Further adventures of the EAPSI group! 11 of us ventured over to the island of Java, Indonesia during the holiday weekend of Eid al-Fitr, the celebration of the breaking of fast. After a three hour bus drive, we entered a high-speed boat and sailed over the smooth Indian Ocean towards Krakatoa, a volcano that although from a distance looks small and quaint, boosts the reputation of having the highest growth rates of any volcano in the world (avg. 6.8 meters a year!). Besides its alarming rapid growth, Krakatoa deceives in it's size, as the other 'islands' surrounding its cone actually represent the flanks of it's original, much larger, life, before the catastrophic eruption in 1883.
The 1883 Eruption:
These concepts can also apply to minerals. When a mineral grows in a magma body, its composition resembles that from which it grew, and the conditions under which it grew (temperature, pressure, etc.). When either the magma composition, temperature, or pressure changes, a gradient develops between the mineral and it's surroundings. This causes chemical zonation, similar in some ways to the temperature gradient in a pot during heating water on a stove. Through advancements in microanalytical tools and extensive experimental studies, we now have an idea of how quickly different elements like magnesium, iron, manganese, nickel, hydrogen, etc., diffusive through the crystalline structure of a mineral. With careful application, a scientist attempts to pair timescales of these processes with the physical processes that are occurring within a magmatic system.
Fig 2. On the left is a backscatter electron image of an olivine grain from Volcan Llaima, whereas the right is what this grain looks like in terms of Mg/Fe concentration. The compositional gradient can be easily seen as a color change from the core to the rim, as the olivine is now surrounded by a different compositional external melt.
Last weekend I was fortunate enough to accompany Kendra Lynn, a PhD candidate from the University of Hawaii, on a volcano trek in Indonesia. Two early mornings, two amazing volcanic fields, and two eruptions later, we were both hooked on Indonesian Volcanism. And how could a budding volcanologist not be overwhelmed by the sheer abundance of volcanic centers, plumes, and large number of people living in proximity to it all? This feeling was then clenched by the fact that our trip was sandwiched with multiple airport closures on the nearby islands of Bali and Lombok as Raung roared it's way onto CNN....
This past weekend the EAPSI gang headed over to Pulau Ubin, a small island to the NE of Singapore where you can bike amongst the Mangrove forests, granite quarries, grey herons, and adorable bores. We had an amazing trip, despite the long trek across Singapore (it's bigger than it looks!).
The first few days involved filling out paperwork, but also a beautiful orientation to Singapore. Our adventures took us to the National Museum of Singapore, the beautiful Gardens by the Bay, and an excellent view from the Ministry of Manpower. I think we all feel quite fortunate that we get to spend a summer working, and playing, here in SE Asia.
Volcan Llaima is one of Chile's most active volcanoes, producing a minimum of 54 discrete eruptive events in the last 375 years. A recent surge in geochemical studies of these historical eruptions have provided a solid model to explain the complexities preserved in the eruptive products. This provides us with an excellent starting off point for testing the current model for Volcan Llaima's volcanic storage and conduit system. The goal of this project is to fit timescale information to this detailed petrographic information for samples that currently connect with a larger magmatic framework.
I will mostly be focusing on the 1751 and 1780 eruptions, in not only understanding eruption triggers and the timing between recharge events, mixing, and eruption, but as well as evidence for incomplete evacuation of storage regions or alternative triggering mechanisms.