World Library  
Flag as Inappropriate
Email this Article
 

Toba catastrophe theory

Toba catastrophe theory
Illustration of what the eruption might have looked like from approximately 26 miles (42 km) above Pulau Simeulue.
Volcano Toba supervolcano
Date 74,100—75,900 years ago
Location Sumatra, Indonesia
VEI 8
Impact Most recent supereruption; plunged Earth into 6 years of volcanic winter, possibly significant changes to regional topography.[1]
Lake Toba is the resulting crater lake.

The Toba supereruption was a supervolcanic eruption that occurred some time between 69,000 and 77,000 years ago at the site of present-day Lake Toba (Sumatra, Indonesia). It is one of the Earth's largest known eruptions. The Toba catastrophe hypothesis holds that this event caused a global volcanic winter of 6–10 years and possibly a 1,000-year-long cooling episode.

In 1993, science journalist Ann Gibbons suggested a link between the eruption and a population bottleneck in human evolution, and Michael R. Rampino of New York University and Stephen Self of the University of Hawaii at Manoa gave support to the idea. In 1998, the bottleneck theory was further developed by Stanley H. Ambrose of the University of Illinois at Urbana-Champaign.

Both the link and global winter theories are highly controversial.

The Toba event is the most closely studied super-eruption.[2][3][4]

Contents

  • Supereruption 1
  • Volcanic winter and cooling 2
  • Genetic bottleneck theory 3
    • Genetic bottlenecks in other mammals 3.1
  • Migration after Toba 4
  • See also 5
  • Citations and notes 6
  • References 7
  • External links 8

Supereruption

The Toba eruption or Toba event occurred at the present location of Lake Toba, in Indonesia, about 75000±900 years Before Present (BP).[5][6] This eruption was the last and largest of four eruptions of Toba during the Quaternary period, and is also recognized from its diagnostic horizon of ashfall, the youngest Toba tuff (YTT).[7][8] It had an estimated volcanic explosivity index of 8 (described as "apocalyptic"), or a magnitude ≥ M8; it made a sizable contribution to the 100×30 km caldera complex.[9] Dense-rock equivalent (DRE) estimates of eruptive volume for the eruption vary between 2000 km3 and 3000 km3 – the most common DRE estimate is 2800 km3 (about 7×1015 kg) of erupted magma, of which 800 km3 was deposited as ash fall.[10]

The erupted mass was 100 times greater than that of the largest volcanic eruption in recent history, the 1815 eruption of Mount Tambora in Indonesia, which caused the 1816 "Year Without a Summer" in the northern hemisphere.[11] Toba's erupted mass deposited an ash layer approximately 15 centimetres (6 inches) thick over the whole of South Asia. A blanket of volcanic ash was also deposited over the Indian Ocean, and the Arabian Sea and South China Sea.[12] Deep-sea cores retrieved from the South China Sea have extended the known reach of the eruption, suggesting that the 2800 km3 calculation of the erupted mass is a minimum value or even an underestimation.[13]

Volcanic winter and cooling

The Toba eruption apparently coincided with the onset of the last glacial period. Michael L. Rampino and Stephen Self argue that the eruption caused a "brief, dramatic cooling or 'volcanic winter'", which resulted in a drop of the global mean surface temperature by 3–5 °C and accelerated the transition from warm to cold temperatures of the last glacial cycle.[14] Evidence from Greenland ice cores indicates a 1,000-year period of low δ18O and increased dust deposition immediately following the eruption. The eruption may have caused this 1,000-year period of cooler temperatures (stadial), two centuries of which could be accounted for by the persistence of the Toba stratospheric loading.[15] Rampino and Self believe that global cooling was already underway at the time of the eruption, but that the process was slow; YTT "may have provided the extra 'kick' that caused the climate system to switch from warm to cold states".[16] Although Clive Oppenheimer rejects the hypothesis that the eruption triggered the last glaciation,[17] he agrees that it may have been responsible for a millennium of cool climate prior to the 19th Dansgaard-Oeschger event.[18]

