Much of the “new” Archean crust formed throughout this period made up a really unique association of three types of granitoid rocks– tonalite, granodiorite, and trondhjemite (TTG). Earlier researchers focused on the trace element composition of these rocks, hoping to find hints about TTG lavas and their source.Breakthrough in TTG Research” We tracked a particular set of trace elements that arent affected by change and pristinely preserve signatures from the original magma that made brand-new TTG crust,” said Dr. Matthijs Smit, associate professor and Canada Research Chair at the University of British Columbias (UBC) Department of Earth, Ocean and Atmospheric Sciences. “Ours is an easy model in which TTGs, as well as the more youthful rocks that TTGs are generally associated with, resulted from the slow burial, thickening and melting of precursor crust that most likely resembled oceanic plateaus.” Dispelling Old TheoriesThe UBC researchers discovery of a stand-alone “intra-crustal” system to make TTGs dispels the long-standing theory that Archean TTGs are formed in Earths first subduction zones and mark the start of plate tectonics.
Earlier scientists focused on the trace component composition of these rocks, hoping to find hints about TTG lavas and their source.Breakthrough in TTG Research” We tracked a particular set of trace components that arent affected by alteration and pristinely protect signatures from the initial magma that made new TTG crust,” said Dr. Matthijs Smit, associate professor and Canada Research Chair at the University of British Columbias (UBC) Department of Earth, Ocean and Atmospheric Sciences. “Ours is a basic design in which TTGs, as well as the more youthful rocks that TTGs are typically associated with, resulted from the sluggish burial, thickening and melting of precursor crust that most likely resembled oceanic plateaus.” Dispelling Old TheoriesThe UBC researchers discovery of a stand-alone “intra-crustal” mechanism to make TTGs eliminates the long-standing theory that Archean TTGs are formed in Earths first subduction zones and mark the start of plate tectonics.
