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The Breakup of RodiniaContinental Rifting, during or after deposition of the Pahrump Group

North American Craton“Laurentia”Australia / Antarctica

The Ediacaran(eedee-auck-corrine)

~630 – 542 my

Named after the Ediacaria Hills

of South Australia

Worm Tubes in the Noonday Dolomite

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Puddingstone:A conglomerate with colorful clasts, often

metamorphosed or meta-conglomerate

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1.1 Billion Years BP 650 Mya

Proposed reconstruction of Rodinia for 750 Ma, with orogenic belts of 1.1 Ga age highlighted in green.[Red

dots indicate 1.3–1.5 Ga granites.

Intro To Paleozoic NA

Cambrian – Permian

Time?

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The Great Unconformity exposed in the Grand Canyon. The Vishnu Schist below is ~1.7by overlain by the Tapeats Sandstone ~530my

Western North America during early Paleozoic

Paleozoic Index Fossils

More later

North America

changes it’s

latitude and

orientation in the

last ~500 my

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Some Evidence???

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The Paleo-orientation of a Continent can be determined from the

Earth’s Magnetic Field

Paleo-latitudes

can be interpreted

from Magnetic

Inclination

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Polar Reversals

Normal Polarity Reverse Polarity

Polarity Periods are called “Chrons”

Chrons can last between ~10,000 –>1,000,000 years

Reversals take around 1,000 – 10,000 years

The Brunhes-Matuyama Reversal occurred 780,000 years ago.

Bernard Brunhes (1867–1910) was a French geophysicist known for his pioneering work in paleomagnetism; 1906 discovery of geomagnetic reversal.

Motonori Matuyama 1884 – 1958) was a Japanese geophysicist who was the first to surmise that the Earth's magnetic field had undergone reversals in the past.

p

Polar Reversals createMagnetic Anomalies on the seafloor, and invertical sectionsof continental crust.

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A Geomagnetic Excursion Back to this……..

Thinner to the east, thicker to the west

Geocline Geocline

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ATTRIBUTES OF GEOCLINESModified from P. B. King

• They from as a gradual process.

• They are NOT ordinary synclinal folds.

• They are sedimentary basins that form under tectonic control.

• Subsidence is not a necessary consequence of sedimentation, but an independent process. Sedimentation can cause more subsidence.

• They occur along the margins of Continents. There is much variation in tectonic setting:1. coastal interior, continental shelf, slope and rise2. deep sea trenches, island arcs, accretionary wedges and ocean floors

• Sediments of geoclines are varied. Some have shallow water near shore sediments and some have off shore deep water sediments.

• Sediments eventually get deformed, metamorphosed and plutonized.

Western North America during early Paleozoic

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Paleozoic Geocline in California and Western US:

Miogeocline:

Eugeocline:

Klamath Mnts(McCloud and Tethyan Fauna)

Paleozoic Rocks in other provinces:

Coast Range

Transverse Range

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End of the Paleozoic:

Mountain Building in WesternUS; Docking of Sonomia

Consolidation of Continents;Formation of Pangaea

Formation of Pangaea

(300 – 250 my )

Pangaea breaks up, formation of Atlantic

Ocean and a Passive Cont Margin

(~200my present)

End of the Paleozoic:

Mountain Building in WesternUS; Docking of Sonomia

Consolidation of Continents;Formation of Pangaea

Major Mass ExtinctionHistory of thought on causes:

Worldwide Regression,(1960s, ’70s, 10 – 20 millionYears) OR… faster……?

C-12 to C-13 ratios, WillistonLake British Columbia, 1994 (8 – ~100,00 thousand years?)

C-12 = 99%C-13 = ~1%C-14 = 1 part per trillion in atmosphere

Williston Lake, British Columbia

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End of the Paleozoic:

Mountain Building in WesternUS; Docking of Sonomia

Consolidation of Continents;Formation of Pangaea

Major Mass ExtinctionHistory of thought on causes:

Worldwide Regression,(1960s, ’70s, 10 – 20 millionYears) OR… faster……?

C-12 to C-13 ratios, WillistonLake British Columbia, 1994 (8 – ~100,00 thousand years?)

Volcanism in Siberia?

Impact Event? 1) Buckyballs with He-3, 20012) Bedout Crater, May 2004

Map of the Siberian TrapsOne of the largest known volcanic eruptions in the last 500 million years

Spans the Permo-Triassic ExtinctionAmount extruded :~1 – 4 million Km3, Covers: ~2 million Km2

May have originally covered as much as 7 million Km2

Lasts for millions of years

Siberian Traps are currently 4X the area of the current Colombia River Plateau. At one point, may have been > 10X the area

End of the Paleozoic:

Consolidation of Continents;Formation of Pangaea

Mountain Building in WesternUS; Docking of Sonomia

Major Mass ExtinctionHistory of thought on causes:

Worldwide Regression,(1960s, ’70s, 10 – 20 millionYears) OR… faster……?

C-12 to C-13 ratios, WillistonLake British Columbia, 1994 (8 – ~100,00 thousand years?)

Volcanism in Siberia?

Impact Event? 1) Buckyballs with He-3, 20012) Bedout Crater, May 2004

Bedout: A Possible End-Permian Impact Crater Offshore of Northwestern Australia

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Researcher Luann Becker holding a bottle containing fullerenes (left) extracted from sediment at 250 my Permo-Triassic Extinction sites from Japan,

China and Hungary

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End of the Paleozoic:

Consolidation of Continents;Formation of Pangaea

Mountain Building in WesternUS; Docking of Sonomia

Major Mass ExtinctionHistory of thought on causes:

Worldwide Regression,(1960s, ’70s, 10 – 20 millionYears) OR… faster……?

C-12 to C-13 ratios, WillistonLake British Columbia, 1994 (8 – ~100,00 thousand years?)

Volcanism in Siberia?

Impact Event? 1) Buckyballs with He-3, 20012) Bedout Crater, May 2004