According to Alan Robock, who has also published nuclear winter papers, the Toba eruption did not precipitate the last glacial period. However assuming an emission of six billion tons of sulphur dioxide, his computer simulations concluded that a maximum global cooling of approximately 15 °C occurred for three years after the eruption, and that this cooling would last for decades, devastating life.[19] Because the saturated adiabatic lapse rate is 4.9 °C/1,000 m for temperatures above freezing,[20] the tree line and the snow line were around 3,000 m (9,900 ft) lower at this time. The climate recovered over a few decades, and Robock found no evidence that the 1,000-year cold period seen in Greenland ice core records had resulted from the Toba eruption. In contrast, Oppenheimer believes that estimates of a drop in surface temperature by 3–5 °C are probably too high, and he suggests that temperatures dropped only by 1 °C.[21] Robock is said to have failed to take into account the temporal evolution of the aerosol size distribution, which turned out to be an important diminishing factor for the volcanic climate signal, and that the climate response to the Toba super-eruption was regional changes.[22] His critics claim the sulphur dioxide yield was not as high as 6 billion tons, based on experimental petrology, that it was closer to Tambora-sized.[23] Robock has criticized Oppenheimer's analysis, arguing that it is based on simplistic T-forcing relationships.[24]

Archaeologists, led by University of Oxford's Dr Christine Lane, in 2013, reported finding a microscopic layer of glassy volcanic ash in sediments of Lake Malawi, and definitively linked the ash to the 75,000-year-old Toba super-eruption, but found no change in fossil type close to the ash layer, something that would be expected following a severe volcanic winter. They concluded that the largest known volcanic eruption in the history of the human species did not significantly alter the climate of East Africa,[25][26] attracting criticism from Richard Roberts.[27] Lane explained, "We examined smear slides at a 2-mm interval, corresponding to subdecadal resolution, and X-ray fluorescence scans run at 200-µm intervals correspond to subannual resolution. We observed no obvious change in sediment composition or Fe/Ti ratio, suggesting that no thermally driven overturn of the water column occurred following the Toba supereruption."[28] In 2015, a new study of climate of East Africa supported Lane's conclusion.[29]

Genetic bottleneck theory

The Toba eruption has been linked to a genetic bottleneck in human evolution about 50,000 years ago,[30][31] which may have resulted from a severe reduction in the size of the total human population due to the effects of the eruption on the global climate.[32]

According to the genetic bottleneck theory, between 50,000 and 100,000 years ago, human populations sharply decreased to 3,000–10,000 surviving individuals.[33][34] It is supported by genetic evidence suggesting that today's humans are descended from a very small population of between 1,000 and 10,000 breeding pairs that existed about 70,000 years ago.[35]

Proponents of the genetic bottleneck theory (including Robock) suggest that the Toba eruption resulted in a global ecological disaster, including destruction of vegetation along with severe drought in the tropical rainforest belt and in monsoonal regions. For example, a 10-year volcanic winter triggered by the eruption could have largely destroyed the food sources of humans and caused a severe reduction in population sizes.[24] Τhese environmental changes may have generated population bottlenecks in many species, including hominids;[36] this in turn may have accelerated differentiation from within the smaller human population. Therefore, the genetic differences among modern humans may reflect changes within the last 70,000 years, rather than gradual differentiation over millions of years.[37]

Other research has cast doubt on a link between Toba and a genetic bottleneck. For example, ancient stone tools in southern India were found above and below a thick layer of ash from the Toba eruption and were very similar across these layers, suggesting that the dust clouds from the eruption did not wipe out this local population.[38][39][40] Additional archaeological evidence from Southern and Northern India also suggests a lack of evidence for effects of the eruption on local populations, leading the authors of the study to conclude, "many forms of life survived the supereruption, contrary to other research which has suggested significant animal extinctions and genetic bottlenecks".[41] However, evidence from pollen analysis has suggested prolonged deforestation in South Asia, and some researchers have suggested that the Toba eruption may have forced humans to adopt new adaptive strategies, which may have permitted them to replace Neanderthals and "other archaic human species".[42] This has been challenged by evidence for the presence of Neanderthals in Europe and Homo floresiensis in Southeastern Asia who survived the eruption by 50,000 and 60,000 years, respectively.[43]

