of orthogneisses from the Acasta Gneiss Complex, which spans the transition from the Hadean to the Eoarchean, aligns with two distinct magmatic differentiation trends. Hadean tonalitic gneisses exhibit titanium isotopic signatures that correspond to modern tholeiitic magmas, indicative of differentiation in plume settings. In contrast, younger Eoarchean granitoid gneisses share isotopic traits with modern calc-alkaline magmas, typical of convergent arcs. These findings highlight a significant magmatic shift from tholeiitic to calc-alkaline styles between 4.02 and 3.75 billion years ago in the Slave craton.
Quote	Sarah M. Aarons, Jesse R. Reimink and Nicolas D. Greber et al. Titanium isotopes constrain a magmatic transition at the Hadean-Archean boundary in the Acasta Gneiss Complex. Science Advances. 2020. Vol. 6(50). DOI: 10.1126/sciadv.abc9959
Element	Titanium (Ti)
Topics	Structural Materials
Industry	Research & Laboratory