Historical Geology

Lecture 16

The Middle Paleozoic Era

Historical Geology

I Paleozoic TimelineII Middle Paleozoic Paleogeography, Climate, and Sea LevelIII Geologic Framework

A) Carbonate SedimentationB) Organic ReefsC) Evaporite BasinsD) Clastic Wedges

IV The Silurian PeriodA) Paleogeography and LithofaciesB) Appalachian (Southern) MarginC) The Continental InteriorD) Cordilleran (Northern) Margin

V The Devonian PeriodA) Paleogeography and LithofaciesB) Kaskaskia SequenceC) Appalachian (Southern) MarginD) Cordilleran (Northern) Margin

Outline

Historical GeologyThe Middle Paleozoic Era

Historical GeologyMiddle Paleozoic Era Paleogeography

Ron Blakeyhttp://jan.ucc.nau.edu/~rcb7

Historical GeologyMiddle Paleozoic Era Climate

AverageGlobal

Temperature

Early Devonian415 mya

Early Silurian440 mya

Historical GeologyMiddle Paleozoic Sea Level

Historical GeologyMiddle Paleozoic Era

Geologic Framework

•Carbonate Sedimentation

•Organic Reefs

•Evaporite Basins

•Clastic Wedges

Historical Geology

•Shallow "Carbonate Factory"

•Deep Ocean Calcareous Ooze (since Mesozoic)

Carbonate Factory

Currents supply nutrientsLight for photosynthesisWarm watersNormal salinityGreatest biological productivity <10m

Middle Paleozoic EraGeologic Framework - Carbonate Sedimentation

Times of high sea level generally allow the factories to be below thedepth of the wave base and circulation. This prevents erosion or mixing of the sediments due to normal energy wave abrasion to the carbonate factory and results in a time of high sediment accumulation.

Times of low sea level expose the carbonate factory to the zone of wave energy circulation and can even place the factory above the water level. This results in erosion and lithification of the carbonate sediments and can be seen in the sediment record.

Historical Geology

Growth Stages and Architectural Elements through Time

Middle Paleozoic EraGeologic Framework - Organic Reefs

Historical Geology

Windjana GorgeDevonian Australia

Middle Paleozoic EraGeologic Framework - Organic Reefs

rock saltNaCl

anhydriteCaSO4

rock gypsumCaSO4

. H2O

Middle Paleozoic EraGeologic Framework – Evaporite Basins

Historical Geology

Historical GeologyMiddle Paleozoic Era

Geologic Framework - Clastic Wedges

Historical GeologyMiddle Paleozoic Rocks of Laurentia

Historical GeologyThe Silurian Period

Ron Blakeyhttp://jan.ucc.nau.edu/~rcb7

Laurentia Baltica Gondwanaland

Siberia

AntlerArc

Siberia

Baltica

PanthallasicOcean

RheicOcean

Paleo-TethysOcean

Gondwanaland

Historical GeologySilurian Laurentia

Historical GeologySilurian Laurentia

•The Continental Interior Basins– Evaporite Deposition– Niagara Falls

•Cordilleran (Northern) Margin– Convergence and Subduction– Approach of Antler Terrane

•Appalachian (Southern) Margin– Convergence in Iapetus Ocean– Approach of Avalonia– Erosion of Taconic Highlands– Caledonian Orogeny

Ron Blakeyhttp://jan.ucc.nau.edu/~rcb7

Historical GeologySilurian LaurentiaPaleogeography and Lithofacies

Historical GeologySilurian LaurentiaAppalachian Margin

• Approach of Avalonia

• Erosion of Taconic Highlands

• Appalachian Basin Sedimentation

• Caledonian Orogeny

Historical GeologySilurian LaurentiaAppalachian Margin - Caledonian Orogeny

Historical GeologySilurian LaurentiaContinental Interior Basins

•Michigan Evaporite Basin

Historical GeologySilurian LaurentiaContinental Interior Basins

•Michigan Evaporite Basin

Historical GeologySilurian LaurentiaContinental Interior Basins

Historical GeologySilurian LaurentiaContinental Interior Basins - Niagara Falls

Historical GeologySilurian LaurentiaCordilleran Margin

Ron Blakeyhttp://jan.ucc.nau.edu/~rcb7

Historical GeologyThe Devonian Period

Laurasia

Gondwanaland

Siberia

AntlerArc

SiberiaPanthallasicOcean

Rheic Ocean

Proto-TethysOcean

Chinafragments

Gondwanaland

SiberiaSiberia

Laurasia

AntlerArc

PanthallasicOcean

Gondwanaland

Mongol Arc

Kazakh Arc

Laurasia

417417

412412

400400

391391

380380

370370

364364

354354

Ron Blakeyhttp://jan.ucc.nau.edu/~rcb7

Historical GeologyDevonian Laurentia

Kaskaskia Transgression

● Oriskany Sandstone

Appalachian (Southern) Margin

● Acadian Orogeny

● Catskill Clastic Wedge

Cordilleran (Northern) Margin

● Antler Orogeny

Franklin Margin

● Ellsmere Orogeny

Ron Blakeyhttp://jan.ucc.nau.edu/~rcb7

Historical GeologyDevonian LaurentiaPaleogeography and Lithofacies

Historical GeologyDevonian Laurentia

Kaskaskia Transgression

Historical GeologyDevonian Laurentia

Kaskaskia Transgression - Oriskany Sandstone

•initial transgressive deposit over unconformity

•very mature sandstone

Historical GeologyDevonian Laurentia

Appalachian Margin

•Acadian Orogeny

•Catskill Clastic Wedge

Historical GeologyDevonian Laurentia

Appalachian Margin - Acadian Orogeny

Ron Blakeyhttp://jan.ucc.nau.edu/~rcb7

Historical GeologyDevonian Laurentia

Acadian Orogeny - Old Red Continent

Historical GeologyDevonian Laurentia

Appalachian Margin – Catskill Clastic Wedge

Historical GeologyDevonian Laurentia

Appalachian Margin – Catskill Clastic Wedge

Historical GeologyDevonian LaurentiaCordilleran Margin

•Antler Orogeny

Ron Blakeyhttp://jan.ucc.nau.edu/~rcb7

Historical GeologyDevonian Laurentia

Cordilleran Margin – Antler Orogeny

Ron Blakeyhttp://jan.ucc.nau.edu/~rcb7