The research allows insight into the first stages of plate tectonics and the start of stable
continental crust.
About 150 to 200 kilometres, 93 to 124 miles, beneath the surface, geologic formations called 'mantle keels' act as stabilisers for the
continental crust.
Scientists propose that several freak episodes of global glaciation scoured away miles of
continental crust, obliterating a billion years of geologic history in the process.
"The only known evolved rocks from the Hadean aeon are those in northwest Canada, which have chemical compositions clearly distinct from those that dominate ancient
continental crust worldwide, suggesting they were formed in a different way," research co-author professor Phil Bland said.
Pakistan is also blessed with the Makran offshore basin, which is an oceanic and
continental crust subduction zone with deep water trenches and volcanic activity.
A new study exploring the geologic history of Earth has revealed that our planet's
continental crust, or the relatively thick part of the crust which formed large land masses, came to be much earlier than previously thought.
Continental crust on the other hand is several dozens thicker.
1990; Vernon 1990), the rheology of host magmas and the tectonic environments of granitoid rocks, as well as on the interaction between the
continental crust and the mantle (Didier et al.
LAYERS OF EARTH Approximate depth Layer underground Composition
Continental crust: 0-30
Continental crust: Light kilometers (0-19 miles) rocks, like granite Crust Oceanic crust: 0-5 km Oceanic crust: Dense, (0-3 mi) heavy rocks, like basalt 5-750 km Mix of solid rock and Upper (3-470 mi) rising magma, or Mantle molten rock 750-2,900 km Solid rock containing Lower (470-1,800 mi) the elements oxygen Mantle and silicon 2 900-5.200 km Liquid iron and nickel Outer (1,800-3,200 mi) Core Inner 5,200-6,400 km Earth's heaviest Core (3,200- 4,000 mi) materials, like solid iron Peak Layer temperature Facts 870[degrees] Celsius The crust is the least dense (1,600[degrees] layer of Earth.
There are more geological sites suitable for DBD as the granite layer that is required can be found at appropriate depths under most of the
continental crust.