K–Ar age of the late Pleistocene eruption of Toba, north Sumatra

Ninkovich, Dragoslav; Shackleton, N. J.; Abdel-Monem, A.A.; Obradovich, John D.; Izett, G. A.

doi:10.1038/276574a0

Cited by 170 publications

(61 citation statements)

References 9 publications

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“…The δ 18 θ age for layer A is 0.075 ± 0.004 Ma. This age matches the previously established value of 75,000 yr for the Toba ash (Ninkovich et al, 1978Rose andChesner, 1987, 1988). The age of layer B cannot be differentiated from layer A by paleomagnetic or δ 18 θ means, further supporting the conclusion that it is a misplaced part of layer A.…”

Section: Dating Of the Tephra Layerssupporting

confidence: 73%

Neogene Tephrochronology from Site 758 of the Northern Ninetyeast Ridge: Indonesian Arc Volcanism of the Past 5 Ma

Dehn¹,

Farrell²,

Schmincke³

1991

Proceedings of the Ocean Drilling Program

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A tephrochronology of the past 5 Ma is constructed with ash layers recovered from Neogene sediments during drilling at ODP Leg 121 Site 758 on northern Ninetyeast Ridge. The several hundred tephra layers observed in the first 80 m of cores range in thickness from a few millimeters to 34 cm. Seventeen tephra layers, at least 1 cm thick, were sampled and analyzed for major elements. Relative ages for the ash layers are estimated from the paleomagnetic and δ 18 θ chronostratigraphy. The ash layers comprise about 1.7% by volume of the sediments recovered in the first 72 m. The median grain size of the ashes is about 75 µm, with a maximum of 150 µm. The ash consists of rhyolitic bubble junction and pumice glass shards. Blocky and platy shards are in even proportion (10%-30%) and are dominated by bubble wall shards (70%-90%). The crystal content of the layers is always less than 2%, with Plagioclase and alkali feldspar present in nearly every layer. Biotite was observed only in the thickest layers.The major element compositions of glass and feldspar reflect fractionation trends. Three groupings of ash layers suggest different provenances with distinct magmatic systems. Dating by δ 18 θ and paleomagnetic reversals suggests major marine ash-layer-producing eruptions (marine tephra layers > 1 cm in thickness) occur roughly every approximately 414,000 yr. This value correlates well with landbased studies and dates of Pleistocene Sumatran tuffs (average 375,000-yr eruptive interval). Residence times of the magmatic systems defined by geochemical trends are 1.583, 2.524, and 1.399 Ma. The longest time interval starts with the least differentiated magma.The Sunda Arc, specifically Sumatra, is inferred to be the source region for the ashes. Four of the youngest five ash layers recovered correlate in time and in major element chemistry to ashes observed on land at the Toba caldera.

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Section: Dating Of the Tephra Layerssupporting

confidence: 73%

Neogene Tephrochronology from Site 758 of the Northern Ninetyeast Ridge: Indonesian Arc Volcanism of the Past 5 Ma

Dehn¹,

Farrell²,

Schmincke³

1991

Proceedings of the Ocean Drilling Program

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“…The total volume of pyroclastic material erupted at Toba was at least 2800 km 3 , of which 800 km 3 is estimated to be dispersed ash, as calculated from an isopach constructed from more than a dozen piston-core locations in the Indian Ocean widely distributed over nearly 4 million square kilometers (Rose and Chesner, 1987). This is the largest documented Quaternary marine ash layer (Ninkovich et al, 1978).…”

Section: Summary Of Observations On Ash In Cores From Sites 578 Throumentioning

confidence: 99%

“…Obviously, these represent eruptions much larger than the May 1980 Mount St. Helens and Roseau eruptions. Indeed, such thicknesses at >1500 km distance from sources suggest comparison to the great eruption at Toba, Sumatra, at 75 Ka, which produced an ash bed uniformly 8-10 cm thick at distances from 1000 to 2000 km from the volcano (Ninkovich et al, 1978). The total volume of pyroclastic material erupted at Toba was at least 2800 km 3 , of which 800 km 3 is estimated to be dispersed ash, as calculated from an isopach constructed from more than a dozen piston-core locations in the Indian Ocean widely distributed over nearly 4 million square kilometers (Rose and Chesner, 1987).…”