Additional caveats to the Toba-induced bottleneck theory include difficulties in estimating the global and regional climatic impacts of the eruption and lack of conclusive evidence for the eruption preceding the bottleneck.[44] Furthermore, genetic analysis of Alu sequences across the entire human genome has shown that the effective human population size was less than 26,000 at 1.2 million years ago; possible explanations for the low population size of human ancestors may include repeated population bottlenecks or periodic replacement events from competing Homo subspecies.[45]

Genetic bottlenecks in other mammals

Some evidence points to genetic bottlenecks in other animals in the wake of the Toba eruption: the populations of the Eastern African chimpanzee,[46] Bornean orangutan,[47] central Indian macaque,[48] the cheetah, the tiger,[49] and the separation of the nuclear gene pools of eastern and western lowland gorillas,[50] all recovered from very low numbers around 70,000–55,000 years ago.

Migration after Toba

The exact geographic distribution of human populations at the time of the eruption is not known, and surviving populations may have lived in Africa and subsequently migrated to other parts of the world. Analyses of mitochondrial DNA have estimated that the major migration from Africa occurred 60,000–70,000 years ago,[51] consistent with dating of the Toba eruption to around 66,000–76,000 years ago.

However, recent archeological finds have suggested that a human population may have survived in Jwalapuram, Southern India.[52] Moreover, it has also been suggested that nearby hominid populations, such as Homo floresiensis on Flores, survived because they lived upwind of Toba.[53]

