Explosive volcanic activity in the Mediterranean over the past 200,000 yr as recorded in deep-sea sediments

Author(s):  
J. KELLER ◽  
W.B.F. RYAN ◽  
D. NINKOVICH ◽  
R. ALTHERR
2015 ◽  
Vol 120 (11) ◽  
pp. 7253-7270 ◽  
Author(s):  
Yuta Isaji ◽  
Hodaka Kawahata ◽  
Naohiko Ohkouchi ◽  
Nanako O. Ogawa ◽  
Masafumi Murayama ◽  
...  
Keyword(s):  
Deep Sea ◽  
The Past ◽  

2010 ◽  
Vol 72 (2) ◽  
pp. 208-218 ◽  
Author(s):  
Cinzia Corinaldesi ◽  
Antonio Dell'Anno ◽  
Mirko Magagnini ◽  
Roberto Danovaro

1977 ◽  
Vol 7 (3) ◽  
pp. 363-371 ◽  
Author(s):  
Julius Fink ◽  
George J. Kukla

At least 17 times during the past 1.7 million years, the deposition of loess containing characteristic cold-resistant gastropods was interrupted by the development of temperate interglacial forests. This conclusion was reached in a study of paleomagnetically dated fossiliferous loess sequences in Krems, Austria and Brno, Czechoslovakia. Sequences of windblown loess interlayered with hillwash loams and steppe and forest soils exposed in brickyards around Brno and Praha, Czechoslovakia, revealed eight major depositional cycles within the Brunhes paleomagnetic epoch. We now report nine additional cycles of late and middle Matuyama age bringing the total number of glacial-interglacial cycles to 17, which occurred after the end of the Olduvai. The cycles are separated by marklines, levels of abrupt environmental change correlative with the terminations in deep-sea sediments. They are the boundaries between the windblown loess containing cold-resistant snail assemblages and between the clayey originally decalcified soils, accompanied by warmth loving Helix and Banatica snail faunas of hardwood forests. Because the presence of temperate forests in northwestern and central Europe is instrumental in the definition of an interglacial, each markline represents a glacial-interglacial boundary and each cycle is a glacial-interglacial cycle.


2021 ◽  
Author(s):  
Joel Guiot ◽  
Nicolas Bernigaud ◽  
Alberte Bondeau ◽  
Laurent Bouby

<p>Using a statistical emulator of a coupled climate-ecosystem model, this paper proposes a method to link the vine potential productivity and the viticulture extension in the Mediterranean area to global climate drivers, such as orbital parameters, solar and volcan activities and greenhouse gas concentrations. The emulator was calibrated on several tens of simulations of earth system models in various situations from the PMIP3 past (Last Glacial Maximum, Mid-Holocene, last millennium) and the CMIP5 future simulation up to 2100 under several RCP scenarios. The key climate variables produced by these simulations were introduced in an ecosystem model (BIOME4), so the ecosystem variables can be directly estimated from the global drivers. The large variation of situations used for calibration produces a robust emulator able to extrapolate to a large range of past and future climate states. Applied to the Mediterranean and European area, the emulator has been validated on several key periods of the past where the climate is known to have much changed. Finally, it was used to simulate the viticulture extension not only for these key past periods but also for different scenarios of the future, related to a global warming of 1.5°C, 2°C, 3°C and 5°C. Even if human groups are mainly responsible of viticulture extension, climate is a driver in the way that bad climate conditions may be a limit to extension or even a driver of regression.</p><p>The main findings are: (i) If the climate change projected for the future can be attributed to greenhouse gases increase as expected, the variations of the last millennia in the Mediterranean Basin can be attributed to the volcanic activity, the solar activity effect being negligeable; (ii) the effects of these volcanic forcing on the climate are not necessarily uniform across the basin and had a large impact on the viticulture as they were sufficiently important to be responsible of extension of viticulture on the whole Gaul during the Roman Climate Optimum; (iii) for the future, it is projected large difficulties for viticulture in Spain and North Africa. They will be particular important for a global warming of +3°C and more; (iv) there is little hope that an intense volcanic activity could slow down<strong> </strong>this regression.</p>


Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 481-492 ◽  
Author(s):  
T-H Peng

Changes in the ocean ventilation rate may be one of the causes for a net decrease of 100‰ Δ 14C in atmospheric CO2 over the last 8000 years. Ocean ventilation rates of the past can be derived from the 14C record preserved in planktonic and benthic foraminifera in deep-sea sediments. Results of 14C dating using accelerator mass spectrometry on deep sea sediments from the South China Sea show that the age differences between planktonic (G sacculifer) and benthic foraminifera increase from 1350 yr ca 7000 yr ago to 1590 yr at present. An 11-box geochemical model of global ocean circulation was used for this study. Both tree-ring-determined atmospheric 14C values and foraminifera 14C age differences are used as constraints to place limits on patterns of changes in ocean ventilation rates and in atmospheric 14C production rates. Results indicate: 1) 14C production rates in the atmosphere may have decreased by as much as 30% between 7000 and 3000 yr ago, and may have increased again by ca 15% in the past 2000 yr, and 2) the global ocean ventilation rate may not have been at steady state over the last 7000 yr, but may have slowed by as much as 35%.


2006 ◽  
Vol 45 (6) ◽  
pp. 435-450 ◽  
Author(s):  
Yusuke Suganuma ◽  
Kaori Aoki ◽  
Toshiya Kanamatsu ◽  
Toshitsugu Yamazaki

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