![](https://upload.wikimedia.org/wikipedia/commons/thumb/3/33/Panotiaggg.jpg/220px-Panotiaggg.jpg)
Pannotia (from Greek: pan-, "all", -nótos, "south"; meaning "all southern land"), also known as the Vendian supercontinent, Greater Gondwana, and the Pan-African supercontinent, was a relatively short-lived Neoproterozoic supercontinent that formed at the end of the Precambrian during the Pan-African orogeny (650–500 Ma), during the Cryogenian period and broke apart 560 Ma with the opening of the Iapetus Ocean, in the late Ediacaran and early Cambrian.[1] Pannotia formed when Laurentia was located adjacent to the two major South American cratons, Amazonia and Río de la Plata. The opening of the Iapetus Ocean separated Laurentia from Baltica, Amazonia, and Río de la Plata.[2] A 2022 paper argues that Pannotia never fully existed, reinterpreting the geochronological evidence: "the supposed landmass had begun to break up well before it was fully assembled".[3] However, the assembly of the next supercontinent Pangaea is well established.
Origin of concept
J. D. A. Piper was probably the first to propose a Proterozoic supercontinent preceding Pangaea, today known as Rodinia.[4][5] At that time he simply referred to it as "the Proterozoic super-continent",[6] but much later he named this "symmetrical crescent-shaped analogue of Pangaea" 'Palaeopangaea' and in 2000 he still insisted that there is neither a need nor any evidences for Rodinia or its daughter supercontinent Pannotia or a series of other proposed supercontinents since Archaean times.[7]
The existence of a late Proterozoic supercontinent, much different from Pangaea, was first proposed by McWilliams 1981 based on paleomagnetic data, and the break-up of this supercontinent around 625–550 Ma was documented by Bond, Nickeson & Kominz 1984.[8] The reconstruction of Bond et al. is virtually identical to that of Dalziel 1997 and others.[9]
Another term for the supercontinent that is thought to have existed at the end of Neoproterozoic time is "Greater Gondwanaland", suggested by Stern 1994. This term recognizes that the supercontinent of Gondwana, which formed at the end of the Neoproterozoic, was once part of the much larger Neoproterozoic supercontinent.[10]
Pannotia was named by Powell 1995,[11] based on the term "Pannotios" originally proposed by Stump 1987 for "the cycle of tectonic activity common to the Gondwana continents that resulted in the formation of the supercontinent."[12] Young 1995 proposed renaming the older Proterozoic supercontinent (now known as Rodinia) "Kanatia", the St. Lawrence Iroquoian word from which the name Canada is derived, while keeping the name Rodinia for the latter Neoproterozoic supercontinent (now known as Pannotia).[13] Powell, however, objected to this renaming and instead proposed Stump's term for the latter supercontinent.
