EAG News
Goldschmidt2018 is family friendly!
If your family is accompanying you to Goldschmidt2018, the conference warmly welcomes them. New this year, child care is available for the children of delegates (reservations required to guarantee space). Learn more.
2018 Outreach Program to Africa: AFIPS Call for Workshops now open
As part of the 2018 Outreach Program to Africa, the EAG and the Geochemical Society are co-sponsoring the Africa Initiative for Planetary and Space Sciences. As part of this initiative, two 4-day workshops, aimed at strengthening the African vision for developing Planetary and Space Sciences at the local, national, or regional scale, will be organised in 2018. Find out more.
The call for workshops is now open. Deadline for submission of proposals: 1 June 2018.
Distinguished Lecture Tour 2018
Dr. Jim McQuaid (University of Leeds) has been selected as the EAG 2018 Distinguished Lecturer. His research is primarily focused upon observations of the composition of both gas phase and aerosol species in the atmosphere, and an exciting series of lectures on these themes has been proposed for this year’s Lecture Tour.
If your institution is based in Central or Eastern Europe and you wish to invite Dr. McQuaid to present one or two lectures, please contact us. More details.
EAG Latest Publications
Colloidal origin of microbands in banded iron formations
M.S. Egglseder, A.R. Cruden, A.G. Tomkins, S.A. Wilson, A.D. Langendam
Precambrian banded iron formations record the composition of Earth’s atmosphere and hydrosphere during the global rise of oxygen. It has been suggested that the banded texture of these rocks points to fluctuations in ocean chemistry although this remains a subject of debate. […]
Silicon and oxygen isotopes unravel quartz formation processes in the Icelandic crust
B.I. Kleine, A. Stefánsson, S.A. Halldórsson, M.J. Whitehouse, K. Jónasson
Quartz formation processes in the Icelandic crust were assessed using coupled δ18O and δ30Si systematics of silica deposits formed over a wide temperature range (<150 to >550 °C). Magmatic quartz reveals δ18O (-5.6 to +6.6 ‰) and δ30Si (-0.4 ± 0.2 ‰) values representative of mantle- and crustally-derived melts in Iceland. […]
Comment on “Ultra-high pressure and ultra-reduced minerals in ophiolites may form by lightning strikes”
W.L. Griffin, D. Howell, J.M. Gonzalez-Jimenez, Q. Xiong, S.Y. O’Reilly
Ballhaus et al. (2017) use electric-discharge experiments to argue that lightning strikes could produce ultra-high pressure (UHP) and super-reduced (SuR) phases “identical to those found in ‘high-pressure’ ophiolites” and that thus there is “not sufficient evidence to challenge long-established models of ophiolite genesis”, specifically for the UHP processing of Tibetan ophiolites. However, the authors produced no evidence for UHP phases in their experiments. […]
Reply to Comment on “Ultra-high pressure and ultra-reduced minerals in ophiolites may form by lightning strikes”
C. Ballhaus, R.O.C. Fonseca, A. Bragagni
Griffin et al. (2018) discard our lightning experiments because we did not identify ultra-high pressure (UHP) phases. Our experiments (Ballhaus et al., 2017) provide the first rational explanation of many unusual findings in the so-called UHP ophiolites and hence undermine the foundations on which the resulting speculative geotectonic scenarios are based. […]
Glacier Biogeochemistry
Martin Sharp, Martyn Tranter
This issue of Geochemical Perspectives charts a paradigm shift in glacier geochemistry and hydrochemistry. The beds of glaciers and ice sheets were thought to be abiotic only 20 years ago, but now it is known that a diverse range of microbes colonise these environments, and that microbial processes influence chemical weathering and nutrient cycling in aqueous subglacial environments.
