Phanerozoic/Cambrian period

Kenneth Sobieski This page is under construction

General

Adam Sedgwick (1758-1873)

The Cambrian Period, named for a sparsly fossiliferous sequence of rocks in Wales(Latin name: Cambria) occurred between 542 Million Years Ago (MYA) and 488 MYA. The system was named by Adam Sedgwick, a Geology professor at Cambridge University, in the 1830s.

Climate

The Cambrian world was bracketed between two ice ages, one during the late Late Proterozoic and the other during the Ordovician. During these ice ages, the decrease in global temperature led to mass extinctions. Cooler conditions eliminated many warm water species, and glaciation lowered global sea level. However, during the Cambrian there was no significant ice formation. None of the continents were located at the poles, and so land temperatures remained mild. In fact, global climate was probably warmer and more unifrom than it is today. With the beginning of the Cambrian at the retreat of Proterozoic ice, the sea level rose significantly. Lowland areas such as Baltica were flooded and much of the world was covered by epeiric seas. This event opened up new habitats where marine invertebrates, such as the trilobites, radiated and flourished.

Land Mass Configuration

Breakup of Rodinia into:

• Gondwana (today's southern continents)
• Laurentia (most of North America)
• Siberia
• Baltica

Intra-Cambrian Periods

Russian-Kazakhian Stages

• Batyrbayan (491.5 - 488)
• Aksayan (493 - 491.5)
• Sakian (494.5 - 493)
• Ayusokkanian (501 - 494.5)
• Mayan (502-501)
• Amgan (513 - 502)
• Toyonian (518.5 - 513)
• Botomian (524 - 518.5)
• Atdabanian (530 - 524)
• Tommotian (534 - 530)
• Nemakit-Daldynian (542 - 534)

Regional Stages

• Dolgellian (492.5 - 488)
• Festiniogian (496.8 - 492.5)
• Maentwrogian (501 - 496.8)
• Lenian (524 - 513)

North American Stages

• Sunwaptan (493MYA To 491MYA)
• Steptoan (494.5MYA To 493MYA)
• Marjuman (504 To 494.5 Ma)
• Delamaran (512MYA To 504MYA)
• Dyeran (524.5MYA To 512MYA)
• Montezuman (529.5MYA To 524.5MYA)

Australian Stages

• Payntonian (491 - 488)
• Idamean (497 - 494)
• Mindyallan (501-497)
• Boomerangian (504-501)
• Undillian (506-504)
• Florian (508-506)
• Templetonian (510-508)
• Ordian (520 - 510)

Chinese Stages

• Zhungxian (505 - 501)
• Zuzhuangian (509-505)
• Maozhangian (513 - 509)
• Longwangmioan (518-513)
• Changlangpuan (523-518)
• Qungzusian (532 - 523)
• Meishuchuan (542 +/- 0.3 To 532 Ma)

	MYA	Russian-Kazakhian Stage	Regional Stage	North American Stage	Australian Stage	Chinese Stage
LATE CAMBRIAN (501MYA - 488MYA)	488	Batyrbayan (491.5 - 488)	Dolgellian (492.5 - 488)		Payntonian (491 - 488.3)
	488.5
	489
	489.5
	490
	490.5
	491			Sunwaptan (493MYA To 491MYA)
	491.5
	492	Aksayan (493 - 491.5)
	492.5
	493	Sakian (494.5 - 493)	Festiniogian (496.8 - 492.5)
	493.5			Steptoan (494.5MYA To 493MYA)
	494				Idamean (497 - 494)
	494.5	Ayusokkanian (501 - 494.5)
	495			Marjuman (504 To 494.5 Ma)
	495.5
	496
	496.5
	497
	497.5		Maentwrogian (501 - 496.8)		Mindyallan (501-497)
	498
	498.5
	499
	499.5
	500
	500.5
	501	Mayan (502-501)				Zhungxian (505 - 501)
MIDDLE CAMBRIAN (513MYA - 501MYA)	501.5				Boomerangian (504-501)
	502	Amgan (513 - 502)
	502.5
	503
	503.5
	504
	504.5			Delamaran (512MYA To 504MYA)	Undillian (506-504)
	505
	505.5					Zuzhuangian (509-505)
	506
	506.5				Florian (508-506)
	507
	507.5
	508
	508.5				Templetonian (510-508)
	509					Maozhangian (513 - 509)
	509.5
	510				Ordian (520 - 510)
	510.5
	511
	511.5
	512
	512.5			Dyeran (524.5MYA To 512MYA)
	513		Lenian (524 - 513)
	513.5	Toyonian (518.5 - 513)				Longwangmioan (518-513)
EARLY CAMBRIAN (542MYA - 513MYA)	514
	514.5
	515
	515.5
	516
	516.5
	517
	517.5
	518
	518.5	Botomian (524 - 518.5)				Changlangpuan (523-518)
	519
	519.5
	520
	520.5
	521
	521.5
	522
	522.5
	523					Qungzusian (532 - 523)
	523.5
	524
	524.5	Atdabanian (530 - 524)
	525			Montezuman (529.5MYA To 524.5MYA)
	525.5
	526
	526.5
	527
	527.5
	528
	528.5
	529
	529.5
	530
	530.5	Tommotian (534 - 530)
	531
	531.5
	532			v
	532.5					Meishuchuan (542 +/- 0.3 To 532 Ma)
	533
	533.5
	534
	534.5	Nemakit-Daldynian (542 - 534)
	535
	535.5
	536
	536.5
	537
	537.5
	538
	538.5
	539
	539.5
	540
	540.5
	541
	541.5
	542

Stratigraphy

On of the most famous stratigraphic formations is the Burgess Shale in what is now British Columbia's Yoho National Park, in an area of the Canadian Rocky Mountains known as the Burgess Pass.

Flora and Fauna: The Cambrian Explosion

With the breakup of Rodinia, and the melting of glaciers, the world gained much more warm, shallow, oxygen-rich coastlines which life could exploit. The favorable climate lead to what is popularly known as "The Cambrian Explosion." The Cambrian Explosion seems, in fact, to have been an "arms race" between the predators and the prey, which may also help to explain the diversity.

Land Animals

• NONE

Sea Animals

• Invertibrates
  • Aysheaia pedunculata
  • Hallucigenia
  • Anomalocaris
  • Opabinia
  • Wiwaxia
  • Arthropods
    • trilobites
      • most abundant and diverse animals of Cambrian time
      • long antennae, compound eyes, many jointed legs, and a hard exoskeleton
      • ranged from a few millimeters (1 mm = 0.25 inches) to 45 centimeters (18 inches).
  • archaeocyathids
  • hyoliths
  • monoplacophorans
  • inarticulate brachiopods
  • primitive echinoderms
  • articulate brachiopods
  • stony and lacy bryozoans
  • stromatoporoids
  • cephalopods
  • crinoids and blastoids
  • starfish
  • graptolites
  • bivalves
  • gastropods
  • vertebrates
  • echinoids
  • crustaceans
  • gymnolaemate bryozoans

• Vertibrates
  • Haikouichthys

Land Plants

• NONE

Sea Plants

• Single-Celled
  • Algaes
  • Fungi (molds, mushrooms, and yeasts)
  • lichens (cooperation between fungi and algae to form a single-organism partnership)
  • mosses

• Multi-Celled
  • None