paleoproterozoic

Continents existed in the Paleoproterozoic, but we know little about them.

Perhaps the rise of free oxygen that occurred during this part of the Paleoproterozoic removed methane in the atmosphere through oxidation.

"Paleomagnetic Evidences for the Evolution of the Earth during Early Paleoproterozoic."

The Paleoproterozoic (about 2.5 to 2.0 Ga) was the source of orogenetic belts and the current configuration of the craton.

(2005) "Late Archean to Early Paleoproterozoic global tectonics, environmental change and the rise of atmospheric oxygen."

The only extensive iron formations that were deposited after the Paleoproterozoic (after 1.8 billion years ago) are associated with Cryogenian glacial deposits.

In the Paleoproterozoic the sulfate in seawater had increased to an amount greater than in the Archean, but was still lower than present day values.

In Dalarna the basement rocks consist of granites dated as 1.6 billion years old, putting them at the boundary between the Paleoproterozoic and the Mesoproterozoic.

It is subdivided into three geologic eras (from oldest to youngest): the Paleoproterozoic, Mesoproterozoic, and Neoproterozoic.

The Proterozoic eon is divided into three eras: the Neoproterozoic, Mesoproterozoic and Paleoproterozoic.

The archean rocks members of Belo Horizonte complex and supracrustal sequences of the Paleoproterozoic is predominant.

The ore is magnetite-bearing iron formation of the Paleoproterozoic Biwabik Iron Formation.

This area was originally formed when cratons collided and welded together 1.8-1.9 billion years ago in the Trans-Hudson orogeny during the Paleoproterozoic Era.

The age of the local granite bedrock of the Central Finland Granite Complex is 1.88 Ga (Paleoproterozoic).

Garnet-bearing harzburgite is found as a xenolith in some kimberlite pipes, which are found almost exclusively in ancient continental cratons of Archean or Paleoproterozoic age.

The central part of the zone lacks Archean rock, however, leading at least one group of scientists to speculate that it was formed very late in the Paleoproterozoic Era.

The basin contains thick (locally up to 12 km) marine and non-marine sedimentary rocks which were deposited from the late Paleoproterozoic to the early Mesoproterozoic (1800-1430 Ma).

Along the east margin of the craton collision with the Paleoproterozoic Trans-Hudson orogen intensely deformed Archean cratonic rocks in the Hartville uplift.

At 1.8 Ga, Banded iron formations (BIF) are common sedimentary rocks throughout the Archean and Paleoproterozoic; their disappearance marks a distinct shift in the chemistry of ocean water.

It was formed about 1,810 million years ago as a result of continental arc volcanism when the Archean Slave craton started to collide with the Paleoproterozoic Hottah terrane to the west.

Parallel to the Paleoproterozoic Hurwitz Group are massive veins of green biotite that are interpreted to have been emplaced there by a hydrothermal event accompanying a deformation along this contact area.

The Trans-Hudson orogeny was the culminating event of the Paleoproterozoic Laurentian assembly, which occurred after the Wopmay orogeny (West of Hudson Bay, ca. 2.1-1.9 Ga.).

Lower parts of the crust in the western Glennie Domain may be portions of the Sask craton that are significantly more complicated and comprise interleaved Archean and Paleoproterozoic rocks.

They unconformibly overlie the Archean to Paleoproterozoic formations which make up the basement rock in the area, and they lie unconformibly below the meso-Neoproterozoic sedimentary rocks, which include sandstones and limestones.

The Kisseynew back-arc basin (Kisseynew domain) is a metasedimentary gneiss belt that is one of the most extensive tectonic segments of the Paleoproterozoic Trans-Hudson orogen in north-central Canada.