See also

Citations and notes

  1. ^ John Savino; Marie D. Jones (2007). Supervolcano: The Catastrophic Event That Changed the Course of Human History: Could Yellowstone Be Next. Career Press. p. 140.  
  2. ^ Chesner & others 1991, p. 200; Jones 2007, p. 174; Oppenheimer 2002, pp. 1593–1594; Ninkovich & others 1978
  3. ^ "The Toba Supervolcano And Human Evolution". Toba.arch.ox.ac.uk. Retrieved 2013-08-05. 
  4. ^ "The Geological Society : Super-eruptions" (PDF). Geo.mtu.edu. Retrieved 2015-03-28. 
  5. ^ Ninkovich & others 1978.
  6. ^ Chesner & others 1991.
  7. ^ Chesner & others 1991, p. 200; Jones 2007, p. 174; Oppenheimer 2002, pp. 1593–1594; Ninkovich & others 1978
  8. ^ Rose & Chesner 1987, p. 913; Zielinski & Mayewski 1996.
  9. ^ Oppenheimer 2002, p. 1593.
  10. ^ Jones 2007, p. 174; Rose & Chesner 1987, p. 913.
  11. ^ Petraglia & others 2007, p. 114; Zielinski & others 1996, p. 837.
  12. ^ Jones 2007, p. 173
  13. ^ Jones 2007, p. 174; Oppenheimer 2002. pp. 1593–1596.
  14. ^ Rampino & Self 1993a, passim.
  15. ^ Zielinski & others 1996, pp. 837–840.
  16. ^ Rampino & Self 1992, p. 52; Rampino & Self 1993a, p. 277.
  17. ^ Robock & others (2009) seem to agree on that.
  18. ^ Oppenheimer 2002, p. 1606.
  19. ^ Robock & others 2009.
  20. ^ "IUPAC Gold Book - adiabatic lapse rate in atmospheric chemistry". Goldbook.iupac.org. 2014-02-24. Retrieved 2015-03-28. 
  21. ^ Oppenheimer 2002, pp. 1593, 1601.
  22. ^ Timmreck, C (2012). "Climate response to the Toba super-eruption: Regional changes". Quaternary International. 
  23. ^ Chesner, C (2010). "A melt inclusion study of the Toba Tuffs, Sumatra, Indonesia". Journal of Volcanology and Geothermal Research. 
  24. ^ a b Robock & others 2009.
  25. ^ "Doubt over 'volcanic winter' after Toba super-eruption. 2013". Phys.org. 2013-05-02. Retrieved 2013-08-05. 
  26. ^ "Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka" (PDF). Pnas.org. Retrieved 2015-03-28. 
  27. ^ "Toba supereruption: Age and impact on East African ecosystems". 
  28. ^ Lane, CS (2013). "Reply to Roberts et al.: A subdecadal record of paleoclimate around the Youngest Toba Tuff in Lake Malawi". Proceedings of the National Academy of Sciences.  
  29. ^ Jackson, LJ (2015). "High-resolution paleoecological records from Lake Malawi show no significant cooling associated with the Mount Toba supereruption at ca. 75 ka". Geology.  
  30. ^ Gibbons 1993, p. 27
  31. ^ Rampino & Self (1993)
  32. ^ Ambrose 1998, passim; Gibbons 1993, p. 27; McGuire 2007, pp. 127–128; Rampino & Ambrose 2000, pp. 78–80; Rampino & Self 1993b, pp. 1955.
  33. ^ Ambrose 1998; Rampino & Ambrose 2000, pp. 71, 80.
  34. ^ "Science & Nature - Horizon - Supervolcanoes". BBC.co.uk. Retrieved 2015-03-28. 
  35. ^ "When humans faced extinction". BBC. 2003-06-09. Retrieved 2007-01-05. 
  36. ^ Rampino & Ambrose 2000, p. 80.
  37. ^ Ambrose 1998, pp. 623–651.
  38. ^ "Mount Toba Eruption – Ancient Humans Unscathed, Study Claims". Retrieved 2008-04-20. 
  39. ^ Sanderson, Katherine (July 2007). "Super-eruption: no problem?" (– Scholar search).  
  40. ^  
  41. ^ See also "Newly Discovered Archaeological Sites in India Reveals Ancient Life before Toba". Anthropology.net. 25 February 2010. Retrieved 28 February 2010. 
  42. ^ "Supervolcano Eruption In Sumatra Deforested India 73,000 Years ago". Science Daily. 24 November 2009. ; Williams & others 2009.
  43. ^ "Environmental Impact of the 73 ka Toba Super-eruption in South Asia – ScienceDirect". Anthropology.net. 24 November 2009. Retrieved 3 March 2010. ; "New Evidence Shows Populations Survived the Toba Super-eruption 74,000 Years ago". University of Oxford. 22 February 2009. 
  44. ^ Oppenheimer 2002, pp. 1605, 1606.
  45. ^ If these results are accurate, then, even before the emergence of Homo sapiens in Africa, Homo erectus population was unusually small when the species was spreading around the world. See Huff & others 2010, p.6; Gibbons 2010.
  46. ^ Goldberg 1996.
  47. ^ Steiper 2006.
  48. ^ Hernandez & others 2007.
  49. ^ Luo & others 2004.
  50. ^ Thalman & others 2007.
  51. ^ "New 'Molecular Clock' Aids Dating Of Human Migration History".  
  52. ^ Petraglia & others 2007, passim.
  53. ^ "Human species before and after the genetic bottleneck associated with Toba". Andaman.org. Retrieved 2012-03-10. 

