THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)

Grenville Province Orogenic Belt (0.9-1.3 byBP)

Contains metamorphosed sedimentary rocks, igneous intrusions

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)

Grenville Province Orogenic Belt (0.9-1.3 byBP)

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THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)

Grenville Province Orogenic Belt (0.9-1.3 byBP)

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)

Grenville Province Orogenic Belt (0.9-1.3 byBP)

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)

Mesoproterozoic RocksIgneous Rocks

Anorogenic igneous intrusions (those not associated with orogenic or mountain-building events) occurred from 1.4-1.5 by in a broad belt across North America, from California to Labrador.

The plutons are composed primarily of anorthosites (rocks dominated by calcium-rich plagioclase feldspar and gabbroic minerals) and granites.

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)

Mesoproterozoic RocksBelt Supergroup

Going to the Sun MountainGlacier National Park

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)

Mesoproterozoic RocksBelt Supergroup

Chief MountainGlacier National Park

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)

Mesoproterozoic RocksBelt Supergroup

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)

Mesoproterozoic RocksGrand Canyon Sequence

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)

Mesoproterozoic RocksGrand Canyon Sequence

Vishnu SchistZoroaster Granite

The gorge is black and narrow below, red and gray and flaring above, with crags on the walls. Down in these grand, gloomy depths we glide, ever listening, for the mad waters keep up their roar. The boats are entirely unmanageable. - John Wesley Powell

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)Mesoproterozoic RocksGrand Canyon Sequence

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)Mesoproterozoic RocksGrand Canyon Sequence

Part of Mazatal Orogeny

(1.6-1.8 byBP)

THE LESS-PRIMORDIAL EARTHThe Mesoproterozoic Era (1.0-1.6 byBP)Mesoproterozoic RocksGrand Canyon Sequence (correlative with Belt)

THE LESS-PRIMORDIAL EARTHThe Neoproterozoic Era (0.544 - 1.0 byBP)Neoproterozoic RocksGrand Canyon Sequence

THE LESS-PRIMORDIAL EARTHThe Fossil RecordEucaryotes

Appeared by Mesoproterozoic time (1.6 by to 1.4 byBP).

Increased in abundance about 1.4 by ago.

Potential for sexual reproduction and increasing variation.

THE LESS-PRIMORDIAL EARTHThe Fossil RecordAcritarchs

Single-celled spherical, organic-walled microfossils. It is not known what sort of organism they were. They may have been phytoplankton. First appeared 1.6 by ago. Maximum diversity and abundance 850 my ago. They declined steadily during the Neoproterozoic

glaciation. Few remained by 675 my ago. Useful for correlation in Proterozoic strata.

EARLY PALEOZOIC EVENTS

Beginning of PHANEROZOIC EONtranslates “visible life”

EARLY PALEOZOIC EVENTS

Beginning of Phanerozoicis also beginning of thePALEOZOIC ERA

translates “ancient life”

EARLY PALEOZOIC EVENTSPALEOGEOGRAPHY