Featured Research

from universities, journals, and other organizations

Chocolate and diamonds: Why volcanoes could be 'a girl's best friend'

Date:
May 16, 2012
Source:
University of Southampton
Summary:
Scientists have discovered a previously unrecognized volcanic process, similar to one that is used in chocolate manufacturing, which gives important new insights into the dynamics of volcanic eruptions. The scientists investigated how a process called ‘fluidized spray granulation’ can occur during kimberlite eruptions to produce well-rounded particles containing fragments from the Earth’s mantle, most notably diamonds.

Pelletal lapilli. Diamond in kimberlite rock, Jwaneng Diamond Mine, Botswana.
Credit: Image courtesy of University of Southampton

Scientists from the University of Southampton have discovered a previously unrecognised volcanic process, similar to one that is used in chocolate manufacturing, which gives important new insights into the dynamics of volcanic eruptions.

Related Articles


The scientists investigated how a process called 'fluidised spray granulation' can occur during kimberlite eruptions to produce well-rounded particles containing fragments from Earth's mantle, most notably diamonds. This physical process is similar to the gas injection and spraying process used to form smooth coatings on confectionary, and layered and delayed-release coatings in the manufacture of pharmaceuticals and fertilisers.

Kimberlite volcanoes are the primary source of diamonds on Earth, and are formed by gas-rich magmas from mantle depths of over 150 km. Kimberlite volcanism involves high-intensity explosive eruptions, forming diverging pipes or 'diatremes', which can be several hundred metres wide and several kilometres deep. A conspicuous and previously mysterious feature of these pipes are 'pelletal lapilli ' -- well-rounded magma coated fragments of rock consisting of an inner 'seed' particle with a complex rim, thought to represent quenched magma.

These pelletal lapilli form by spray granulation when kimberlite magma intrudes into earlier volcaniclastic infill close to the diatreme root zone. Intensive degassing produces a gas jet in which the seed particles are simultaneously fluidised and coated by a spray of low-viscosity melt.

In kimberlites, the occurrence of pelletal lapilli is linked to diamond grade (carats per tonne), size and quality, and therefore has economic as well as academic significance.

Dr Thomas Gernon, Lecturer in Earth Science at the University of Southampton, says: "The origin of pelletal lapilli is important for understanding how magmatic pyroclasts are transported to the surface during explosive eruptions, offering fundamental new insights into eruption dynamics and constraints on vent conditions, notably gas velocity."

"The ability to tightly constrain gas velocities is significant, as it enables estimation of the maximum diamond size transported in the flow. Gas fluidisation and magma-coating processes are also likely to affect the diamond surface properties."

Dr Gernon and colleagues studied two of the world's largest diamond mines in South Africa and Lesotho. In the Letseng pipe in Lesotho, pelletal lapilli have been found in association with concentrations of large diamonds (up to 215 carat), which individually can fetch up to tens of millions of pounds. Knowledge of flow dynamics will inform models of mineral transport, and ultimately could improve resource assessments.

Dr Gernon, who is based at the National Oceanography Centre at Southampton's waterfront campus, says: "This multidisciplinary research, incorporating Earth sciences, chemical and mechanical engineering, provides evidence for fluidised granulation in natural systems which will be of considerable interest to engineers and chemical, pharmaceutical and food scientists who use this process routinely. The scale and complexity of this granulation process is unique, as it has not previously been recognised in natural systems."


Story Source:

The above story is based on materials provided by University of Southampton. Note: Materials may be edited for content and length.


Journal Reference:

  1. T.M. Gernon, R.J. Brown, M.A. Tait, T.K. Hincks. The origin of pelletal lapilli in explosive kimberlite eruptions. Nature Communications, 2012; 3: 832 DOI: 10.1038/ncomms1842

Cite This Page:

University of Southampton. "Chocolate and diamonds: Why volcanoes could be 'a girl's best friend'." ScienceDaily. ScienceDaily, 16 May 2012. <www.sciencedaily.com/releases/2012/05/120516093202.htm>.
University of Southampton. (2012, May 16). Chocolate and diamonds: Why volcanoes could be 'a girl's best friend'. ScienceDaily. Retrieved March 4, 2015 from www.sciencedaily.com/releases/2012/05/120516093202.htm
University of Southampton. "Chocolate and diamonds: Why volcanoes could be 'a girl's best friend'." ScienceDaily. www.sciencedaily.com/releases/2012/05/120516093202.htm (accessed March 4, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Wednesday, March 4, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Tourists Visit Rare Grey Whales in Mexico

Raw: Tourists Visit Rare Grey Whales in Mexico

AP (Mar. 4, 2015) Once nearly extinct, grey whales now migrate in their thousands to Mexico&apos;s Vizcaino reserve in Baja California, in search of warmer waters to mate and give birth. Tourists flock to the reserve to see the whales, measuring up to 49 feet long. (March 4) Video provided by AP
Powered by NewsLook.com
Raw: Injured Miners Treated After Blast

Raw: Injured Miners Treated After Blast

AP (Mar. 4, 2015) An explosion ripped through a coal mine before dawn Wednesday in war-torn eastern Ukraine, killing at least one miner, officials said. Graphic video of injured miners being treated in a Donetsk hospital. (March 4) Video provided by AP
Powered by NewsLook.com
Australian Museum Shares Terrifying Goblin Shark With the World

Australian Museum Shares Terrifying Goblin Shark With the World

Buzz60 (Mar. 4, 2015) The Australian Museum has taken in its fourth-ever goblin shark, a rare fish with an electricity-sensing snout and &apos;alien-like&apos; jaw. Mike Janela (@mikejanela) takes a look. Video provided by Buzz60
Powered by NewsLook.com
Mount Everest Has a Poop Problem

Mount Everest Has a Poop Problem

Buzz60 (Mar. 4, 2015) With no bathrooms to use, climbers of Mount Everest have been leaving human waste on the mountain for years, and it&apos;s becoming a health issue. Mike Janela (@mikejanela) has more. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins