Collenia

Collenia
Cut of Collenia undosa from the 2.11 billion year old iron band ore of the Biwabik Iron Formation in the USA. Image section: 4.2 × 3.3 cm.
Temporal occurrence
2400 to 325 million years
Locations
Europe ( Russia ) North America (USA: Arizona , Minnesota , Montana ) Africa ( Zaire , South Africa , Mauritania - Taoudenni Basin ) Asia ( China , Japan , India: Himachal Pradesh , Karnataka , Madhya Pradesh , Rajasthan , Uttar Pradesh ) Australia ( Western Australia )
Systematics
Classification : Creature Domain : Bacteria (bacteria) Department : Cyanobacteria (Cyanobacteria) Family : Cancellous stroma Subfamily : Stromatolithi Genre : Collenia
Scientific name
Collenia
Walcott , 1914

Collenia is a genus of fossil cyanobacteria that formed stromatolites .

description

Collenia (especially Collenia symmetrica Fenton & Fenton) developed columnar colonies 20 centimeters wide and up to 40 centimeters high, which resembled a flattened hemisphere, which dipped brusquely at its edge. The microorganisms involved were most likely oxygen- producing photosynthesis bacteria that built up convex, smooth to slightly wavy layers in the center of the stromatolite structure.

species

The following types are scientifically described:

• Collenia albertensis
• Collenia baikali (c) a (also Baikalia baicalica ) - Gangolihat dolomite ( Middle Riphäum ), Nagod lime ( Semri group , Vindhya super group ), Sirbu shale - around 650 million years BP ( Bhander group , Vindhya super group )
• Collenia clappii - Bargawan Limestone ( Semri Group), Kheinjua Formation - 1110 ± 60 million years BP (Middle Riphäum), Rohtas Limestone (Semri Group)
• Collenia columnaris (also Colonella columnaris ) - Bargawan lime, Gangolihat dolomite, Sirbu shale
• Collenia cylindrica
• Collenia frequens - Bhagwanpura lime ( Semri group )
• Collenia kussiensis - (also Kussiella kussiensis ) - Arangi formation (Semri group), Gangolihat dolomite, Kajrahat limestone - 1721 ± 90 million years BP, Tirohan limestone ( Semri group)
• Collenia multiflabella
• Collenia parva
• Collenia symmetrica - Gangolihat dolomite, Kajrahat lime, Nagod lime, Tirohan lime
• Collenia undosa - Biwabik Iron Formation

distribution

Collenia undosa from the Precambrian of the USA

The cyanobacteria genus Collenia was widespread in the Proterozoic , especially in the period 2.4 to 2.2 billion years BP ( Siderium and Rhyacium or Oxygenium and Jatulium ). Their distribution decreased sharply towards the end of the Precambrian.

ecology

Cloud (1942) and others had already pointed out that the algae-based stromatolites thrive in both fresh and saline shallow water. Logan, Rezak and Ginsburg are of the opinion that the Collenia-like LLH stromatolites ( English lateral linkage of hemispheroids ) typically arise from coherent mats and layers of sediment held together by algae. Your ecotope is a marine, intertidal environment with little swell that is located in bays that extend deep into the hinterland and can also be protected by bars .

In general, algae stromatolites are not good index fossils , but very good ecological indicators of the deposition environment ( facies indicators ).

Individual evidence

1. ^ Rich, Thomas HV, Fenton, Carroll Lane, Fenton, Mildred Adams, and Rich, Pat Vickers: The fossil book: a record of prehistoric life . Dover Publications, New York 1996, ISBN 0-486-29371-8 .
2. ^ Carroll Lane Fenton, Pat Vickers Rich, Mildred Adams Fenton, and Thomas HV Rich: The Fossil Book: A Record of Prehistoric Life .
3. ↑ Valdiya, KS: Stromatolites of the lesser Himalayas and Their correlation . In: 22nd International Geological Congress . Part II. New Delhi 1969, p. 15-36 .
4. ↑ Valdiya, KS: Occurrence of magnesite deposits and time controlled variations of stromatolites in the Shali series, District Mahasu HP In: Geological Society of India . tape 4 , 1967, p. 125-128 .
5. ^ Raja Rao, CS and Mahajan, VD: Note on the stromatolites and probable correlation of the Bhagwanpur Limestone, Chhitogarh district, Rajasthan . In: Current Science . tape 34 , 1965, pp. 82-83 .
6. ↑ ^{a b} Kumar, S .: Stromatolites from Vindhyan rocks of Son Valley - Maihar area, Districts Mirzapur (UP) and Satna (MP) . In: Journal of the Palaeontological Society of India . tape 19 , 1973, p. 24-27 .
7. ^ Cloud, PE, Jr .: Notes on stromato1ites . In: American Journal of Science . v. 240, 1942, pp. 363-379 .
8. ↑ Logan, BW, Rezak, R. and Ginsburg, RN: Classification and environmental significance of algal stromatolites . In: Journal of Geology . v.72n.1, 1964, p. 68-83 .
9. ^ Ginsburg, RN: Ancient analogues of recent stromatolites . In: International Geological Congress Proceedings . pt. 22, 1960, pp. 26-35 .

Web links

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