We are soliciting applications for a two-year postdoctoral position that will play a central role in our NSF-funded project on “Sulfur Isotope Systematics and Oxygen Fugacity Evolution in the 1257 CE Samalas Magma Reservoir, Indonesia” (see project abstract below). The selected postdoctoral scholar will be based at Queens College of the City University of New York (primary supervisors Marc-Antoine Longpré at CUNY and Adrian Fiege at the American Museum of Natural History) for year 1 and at Southern Methodist University (primary supervisor Rita Economos) for year 2. The project will be conducted in close collaboration with Céline Vidal (University of Cambridge), IPGP (France) and CVGHM (Indonesia). The postdoc’s responsibilities will include XANES, FT-IR, EPMA, and SIMS data collection and interpretation, as well as preparation of manuscripts for peer-reviewed publication.
A PhD in Earth Science or a related sub-discipline, with specialization in petrology/geochemistry, is required. Experience with melt inclusion analysis and microbeam analytical methods (e.g., EPMA, FT-IR, SIMS, LA-ICP-MS or XANES) is preferred. The start date is as soon as September 1st. We will begin considering applications on June 30th, but will accept applications until the position is filled. Applicants should send a motivation letter (1-2 pages) that includes applicable research experience, a CV with publication list, and contact information for at least two references as a single PDF document to Marc-Antoine Longpré (firstname.lastname@example.org).
Sulfur is the third most abundant volatile element in volcanic systems following water and CO2. Release of sulfur to the atmosphere during volcanic eruptions can perturb climate on a global scale and cause acid rain, resulting in significant environmental impact. The eruption of Mt. Samalas on Lombok Island, Indonesia, in 1257 CE generated the largest volcanic sulfur emission event of the last 2000 years. This event is coincident with a multi-year global cooling event around the beginning of the “Little Ice Age”. The central research question of this project is: how did this volcano build up so much eruptible sulfur? The scientist participants will test hypotheses of sulfur enrichment mechanisms by probing deep into sulfur’s properties and behavior within sulfides, apatites, and volcanic glasses (rapidly cooled melts) from pumice samples from this eruption. The project will utilize the most advanced analytical techniques to investigate sulfur chemistry, many of which were developed recently by participants on the research team. This project will yield new insights into the capability of magmatic systems beneath volcanoes to accumulate reservoirs of eruptible sulfur large enough to create significant global environmental impacts.
The project exploits the complex geochemical behavior of sulfur to track its movement from the liquid phase (silicate melt) into solid (mineral) and gas phases in magmatic systems. Sulfur is a polyvalent element that can change its valence state from S2- to S6+ over a narrow redox range relevant for terrestrial magmatic systems. This makes sulfur an excellent tracer for changes in magma redox conditions that may have played a critical role in the transport, enrichment, and release of sulfur during the 1257 Mt. Samalas eruption. The involved magmatic processes (e.g., degassing) should lead to predictable fractionations of sulfur isotopes in glasses and minerals, which will further constrain the dynamics of sulfur build-up at Samalas. The valence states of sulfur in minerals and glasses will be determined via X-ray absorption near-edge structure (XANES) spectroscopy, whereas sulfur isotope ratios will be measured by secondary ionization mass spectrometry (SIMS). This dovetailing of redox and isotope studies is a powerful new approach to addressing sulfur-related science questions. This project will serve as a blueprint for future studies of other volcanic systems and will have implications for magmatic sulfide ore-forming processes and crustal magma evolution of interest to the broader earth science community.