![](https://upload.wikimedia.org/wikipedia/commons/thumb/9/95/Pannotia_-_2.png/250px-Pannotia_-_2.png)
Formation
![](https://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Pannotia.svg/220px-Pannotia.svg.png)
The formation of Pannotia began during the Pan-African orogeny when the Congo Craton was lodged between the northern and southern halves of the previous supercontinent Rodinia some 750 Ma. The peak in this mountain building event was around 640–610 Ma, but these continental collisions may have continued into the early Cambrian some 530 Ma. The formation of Pannotia was the result of Rodinia turning itself inside out.[15]
When Pannotia had formed, Africa was located at the centre surrounded by the rest of Gondwana: South America, Arabia, Madagascar, India, Antarctica, and Australia. Laurentia, which 'escaped' out of Rodinia, Baltica, and Siberia kept the relative positions they had in Rodinia. The Cathaysian and Cimmerian terranes (continental blocks of southern Asia) were located along the northern margins of east Gondwana. The Avalonian-Cadomian terranes (later to become central Europe, Britain, the North American east coast, and Yucatán) were located along the active northern margins of western Gondwana. This orogeny probably extended north into the Uralian margin of Baltica.[15]
Pannotia formed by subduction of exterior oceans (a mechanism called extroversion)[16] over a geoid low, whereas Pangaea formed by subduction of interior oceans (introversion) over a geoid high[17] perhaps caused by superplumes and slab avalanche events.[18] The oceanic crust subducted by Pannotia formed within the Mirovia superocean that surrounded Rodinia before its 830–750 Ma break-up and were accreted during the late Proterozoic orogenies that resulted from the assembly of Pannotia.[19]
One of the major of these orogenies was the collision between eastern and western Gondwana or the East African Orogeny.[20] The Trans-Saharan Belt in West Africa is the result of the collision between the East Saharan Shield and the West African Craton when 1200–710 Ma volcanic and arc-related rocks were accreted to the margin of this craton.[19] Between 600 and 500 Ma, two Brazilian interior orogens were highly deformed and metamorphosed between a series of colliding cratons: Amazonia, West Africa-São Luís, and São Francisco-Congo-Kasai. The material that accreted included, 950–850 Ma, mafic meta-igneous complexes and younger arc-related rocks.[19]
Break-up
View centred on the South Pole.
The break-up of Pannotia was accompanied by sea level rise, dramatic changes in climate and ocean water chemistry, and rapid metazoan diversification.[20] Bond, Nickeson & Kominz 1984 found Neoproterozoic passive margin sequences worldwide—the first indication of a Late Neoproterozoic supercontinent but also the traces of its demise.[21]
The Iapetus Ocean started to open while Pannotia was being assembled, 200 Ma after the break-up of Rodinia. This opening of the Iapetus and other Cambrian seas coincided with the first steps in the evolution of soft-bodied metazoans, and also made a myriad of habitats available for them; this led to the so-called Cambrian explosion, the rapid evolution of skeletalized metazoans.[22]
Trilobites originated in the Neoproterozoic and began to diversify before the break-up of Pannotia 600–550 Ma, as evidenced by their ubiquitous presence in the fossil record, and the lack of vicariance patterns in their lineage.[21]
See also
Notes
- ^ Scotese 2009, Reconstruction of Rodinia and Pannotia, p. 68
- ^ Unrug 1997, pp. 3–4, Fig. 3
- ^ Nance, R. Damian; Evans, David A.D.; Murphy, J. Brendan (2022). "Pannotia: To be or not to be?". Earth-Science Reviews. 232: 104128. doi:10.1016/j.earscirev.2022.104128.
- ^ Piper 1976
- ^ For a more detailed description of the concept(s) of the supercontinent cycle see: Nance, Murphy & Santosh 2014, Indications of pre-Pangean supercontinents, pp. 6, 8
- ^ Piper 1976, Geological and Geophysical implications, p. 478
- ^ Piper 2000, Abstract; Piper 2010, Abstract
- ^ Murphy & Nance 1991, Introduction, p. 469
- ^ Meert & Powell 2001, Fig. 1, p. 2
- ^ Stern 1994, Fig. 1, p. 321; fig. 5, p. 329
- ^ Powell 1995, p. 1053
- ^ Stump 1987, Abstract; Stump 1992, Pannotios tectonism, pp. 30–31
- ^ Young 1995, p. 154
- ^ Dalziel 1997, Fig. 12, p. 31
- ^ a b Scotese 2009, Reconstruction of Pannotia, pp. 71–72
- ^ Murphy & Nance 2013, Introduction, pp. 185–187
- ^ Murphy & Nance 2013, Discussion, p. 191
- ^ Murphy & Nance 2013, Conclusions, p. 192
- ^ a b c Murphy, Nance & Cawood 2009, Assembly of Pannotia, pp. 412–13
- ^ a b Murphy, Nance & Cawood 2009, Development of concepts, pp. 410–11
- ^ a b Meert & Lieberman 2004, Results, Discussion, pp. 4–5
- ^ Dalziel 1997, p. 38
References
- Bond, G. C.; Nickeson, P. A.; Kominz, M. A. (1984). "Breakup of a supercontinent between 625 Ma and 555 Ma: new evidence and implications for continental histories". Earth and Planetary Science Letters. 70 (2): 325–45. Bibcode:1984E&PSL..70..325B. doi:10.1016/0012-821X(84)90017-7.