References

  • Ambrose, Stanley H. (1998). "Late Pleistocene human population bottlenecks, volcanic winter, and differentiation of modern humans".  
  • Atkinson, QD; Gray, RD; Drummond, AJ (January 2009), "Bayesian coalescent inference of major human mitochondrial DNA haplogroup expansions in Africa", Proceedings. Biological Sciences / the Royal Society 276 (1655): 367–73,  
  • Behar, Doron M.; Villems, Richard; Soodyall, Himla; Blue-Smith, Jason; Pereira, Luisa; Metspalu, Ene; Scozzari, Rosaria; Makkan, Heeran; Tzur, Shay; Comas, David; Bertranpetit, Jaume; Quintana-Murci, Lluis; Tyler-Smith, Chris; Wells, R. Spencer; Rosset, Saharon; The Genographic Consortium (May 2008), "The dawn of human matrilineal diversity", American Journal of Human Genetics 82 (5): 1130–40,  
  • Cann, RL; Stoneking, M; Wilson, AC (1987), "Mitochondrial DNA and human evolution", Nature 325 (6099): 31–6,  
  • Chesner, C.A.; Westgate, J.A.; Rose, W.I.; Drake, R.; Deino, A. (March 1991). "Eruptive History of Earth's Largest Quaternary caldera (Toba, Indonesia) Clarified" (PDF). Geology 19: 200–203.  
  • Cox, MP (August 2008), "Accuracy of molecular dating with the rho statistic: deviations from coalescent expectations under a range of demographic models", Hum. Biol. 80 (4): 335–57,  
  •  
  • Endicott, SY; P, SY; Ho (April 2008), "A Bayesian evaluation of human mitochondrial substitution rates", Am. J. Hum. Genet. 82 (4): 895–902,  
  • Endicott, P; Ho, SY; Metspalu, M; Stringer, C (September 2009), "Evaluating the mitochondrial timescale of human evolution", Trends Ecol. Evol. (Amst.) 24 (9): 515–21,  
  • Excoffier, L; Yang, Z (October 1999), "Substitution rate variation among sites in mitochondrial hypervariable region I of humans and chimpanzees", Mol. Biol. Evol. 16 (10): 1357–68,  
  • Felsenstein, J (April 1992), "Estimating effective population size from samples of sequences: inefficiency of pairwise and segregating sites as compared to phylogenetic estimates", Genet. Res. 59 (2): 139–47,  
  • Gibbons, Ann (1 October 1993). "Pleistocene Population Explosions". Science 262 (5130): 27–28.  
  • Gibbons, Ann (19 January 2010). "Human Ancestors Were an Endangered Species". ScienceNow. 
  • Goldberg, T.L. (1996). Genetics and biogeography of East African chimpanzees (Pan troglodytes schweinfurthii). Harvard University, unpublished PhD Thesis. 
  • Gonder, MK; Mortensen, HM; Reed, FA; de Sousa, A; Tishkoff, SA (December 2007), "Whole-mtDNA genome sequence analysis of ancient African lineages", Mol. Biol. Evol 24 (3): 757–68,  
  • Hernandez, R.D.; Hubisz, M.J.; Wheeler, D.A.; Smith, D.G.; Ferguson, B.; Ryan, D.; Rogers, J.; Nazareth, L.; Indap, A.; Bourquin, T.; McPherson, J.; Muzny, D.; Gibbs, R.; Nielsen, R.; Bustamante, C.D. (2007). "Demographic histories and patterns of linkage disequilibrium in Chinese and Indian Rhesus macaques". Science 316: 240–243.  
  • Huff, Chad. D; Xing, Jinchuan; Rogers, Alan R.; Witherspoon, David; Jorde, Lynn B. (19 January 2010). "Mobile Elements Reveal Small Population Size in the Ancient Ancestors of Homo Sapiens" (PDF). Proceedings of the National Academy of Sciences 107 (5): 1–6.  
  • Jones, S. C. (2007). "The Toba Supervolcanic Eruption: Tephra-Fall Deposits in India and Paleoanthropological Implications". In Petraglia, M. D.; Allchin, B. The Evolution and History of Human Populations in South Asia. Springer. pp. 173–200.  
  • Ingman, M; Kaessmann, H; Pääbo, S; Gyllensten, U (December 2000), "Mitochondrial genome variation and the origin of modern humans", Nature 408 (6813): 708–13,  
  • Kaessmann, H; Pääbo, S (January 2002), "The genetical history of humans and the great apes", J. Intern. Med. 251 (1): 1–18,  
  • Linz, B.; et al. (February 2007). "Helicobacter pylori"An African origin for the intimate association between humans and . Nature 445 (7130): 915–8.  
  • Loewe, L; Scherer First1 = S, Siegfried (November 1997), "Mitochondrial Eve: The Plot Thickens", Trends in Ecology & Evolution 12 (11): 422–3,  
  • Luo, S.-J.; Kim, J.-H.; Johnson, W.E.; Van der Walt, J.; Martenson, J.; Yuhid, N.; Miquelle, D.G.; Uphyrkina, O.; Goodrich, J.M.; Quigley, H.B.; Tilson, R.; Brady, G.; Martelli, P.; Subramaniam, V.; McDougal, C.; Hean, S.; Huang, S.-Q.; Pan, W.; Karanth, U.K.; Sunquist, M.; Smith, J.L.D.; O'Brien, S.J. (2004). )"Panthera tigris"Phylogeography and genetic ancestry of tigers (. PLoS Biology 2 (12): 2275–2293.  
