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Gavin Tolometti

Craters of the Moon...More Thin Sections + ISU Samples


Right now, let us begin.

The thin sections I submitted in mid-June have been completed and I collected them from the lab. I recently realized afterwards that I am short six Idaho State University thin section samples. I have emailed Steve (thin section specialist at Western University) to see if he is still mounting the samples. I have taken images of the thin sections and will be conducting detailed petrographic analysis in the coming two weeks before travelling to Idaho. A preview of 5 samples are below, two of which are Idaho State University samples.

The image (plane-polarized light) is an Idaho State University Highway Flow sample from Craters of the Moon. The three highway flow samples analysed from my 2016 field season show very little crystal texture or well-preserved minerals. The sample above would have been taken below the surface of the lava flow, away from superficial weathering and iron oxide coating.

The image (plane-polarized light) is an Idaho State University North Crater sample from Craters of the Moon. The volcanic texture is similar to the trachylite patterns observed in the North Crater samples collected by myself and Team Canada. The plagioclase crystals are elongate, have a slight preferred orientation, and are encased in a black basaltic glass.

The image (plane-polarized light) above is a Devil's Orchard sample from Craters of the Moon. The plagioclase crystals are orientated in respect to the lava flow direction. Plagioclase, fayalite, and augite phenocrysts are surrounded by the elongate plagioclase, and all of the minerals are encased in a black basaltic glass. Unlike the other Devil's Orchard samples analysed, the plagioclase crystals are coarser.

An image (plane-polarized light) of a Highway Flow sample from Craters of the Moon shows little mineralogy and crystalline textures. The entire thin section comprises of a dark brown glass formed from rapid cooling of the lava as it moved across the surface. Few minerals identified are fayalite, augite, and plagioclase. It appears without breaking a vast amount of Highway Flow's surface during sampling, the petrographic properties of the lava flow are difficult to analyse.

A cross-polarized light image of Devil's Orchard from Craters of the Moon. The plagioclase crystals are slightly orientated and high birefringent fayalite and augite and scattered across the sample. The vesicles are deformed, stretched by the movement of the lava whilst it was still hot. Gas would have still been entrapped as the flow was moving away from its source.

I will be taking the images with me to the field to show Dr Shannon Kobs Nawotniak and Dr Scott Hughes. There opinions on their samples would be helpful when writing up my thesis. Something that was discussed during one of the FINESSE telecons was Scott taking Alex and a couple of other people out towards Serrate Flow. This is convenient because part of my field work includes collecting Serrate samples further from its contact with Blue Dragon and Devil's Orchard (further NE from where we reached last field season in 2016).

Recent work for me has been the submission of my Leverhulme article for their next newsletter. My article summarises my research in laymens terms so the organization, their supporters, colleagues, and the public can understand what I am trying to achieve for my MSc thesis. They will get back to me when they know which newsletter my article we be incorporated in. On the subject of the Leverhulme Trust, I will need to start planning my report for them. The report has to discuss my intensions for my research for the year I am funded. What I plan to achieve, how I will and/or have achieved it, why, and what are some findings or conclusions I have made. It has to be submitted 6 weeks after my scholarship officially begins on the 1st of August.

I talked to Oz (Dr Gordon Osinski) about my XRF issue and he has subjected I send my samples to ALS laboratory in Sudbury. Eric has sent me the details and I can look into how much it will cost to run my samples for major elemental data. I plan to have this resolved before I head out into the field.


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