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Bruce Yardley appointed Chief Geologist

Bruce Yardley (Leeds University) has been appointed Chief Geologist by The Radioactive Waste Management Directorate (RWMD) of the Nuclear Decommissioning Authority (NDA).

Chartership news

Chartership Officer Bill Gaskarth reports on a projected new logo for use by CGeols, advice on applications and company training schemes

Climate Change Statement Addendum

The Society has published an addendum to 'Climate Change: Evidence from the Geological Record' (November 2010) taking account of new research

Cracking up in Lincolnshire

Oliver Pritchard, Stephen Hallett, and Timothy Farewell consider the role of soil science in maintaining the British 'evolved road'

Critical metals

Kathryn Goodenough* on a Society-sponsored hunt for the rare metals that underpin new technologies

Déja vu all over again

As Nina Morgan Discovers, the debate over HS2 is nothing new...

Done proud

Ted Nield hails the new refurbished Council Room as evidence that the Society is growing up

Earth Science Week 2014

Fellows - renew, vote for Council, and volunteer for Earth Science Week 2014!  Also - who is honoured in the Society's Awards and Medals 2014.

Fookes celebrated

Peter Fookes (Imperial College, London) celebrated at Society event in honour of Engineering Group Working Parties and their reports

Geology - poor relation?

When are University Earth Science departments going to shed their outmoded obsession with maths, physics and chemistry?

Nancy Tupholme

Nancy Tupholme, Librarian of the Society and the Royal Society, has died, reports Wendy Cawthorne.

Power, splendour and high camp

Ted Nield reviews the refurbishment of the Council Room, Burlington House

The Sir Archibald Geikie Archive at Haslemere Educational Museum

You can help the Haslemere Educational Museum to identify subjects in Sir Archibald Geikie's amazing field notebook sketches, writes John Betterton.

Top bananas

Who are the top 100 UK practising scientists?  The Science Council knows...

Early dawn sheds light on Vesta

Early dawn sheds light on Vesta

Geoscientist 22.06 July 2012

VestaInitial results of the Dawn mission to Vesta (diameter 530 km) and Ceres (a dwarf planet) have been published 1. Vesta, now visited, has revealed a huge circular 475km diameter negative structure centred on the south pole with a central peak ~23km high (greater than Olympus Mons volcano on Mars!). 

The structure, named Rheasilva (after a vestal virgin), is thought by the authors to be an impact structure and occupies ~80% of the diameter of the asteroid. I regard this as doubtful: firstly, such a huge impact would surely have blown Vesta apart, and I personally doubt whether Mare Imbrium, likely analogous on the Moon, and with no central peak, is an impact structure. I personally think both are more likely to be endogenous structures. 

Picture : False colour map of the south pole of Vesta. -22km is blue to +17 km red to white from mean elevation.

A unique feature is a series of equatorial 10km-wide trough-and-ridge girdles, a completely novel type of structure on a solar system body, and believed to relate to Rheasilva. The asteroid is heavily cratered and there is a multitude of small, fresh bowls, later than the girdles (all likely contemporary) as well as a few older craters. Several of the larger bowl craters have small central craters within.

Vesta 2Picture: The large trough and ridge structures in Vesta’s equatorial region. Image credit, both: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Vesta is widely believed to be a mixture of the HED meteorite types: eucrite (basaltic), diogenite (ultramafic, almost monomineralic with bronzite) and howardite (a brecciated mixture of the two). Radiometric dating has constrained these achondrite meteorites’ differentiation to a few hundred million years after the first condensates of our solar system. These determinations of the likely meteoritic analogues stem mainly from spectrography and geochemical modelling.

The evidence from Dawn indicates that Rheasilva exposes mainly ultramafic rocks, supporting the idea that diogenites form the lower crust. The remainder of the crust seems to be enriched in basaltic rocks and may well expose mainly eucrite and howardite. However, until samples are recovered from the surface, there is no certainty of these attributions, and there may be surprises! Spectrographic determinations do not establish the exact mineralogy and modelling may always miss the mark because of the wrong initial input? At time of writing Dawn is going to go closer to Vesta and obtain close up images, before it moves on to the larger Ceres. Joe McCall


  1. Corrigan, C, Beck, A, McCoy, T 2012 Missions to asteroids: journeying to the beginning of our solar system. Elements 8(1), 9-10.