  • Maca-Meyer, N; González, AM; Larruga, JM; Flores, C; Cabrera, VM (2001), "Major genomic mitochondrial lineages delineate early human expansions", BMC Genet. 2: 13,  
  • McGuire, W.J. (2007). "The GGE Threat: Facing and Coping with Global Geophysical Events". In Bobrowsky, Peter T.; Rickman, Hans. Comet/Asteroid Impacts and Human Society: an Interdisciplinary Approach. Springer. pp. 123–141.  
  • Nielsen, R; Beaumont, MA (March 2009), "Statistical inferences in phylogeography", Mol. Ecol. 18 (6): 1034–47,  
  • Ninkovich, D.; N.J. Shackleton; A.A. Abdel-Monem; J.D. Obradovich; G. Izett (7 December 1978). "K−Ar age of the late Pleistocene eruption of Toba, north Sumatra". Nature 276 (276): 574–577.  
  • Oppenheimer, Clive (2002), "Limited global change due to largest known Quaternary eruption, Toba ≈74 kyr BP?,", Quaternary Science Reviews 21: 1593–1609,  
  • Oppenheimer, Stephen (2004), The Real Eve: Modern Man's Journey Out of Africa, New York, NY: Carroll & Graf,  
  • Parsons, TJ; Muniec, DS; Sullivan, K; Woodyatt, N; et al. (April 1997), "A high observed substitution rate in the human mitochondrial DNA control region", Nat. Genet. 15 (4): 363–8,  
  • Petraglia, M.; Korisettar, R.; Boivin, N.; Clarkson, C.; Ditchfield, P.; Jones, S.; Koshy, J.; Lahr, M.M.; Oppenheimer, C.; Pyle, D.; Roberts, R.; Schwenninger, J.-C.; Arnold, L.; White, K. (6 July 2007). "Middle Paleolithic Assemblages from the Indian Subcontinent Before and After the Toba Super-eruption" (PDF). Science 317 (5834): 114–116.  
  • Rampino, Michael R.; Self, Stephen (2 September 1992). "Volcanic Winter and Accelerated Glaciation following the Toba Super-eruption" (PDF). Nature 359 (6390): 50–52.  
  • Rampino, Michael R.; Self, Stephen (1993). "Climate–Volcanism Feedback and the Toba Eruption of ~74,000 Years ago" (PDF). Quaternary Research 40: 269–280.  
  • Rampino, Michael R.; Self, Stephen (24 December 1993). "Bottleneck in the Human Evolution and the Toba Eruption". Science 262 (5142): 1955.  
  • Robock, A.; Ammann, C.M.; Oman, L.; Shindell, D.; Levis, S.; Stenchikov, G. (2009). "Did the Toba Volcanic Eruption of ~74k BP Produce Widespread Glaciation?".  
  • Rose, W.I.; Chesner, C.A. (October 1987). "Dispersal of Ash in the Great Toba Eruption, 75 ka" (PDF). Geology 15 (10): 913–917.  
  • Schaffner, SF (2004), "The X chromosome in population genetics", Nat Rev Genet 5 (1): 43–51,  
  • Self, Stephen; Blake, Stephen (February 2008). "Consequences of Explosive Supereruptions". Elements 4 (1): 41–46.  
  • Soares, P; Ermini, L; Thomson, N; Mormina, M; Rito, T; Röhl, A; Salas, A; Oppenheimer, S; Macaulay, V; Richards, MB (June 2009), "Correcting for purifying selection: an improved human mitochondrial molecular clock",  
  • Steiper, M.E. (2006). "Population history, biogeography, and taxonomy of orangutans (Genus: Pongo) based on a population genetic meta-analysis of multiple loci". Journal of Human Evolution 50: 509–522.  
  • Takahata, N (January 1993), "Allelic genealogy and human evolution", Mol. Biol. Evol. 10 (1): 2–22,  
  • Thalman, O.; Fisher, A.; Lankester, F.; Pääbo, S.; Vigilant, L. (2007). "The complex history of gorillas: insights from genomic data". Molecular Biology and Evolution 24: 146–158.  
  • Vigilant, L; Pennington, R; Harpending, H; Kocher, TD; Wilson, AC (December 1989), "Mitochondrial DNA sequences in single hairs from a southern African population", Proc. Natl. Acad. Sci. U.S.A. 86 (23): 9350–4,  
  • Vigilant, L; Stoneking, M; Harpending, H; Hawkes, K; Wilson, AC (September 1991), "African populations and the evolution of human mitochondrial DNA", Science 253 (5027): 1503–7,  
  • Watson E, Forster P, Richards M, Bandelt HJ (September 1997), "Mitochondrial footprints of human expansions in Africa", Am. J. Hum. Genet. 61 (3): 691–704,  
  • Williams, Martin A.J.; Stanley H. Ambrose; Sander van der Kaars; 4 Carsten Ruehlemann; 5 Umesh Chattopadhyaya; 6 Jagannath Pal; 7 Parth R. Chauhan (30 December 2009). "Environmental impact of the 73 ka Toba super-eruption in South Asia". Palaeogeography, Palaeoclimatology, Palaeoecology (Elsevier) 284 (3–4): 295–314.  
  • Zielinski, A.; Mayewski, P. A.; Meeker, L. D.; Whitlow, S.; Twickler, M. S.; Taylor, K. (1996). "Potential Atmospheric impact of the Toba mega-eruption ~71'000 years ago". Geophysical Research Letters 23 (8): 837–840.  
  • Zielinski, G. A.; Mayewski, P. A.; Meeker, L.D.; Whitlow, S.; Twickler, M.S.; Taylor, K. (1996). "Potential Atmospheric Impact of the Toba Mega‐Eruption ~71,000 years ago" (PDF). Geophysical Research Letters 23 (8): 837–840.  

