Page 61 - Petrophysics
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TABLE 2.1
SUBDIVISIONS OF THE THREE GEOLOGIC ERAS AND THE ESTIMATED TIMES
OF MAJOR EVENTS [SI
Subdivisions Based on Stratamime I Radiometric
Systems1 Dates (millions In Physical
Periods Epochs of years ago) Histow
Quaternary Recent or 0 Several glacial
Holocene ages
Pleistocene 2
Pliocene 6 Colorado River
begins
Miocene 22 Mountains and
Tertiary basins in Nevada
Oligocene 36 Yellowstone Park
volcanism
Eocene 58
Paleocene 63 Rocky
Mountains begin
Lower Mississippi
River begins
Cretaceous 145 Atlantic Ocean
begins
Jurassic 210 Appalachian
I Mountains
climax
Triassic 255
Permian n 280
Pennsylvanian h 320
(upper
Carboniferous)
Mississippian 360
(Lower
Carboniferous)
Devonian 415 Appalachian
Silurian 465 Mountains
Ordovician 520 begin
Cambrian 580
Precambrian (Mainly igneous and 1000
metamorphic rocks, no worldwide
subdivisions)
2000
3000 Oldest dated
rocks
.................................................
Birth of Planet Earth 4650
