PhD Research Project: NERC CENTA - Volcanic hazards in the Mexico City region: probing a 500,000 ye

Location
United Kingdom
Posted
Nov 30, 2016
Closes
Jan 23, 2017
Organization Type
University and College
Hours
Full Time
Details

The Mexico City region is one of the world’s largest urban areas, and is subject to a range of volcanic hazards, from scoria cone and lava eruptions in the Chichinautzin volcanic field, through to large explosive eruptions of regional stratovolcanoes such as Toluca and Popocatépetl. The exposure of the region to these different volcanic hazards cannot be precisely addressed without a good understanding of past activity. Field exposures across the area are relatively poor, limiting current knowledge to the recent geological past. To improve on this, this project will analyse and interpret a unique tephra record in a 350 m sediment core from Lake Chalco, on the southern edge of Mexico City. The core was collected in 2016 in a project funded through the International Continental Scientific Drilling Program (ICDP). Using fieldwork, dating techniques and the core stratigraphy, this project seeks to determine how the style, frequency and impact of volcanic hazards has varied in the Mexico City region over the past 500,000 years.

The Lake Chalco cores comprise three parallel cores extending to over 350 m beneath the surface, and spanning ~500 ka. Tephra deposits occur throughout the sequence, and include both basaltic and more silicic compositions. The project will work with a composite core splice to produce a complete tephra-stratigraphy for the field site. A major aim of the project is to correlate major deposits with their source volcano, using glass and mineral phase compositions (electron probe and laser-ablation ICP-MS). Alongside this, fieldwork (in collaboration with local geologists) will sample major pyroclastic deposits are more proximal sites, with the aim of correlating them with tephras in the Chalco core. This will provide further constraints on event magnitude and impact, and also the opportunity to obtain better ages (40Ar/39Ar) for these eruptions. The record documented in this way will greatly extend the eruption history of polygenetic volcanoes in the region, and will then be used to explore the nature and impacts of eruptions and their frequency over the lifetime of the regional volcanic systems.

Funding Notes

In addition to completing an online application form, you will also need to complete and submit the CENTA studentship application form available from www.centa.org.uk.

CENTA studentships are for 3.5 years and are funded by the Natural Environment Research Council (NERC). In addition to the full payment of their tuition fees, successful candidates will receive the following financial support.

Annual stipend, set at £14,296 for 2016/17
Research training support grant (RTSG) of £8,000

CENTA students are required to undertake from 45 days training throughout their PhD including a 10 day placement.

References

Arce JL et al. (2013) 40Ar/39Ar dating, geochemistry, and isotopic analyses of the quaternary Chichinautzin volcanic field, south of Mexico City: implications for timing, eruption rate, and distribution of volcanism. Bull Volcanol 75, 774.

Newton AJ, Metcalfe, SE (1999) Tephrochronology of the Toluca Basin, central Mexico. Quaternary Science Reviews 18, 1039-1059.

http://www.icdp-online.org/projects/world/north-and-central-america/lake-chalco-mexidrill/details/#loaded