Instructural geology, asuture is a joining along a majorfault zone, of separateterranes,tectonic units that have differentplate tectonic,metamorphic andpaleogeographic histories. The suture is often represented on the surface by anorogen or mountain range.[1]
In plate tectonics, sutures are the remains ofsubduction zones, and the terranes that are joined are interpreted as fragments of differentpalaeocontinents ortectonic plates.
Outcrops of sutures can vary in width from a few hundredmeters to a couple ofkilometers. They can be networks ofmyloniticshear zones orbrittle fault zones, but are usually both. Sutures are usually associated withigneousintrusions andtectoniclenses with varying kinds oflithologies fromplutonic rocks toophiolitic fragments.[2]
An example fromGreat Britain is theIapetus Suture which, though now concealed beneath younger rocks, has been determined bygeophysical means to run along a line roughly parallel with theAnglo-Scottish border and represents the joint between the former continent ofLaurentia to the north and the formermicro-continent ofAvalonia to the south.[3] Avalonia is in fact aplain which dips steeply northwestwards through the crust, underthrusting Laurentia.
When used inpaleontology,suture can also refer tofossil exoskeletons, as in the suture line, a division on atrilobite between the free cheek and the fixed cheek; this suture line allowed the trilobite to performecdysis (the shedding of its skin).
{{cite book}}: CS1 maint: location missing publisher (link)Heron, P., Pysklywec, R. & Stephenson, R. Lasting mantle scars lead to perennial plate tectonics. Nat Commun 7, 11834 (2016).https://doi.org/10.1038/ncomms11834
