Tectonic burial
From Wikipedia, the free encyclopedia
Tectonic Burial is the deformation of rocks caused by extreme pressure over millions of years.[1] It often causes temperature evolutions and deep burials.[2] Tectonic burial is usually the result of continental collisions or subduction in a region.[3] An increase in burial depth leads to a weakened basin and basement but creates better preservation structure within the basement.[4]
Sedimentary burial
Sedimentary burial is more typical when thinking of burial processes. Sedimentary burial is the deposition of sediments on and area of interest such as a sedimentary basin, oceans, or other locations typically leading to Diagenesis.
Tectonic burial
Tectonic Burial specifically refers to burial of material on a area of interest as a result of tectonic processes such as a Thrust fault or other processes of crustal thickening. Tectonic burial is common in orogenic systems such as mountain belts or collisional zones. This is a critical part of the rock cycle and can lead to burial metamorphism and heating.
Evidence for tectonic burial
Radiometric dating
One way of identifying a tectonic burial event is through radiometric dating.[5] Burial events may be radiometric dated by looking at the cooling of the event and its impact on the minerals within the formation.[5]
Metamorphism
When rocks or sediments get buried they begin to increase in temperature and pressure as the mass above accumulates. Metamorphism occurs at temperatures greater than 200 °C and pressures greater than 300 MPa.[3] Burial metamorphism overlaps with diagenesis with an increase in pressure and temperature.[3] Sedimentary rocks buried at depths of a couple kilo meters will begin generating temperatures above 300 °C without differential stress.[3]
Thermochronology
Tectonic burial events can be distinguished by Thermochronology. During a tectonic burial event rocks increase in heat until they reach their Closure temperature . These closure temperatures are an indication of burial depth history and are used by thermochronogists in dating a tectonic burial event.
Vitrinite reflectance
Sediment deposition over a basin with organic material can create a primary component of coal, Vitrinite. High temperatures and pressures associated with Tectonic burial could produce vitrinite from woody organic material thus the presence of vitrinite may be a good indicator for a tectonic burial event.