Question: Have you ever discovered a new fossil or rock, that was yet to be discovered?

Natasha Dowey answered on 4 Mar 2019:

Kind of!
During my PhD I studied the rocks formed by an explosive volcanic eruption. Scientists had looked at them before, but only down at the coast of Tenerife- they hadn’t looked at them in the high-altitude desert near the top of the volcano. I was working up there, and I found a valley that contained some really cool rocks, that no one had previously described.
The rocks were huge boulders of pumice, which is a bubbly volcanic rock, that were thrown from the volcanic vent during the final stages of the eruption- they were probably erupted during the collapse of a caldera (a large bowl shape that forms during some volcanic eruptions when all the magma is emptied from the chamber, causing it to collapse and drop down).
These large boulders were black in colour, telling me they were of a different chemistry to the surrounding creamy-white rocks, and some had green streaks within them. When I took them back to the lab to analyse them, I found that the black and green colours were two different types of magma, that had been “mingled” together in the chamber. Both of these types of magma were different to the more silica-rich magma that made up most of the eruption.
I interpreted these rocks to mean that at the bottom of the magma chamber system within the crust, there were remnants of other batches of hotter, more iron-rich magma. These hotter batches of magma may have triggered the eruption to occur, by moving up into the chamber system and mixing with the cooler magma stored there. I’ve attached some photos with my field assistant John for scale. The day when I found this valley was one of the best of my PhD- it was so exciting coming across something that no one had ever described before!