About us!

The people behind alphaMELTS and the rest of the MELTS family

α alphaMELTS is developed and maintained by Paula Antoshechkina and Paul Asimow at Caltech. The alphaMELTS front-end is a fork of the MELTS software hosted at OFM Research and has benefited from regular source code updates from Mark Ghiorso over the years. The alphaMELTS program includes a number of features not available in the graphical user interfaces (GUI), including the pHMELTS algorithm. The flowchart below is a summary of the current whos, wheres and whats.

The pHMELTS model (A2004) as implemented in alphaMELTS 1.X is based on the MELTS (GS1995) and pMELTS (G2002) algorithms. Rhyolite-MELTS (G2012) includes a modified version of the MELTS calibration, which gives more realistic results for hydrous, silicic magmas (Gualda et al., 2012), and an optional mixed H₂O-CO₂ fluid model (Ghiorso & Gualda, 2015). Rhyolite-MELTS behaves identically to MELTS when quartz and alkali-feldspar are absent; see the MELTS decision tree and explanation of rhyolite-MELTS versions. Various improvements to the core algorithms in rhyolite-MELTS increase the stability of all calculations, including pMELTS ones (see Ghiorso, 2013). The pHMELTS model being implemented in alphaMELTS 2 is based on Rhyolite-MELTS and pMELTS, with a pMELTS+CO₂ model under development (see the alphaMELTS 2 page for more details).

Most of the MELTS-related development at Caltech has been carried out in parallel with Mark Ghiorso at OFM Research / ENKI, but it has included two formal collaborations:

• The first was an ARRA-funded project as part of the xMELTS effort. xMELTS is the next generation MELTS model, which greatly expands the covered range of P-T conditions (see the 7th FAQ on Mark's MELTS homepage). The original NSF awards to Mark Ghiorso, Marc Hirschmann (University of Minnesota), and Tim Grove (MIT) led to the development of the LEPR database (now now LEPR / traceDs) and a provisional silicate liquid model (G2007). The three of us, together with then PhD candidate Emily Hamecher (now at Cal State, Fullerton), then sought to extend and improve the thermodynamic solution models used with xMELTS - specifically garnet and pyroxenes, but also spinel - through grant EAR-0838244. This work is ongoing, and has included incorporating a Bayesian approach to calibration of the equation of state of garnet with ENKI Co-PI Aaron Wolf. Updated solid solution models are being made available at the Supplemental calculator link, as and when they are accepted for publication.
• We are just starting a new project to integrate data resources at EarthChem with the modeling capabilities of the ENKI software framework, as part of NSF's EarthCube initiative. The collaboration will be led by Mark Ghiorso, Kerstin Lehnert (LDEO), and Paula Antoshechkina (through grant ICER-2026819). Caltech involvement in this project came out of the data management component of our calibration efforts, especially pMELTS + CO₂, as well as Paula's participation in ENKI user workshops (see right). In particular, after the Deep Carbon Observatory's Extreme Physics and Chemistry community held a Workshop and Data Hackathon (Arizona State University; November 4-6, 2017), Paula began setting up a mirror of LEPR3 / traceDs, and the DCO/EPC database from OFM Research (LEPR+), with bugfixes, updates to the interface, and new data being added continuously. The LEPR+ database is currently being transferred, and will be hosted by EarthChem while the new web interfaces are developed.

Paula Antoshechkina (née Smith) is an Associate Research Scientist at Caltech. She is responsible for most of the alphaMELTS front-end, forum and website. At the moment she is focused on the the development described in the VERSION 2 tab above, and adding CO₂ to the pMELTS model. She is part of the Magma Chamber Simulator group (see the LINKS tab) and also working with ENKI (see below); her other research interests are described elsewhere on the MAGMA website.

Paul Asimow is Professor of Geology and Geochemistry at Caltech. He developed pHMELTS and many of the tools since incorporated into alphaMELTS. He is PhD advisor to Caltech grad students working on the pMELTS+CO₂ model, and amphibole calibration. He is also involved in shock-wave experiments and theoretical calculations on silicate liquid and minerals.

Mark Ghiorso is the Vice-President of and Senior Research Associate at OFM Research. As well as ENKI (see below) and xMELTS-related development, his current areas of work include modeling H₂O-CO₂ fluids, thermodynamics of hydrous silicic systems and visualization of equilibrium phase relations.

ENKI is a web-based, community-driven, model configuration and testing portal that provides tools in computational thermodynamics and fluid dynamics. Several types of calculations can be performed online on the ENKI Cloud Server, with no need to install anything on your computer! There is also the GitLab ENKI code and documentation repository. Read more on the ENKI User Projects page for a (somewhat out of date) description of how alphaMELTS and other MAGMA@Caltech tools fit in with the ENKI project.

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More Links

• MELTS Facebook Page
• alphaMELTS GitList
• PhasePlot download
• Supplemental calculator

Documentation

• HTML (v1.4; 18 Jul '14)
• PDF (v1.9; 27 Aug '18)
• MELTS camp presentations
• Forum FAQ

EXAMPLES

• DACITE (coming soon)
• MELTS camp exercises
• Forum tutorials