- Dalziel, I. W. (1997). "Neoproterozoic-Paleozoic geography and tectonics: Review, hypothesis, environmental speculation". Geological Society of America Bulletin. 109 (1): 16–42. Bibcode:1997GSAB..109...16D. doi:10.1130/0016-7606(1997)109<0016:ONPGAT>2.3.CO;2.
- Goodge, J. W.; Vervoort, J. D.; Fanning, C. M.; Brecke, D. M.; Farmer, G. L.; Williams, I. S.; Myrow, P. M.; DePaolo, D. J. (2008). "A positive test of East Antarctica–Laurentia juxtaposition within the Rodinia supercontinent" (PDF). Science. 321 (5886): 235–40. Bibcode:2008Sci...321..235G. doi:10.1126/science.1159189. ISSN 0036-8075. PMID 18621666. S2CID 11799613. Retrieved 7 February 2016.
- McWilliams, M. O. (1981). "Palaeomagnetism and Precambrian tectonic evolution of Gondwana". In Kröner, A. (ed.). Precambrian Plate Tectonics. Developments in Precambrian Geology. Vol. 4. pp. 649–87. doi:10.1016/S0166-2635(08)70031-8. ISBN 9780080869032.
- Meert, J. G.; Lieberman, B. S. (2004). "A palaeomagnetic and palaeobiogeographical perspective on latest Neoproterozoic and early Cambrian tectonic events" (PDF). Journal of the Geological Society. 161 (3): 477–87. Bibcode:2004JGSoc.161..477M. doi:10.1144/0016-764903-107. hdl:1808/93. S2CID 5713392. Retrieved 16 January 2016.
- Meert, J. G.; Powell, C. M. (2001). "Assembly and break-up of Rodinia: introduction to the special volume" (PDF). Precambrian Research. 110 (1): 1–8. Bibcode:2001PreR..110....1M. doi:10.1016/s0301-9268(01)00177-2. Retrieved 6 December 2019.
- Meert, J. G.; Torsvik, T. H. (2003). "The making and unmaking of a supercontinent: Rodinia revisited". Tectonophysics. 375 (1): 261–88. Bibcode:2003Tectp.375..261M. doi:10.1016/S0040-1951(03)00342-1.
- Murphy, J. B.; Nance, R. D. (1991). "Supercontinent model for the contrasting character of Late Proterozoic orogenic belts". Geology. 19 (5): 469–72. Bibcode:1991Geo....19..469B. doi:10.1130/0091-7613(1991)019<0469:smftcc>2.3.co;2. Retrieved 6 December 2019.
- Murphy, J. B.; Nance, R. D. (2013). "Speculations on the mechanisms for the formation and breakup of supercontinents" (PDF). Geoscience Frontiers. 4 (2): 185–94. doi:10.1016/j.gsf.2012.07.005. Retrieved 13 December 2015.
- Murphy, J. B.; Nance, R. D.; Cawood, P. A. (2009). "Contrasting modes of supercontinent formation and the conundrum of Pangea". Gondwana Research. 15 (3): 408–20. Bibcode:2009GondR..15..408M. doi:10.1016/j.gr.2008.09.005. Retrieved 20 December 2019.
- Nance, R. D.; Murphy, J. B.; Santosh, M. (2014). "The supercontinent cycle: a retrospective essay". Gondwana Research. 25 (1): 4–29. Bibcode:2014GondR..25....4N. doi:10.1016/j.gr.2012.12.026. Retrieved 25 June 2015.