External links

  • Population Bottlenecks and Volcanic Winter
  • Toba Volcano by George Weber at the Wayback Machine (archived April 22, 2011)
  • "The proper study of mankind" – Article in The Economist
  • Homepage of Professor Stanley H. Ambrose
  • 1998 article based on news release regarding Ambrose's paper
  • Mount Toba: Late Pleistocene human population bottlenecks, volcanic winter, and differentiation of modern humans by Professor Stanley H. Ambrose, Department of Anthropology, University Of Illinois, Urbana, USA; Extract from "Journal of Human Evolution" [1998] 34, 623–651
  • Journey of Mankind by The Bradshaw Foundation – includes discussion on Toba eruption, DNA and human migrations
  • Geography Predicts Human Genetic Diversity ScienceDaily (Mar. 17, 2005) – By analyzing the relationship between the geographic location of current human populations in relation to East Africa and the genetic variability within these populations, researchers have found new evidence for an African origin of modern humans.
  • Out Of Africa – Bacteria, As Well: Homo Sapiens And H. Pylori Jointly Spread Across The Globe ScienceDaily (Feb. 16, 2007) – When man made his way out of Africa some 60,000 years ago to populate the world, he was not alone: He was accompanied by the bacterium Helicobacter pylori...; illus. migration map.
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.