Section: Summary Of Observations On Ash In Cores From Sites 578 Throumentioning

confidence: 99%

Volcanic Ash and Pumice at Shatsky Rise: Sources, Mechanisms of Transport, and Bearing on Atmospheric Circulation

Natland¹

1993

Proceedings of the Ocean Drilling Program

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Air-fall volcanic ash and pumice were recovered from 22 intervals in upper Miocene-Pleistocene nannofossil oozes cored in Hole 8IOC on Shatsky Rise, northwest Pacific. Shatsky Rise is near the eastern limit of ash falls produced by explosive volcanism in arc systems in northern Japan and the Kuriles, more than 1600 km away. Electron probe analyses establish that the ash beds and pumice pebbles are andesitic to rhyolitic in composition, and belong to both tholeiitic and high-alumina lineages similar to tephra from Japanese volcanoes. High-speed winds in the polar-front and subtropical jets are evidently what propelled the ash for such a distance. The pumice arrived by flotation, driven from the same directions by winds, waves, and currents. It is not ice-rafted debris from the north. One thick pumice bed probably was deposited when a large pumice mat passed over Shatsky Rise.Far more abundant ash occurs in sediments cored at DSDP Sites 578 through 580, about 500 km west of Shatsky Rise. Most of the ash and pumice at Shatsky Rise can be correlated with specific ash beds at 1, 2, or all 3 of these sites by interpolating to precisely determined magnetic reversal sequences in the cores. Most of the correlations are to thick ash layers (5.7 ±3.0 cm) at one or more sites. These must represent extremely large eruptions that spread ash over very wide areas. Whereas several of the thicker correlative ashes fell from elongate east-trending plumes directed from central Japan, the majority of them-dating from about 2 Ma-came from the North Honshu and Kurile arc systems to the northwest. This direction probably was in response to both long-term and seasonal fluctuations in the location and velocity of the polar-front jet, and to more vigorous winter storm fronts originating over glaciated Siberia.

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“…There were at least 5 major mass extinctions, en route, caused by falling sea-levels, cosmic events, ocean anoxia, etc. In more recent times, for example, Homo erectus was perhaps annihilated by the Toba catastrophe (youngest of mass extinctions) some 73,000 years ago [12,13]. Similarly, plants have also developed their own molecular phylogeny (e.g.…”

Section: Introductionmentioning

confidence: 99%

Perspectives of Human Development: Time, Space, and Chrononutrition

Wilson

Hungin²,

Griffiths³

et al. 2012

TONUTRAJ

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This chapter attempts to step backward in time and space, to consider evolution in the context of chronobiology and chronomics and to then focus on how this science, pioneered by Professor Halberg and his team at the University of Minnesota, can bring improved health benefits to mankind. Although being mindful of this old yet formally modern science, care is taken to include many practical considerations that have a tendency to be sometimes undervalued in research.Evolution continues under the omnipresence of gravity, changing electromagnetic forces, time, space, and Earth's climate and environment as an ecological biogeographical phenomenon that took place extremely slowly in geological time but is now undergoing change at an extraordinary pace in recent times of human evolution and adaption to their environment [1]. Already about 1 out of 3 billion people go hungry [2] (and currently in overall decline) and by 2050 the estimated population is about 9 billion [3]. Great challenges to reduce poverty and hunger lie ahead: people need to be fed but safely, the risk of inflammatory diseases such as gastrointestinal and cardiovascular disorders needs to be reduced: and one potential area of research concerns chrononutrition. It is by understanding the chronobiological science that underpins health that will enable such goals to be reached.

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K–Ar age of the late Pleistocene eruption of Toba, north Sumatra

Cited by 170 publications

References 9 publications

Neogene Tephrochronology from Site 758 of the Northern Ninetyeast Ridge: Indonesian Arc Volcanism of the Past 5 Ma

Neogene Tephrochronology from Site 758 of the Northern Ninetyeast Ridge: Indonesian Arc Volcanism of the Past 5 Ma

Volcanic Ash and Pumice at Shatsky Rise: Sources, Mechanisms of Transport, and Bearing on Atmospheric Circulation

Perspectives of Human Development: Time, Space, and Chrononutrition

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