- Piper, J. D. A. (1976). "Palaeomagnetic Evidence for a Proterozoic Super-Continent". Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences. 280 (1298): 469–90. Bibcode:1976RSPTA.280..469P. doi:10.1098/rsta.1976.0007. JSTOR 74572. S2CID 119465623.
- Piper, J. D. A. (2000). "The Neoproterozoic Supercontinent: Rodinia or Palaeopangaea?". Earth and Planetary Science Letters. 176 (1): 131–46. Bibcode:2000E&PSL.176..131P. doi:10.1016/S0012-821X(99)00314-3. Retrieved 6 December 2015.
- Piper, J. D. A. (2010). "Protopangaea: Palaeomagnetic definition of Earth's oldest (mid-Archaean-Palaeoproterozoic) supercontinent". Journal of Geodynamics. 50 (3): 154–65. Bibcode:2010JGeo...50..154P. doi:10.1016/j.jog.2010.01.002. Retrieved 24 January 2016.
- Powell, C. McA. (1995). "Are Neoproterozoic glacial deposits preserved on the margins of Laurentia related to the fragmentation of two supercontinents? Comment". Geology. 23 (11): 1053–55. doi:10.1130/0091-7613(1995)023<1053:ANGDPO>2.3.CO;2.
- Scotese, C. R. (2009). "Late Proterozoic plate tectonics and palaeogeography: a tale of two supercontinents, Rodinia and Pannotia". Geological Society, London, Special Publications. 326 (1): 67–83. Bibcode:2009GSLSP.326...67S. doi:10.1144/SP326.4. S2CID 128845353. Retrieved 29 November 2015.
- Stern, R. J. (1994). "Arc-assembly and continental collision in the Neoproterozoic African orogen: implications for the consolidation of Gondwanaland" (PDF). Annual Review of Earth and Planetary Sciences. 22: 319–51. Bibcode:1994AREPS..22..319S. doi:10.1146/annurev.ea.22.050194.001535. Retrieved 3 December 2015.
- Stump, E. (1987). "Construction of the Pacific margin of Gondwana during the Pannotios cycle". In McKenzie, G. D. (ed.). Gondwana Six: Structure, tectonics and geophysics. American Geophysical Union Monograph. Vol. 40. pp. 77–87. Bibcode:1987GMS....40...77S. doi:10.1029/GM040p0077. ISBN 9781118664483.
- Stump, E. (1992). "The Ross orogen of the Transantarctic Mountains in the light of the Laurentian–Gondwana split" (PDF). GSA Today. 2: 25–27, 30–33. Retrieved 29 December 2015.
- Unrug, R. (1997). "Rodinia to Gondwana: the geodynamic map of Gondwana supercontinent assembly" (PDF). GSA Today. 7 (1): 1–6. Archived from the original (PDF) on 2018-06-01. Retrieved 13 December 2015.
- Young, G. M. (1995). "Are Neoproterozoic glacial deposits preserved on the margins of Laurentia related to the fragmentation of two supercontinents?" (PDF). Geology. 23 (2): 153–56. Bibcode:1995Geo....23..153Y. doi:10.1130/0091-7613(1995)023<0153:ANGDPO>2.3.CO;2. Retrieved 29 December 2015.
External links
- An image showing Pannotia according to Christopher Scotese. (it is referred to as the late Precambrian Supercontinent in the image).
- Torsvik, Trond Helge. "Palaeozoic Continent Margins: Late Cambrian (500 Ma)". Archived from the original on 23 July 2011. Retrieved 18 June 2010.
- Stampfli, G. M.; von Raumer, J. F.; Borel, G. D. (2002). "Paleozoic evolution of pre-Variscan terranes: from Gondwana to the Variscan collision" (PDF). Special Papers-Geological Society of America. 364: 263–280. Retrieved 4 January 2016. (see Fig. 3 for an Early Ordovician (490 Ma) reconstruction)