GEOLOGICAL HISTORY OF MORVAN

SUMMAY OF THE GEOLOGIC HISTORY OF THE MORVAN

Main steps of the geologic evolution during the Paleozoic Era

(Geologic times scale of the International Commision on Stratigraphy, 2004)

AGE

in millions years

PERIOD

GEOLOGICAL UNITS

OROGENIC PHASES

542,0-488,3 My

488,3-443,7 My

443,7 -416,0 My

416,0-397,5 My

CAMBRIAN

ORDOVICIAN

SILURIAN

EARLY DEVONIAN

Gneissic basement

VARISCAN OROGENY

Eo-Variscan

Medio-Variscan

Neo-Variscan

397,5-385,3 My

 

Stratigraphic break + erosion

Acadian

385,3-359,2 My

359,2-345,3 My

MIDDLE & LATE DEVONIAN

EARLY CARBONIFEROUS

Devonian volcano-sedimentary deposits

Tournaisian and Early Visean volcano-sedimentary deposits

Subalcaline granitic intrusions

 

345,3-335 My

 

Stratigraphic break + erosion

Intra-Visean

335-326,4 My

EARLY CARBONIFEROUS

Late Visean volcanism

 

325 My

 

Alumino-potassic granitic intrusions

 

325-305 My

LATE CARBONIFEROUS

Stratigraphic break + erosion for Namurian and Westphalian

Two-micas microgranites

Sudetic II

306,5-299 My

LATE CARBONIFEROUS

Stephanian volcanic and sedimentary basins

 

299-260,4 My

PERMIAN

Autunian and Saxonian volcanic and sedimentary basins

 

 

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