The results of the study reveal that mineral dust from the African regions of the Sahara and Sahel, which emit between 600 and 700 tonnes of dust a year, brought about the reddish soil in Mediterranean regions such as Mallorca and Sardinia between 12,000 and 25,000 years ago.
"The first hint of the relationship between African dust and certain soils in the region of the Mediterranean is their reddish or reddish-brown colour, similar to that of African aerosol filters, caused by their clay content", co-author of the study and researcher at the Centre for Ecological Research and Forestry Applications (CREAF) at the Universidad Autónoma de Barcelona, Anna Ávila explained to SINC.
The study, which has been published in Quaternary Science Reviews, finds that African mineral dust additions "play an important role" in the origin of the soils (palaeosols) in the Mediterranean region, namely on the island of Mallorca. The results resemble those published regarding the soils on Sardinia, "which indicates the likelihood of Africa being a common source".
In turn, "African dust explains the origin of the 'terra rossa' soils in the Mediterranean region located on top of mother carbonate rock," Ávila added.
In order to explain the origin of the reddish soils, the researchers considered three hypotheses: the non carbonate residual accumulation theory (soils are derived from the product of non carbonate weathering of the mother carbonate rock), the ascending 'sesquioxide' theory (accumulation of iron and aluminium hydroxides following capillary ascent from the bedrock) and the non-native soil accumulation theory (soil is formed by external sources, including airborne contributions).
The first two hypotheses were discarded due to the geochemical composition of the trace elements of red soils and the underlying rock being different. "The hypothesis of non-native (external) contribution was reinforced due to the geochemical value of the land coinciding with that of African dust," the scientist stated.
However, although the analysis of the soil indicates that African dust is the main contributor to the formation of the palaeosol, "the underlying rock also contributes, probably with residual quartz," the researcher added.
Origin and Destination of African Dust
"Terra rossa" (red soil in Italian) is located on carbonate rock (with a high content of carbonate) and is spread throughout the Iberian Peninsula, the South of France, the islands in the Mediterranean, Italy and along the coast of the Adriatic Sea, from Slovenia to Greece. The largest sources of airborne mineral dust can be found in the Sahara and Sahel regions, with emissions of between 600 and 700 tonnes per year. The destination of this dust has recently aroused great interest among the scientific community for various reasons.
Apart from the formation of red soils, African dust has "adverse effects on human health, such as respiratory problems and reduced visibility. It also arouses interest due to its implications where climate change is concerned, with the role that mineral aerosols play in the radiation balance, nutrient deposition and oceanic fertilisation", Ávila explained.
Muhs, Daniel R.; Budahn, James; Ávila, Anna; Skipp, Gary; Freeman, Joshua; Patterson, DeAnna. "The role of African dust in the formation of Quaternary soils on Mallorca, Spain and implications for the genesis of Red Mediterranean soils" Quaternary Science Reviews 29(19-20): 2518-2543, septiembre de 2010.
SINC | EurekAlert!
Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter
17.08.2017 | Swansea University
Climate change: In their old age, trees still accumulate large quantities of carbon
17.08.2017 | Universität Hamburg
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences