Simon Drake and Andy Beard, in a recent article (pp. 10-15) in The Geoscientist of the GSL, recent fieldwork on the Isle of Skye has led to the discovery of the extraterrestrially derived mineral vanadium-rich Osbornite (TiVN) within a one-metre thick layer at two separate sites seven kilometres apart. How had this layer been deposited? One site was right under the earliest Paleocene basalts on the Island; could there have been a meteorite impact before the first volcanic activity on Skye? Did the meteorite cause the volcanism? Where did this layer fit into a short lived (60-55Ma) volcanic episode on Skye?
To date, this mineral had only been reported as dust collected from the wake of the Wild II comet trail during the 2006 NASA Stardust mission. It had never been reported on Earth before, and therefore could prove an extremely important and interesting find. The story began in 2011 during PhD fieldwork when I was trying to identify silicic ignimbrites on Skye and from there to map and log these deposits.
The idea was then to correlate the logs and determine the nature and characteristics of eruptions. From there, I wanted to establish precisely where silicic volcanics fitted into Skye’s volcanological evolution. I first needed to check the earliest volcanic rocks on the Island, and began mapping with ‘ignimbrite’ eyes on. During this fieldwork, I decided to target the lavas on the Strathaird Peninsula near Torrin and look right at the base. My colleague Andy Beard and I traversed some very awkward ground and located a 1 meter thick layer of extremely strange looking rock beneath these lavas. The rock was buff-coloured and had a streaky fabric, akin to a welded ignimbrite.
I’ll refer to it as a meteoritic ejecta deposit (Site 1).
The layer is housed in a pronounced, recessed notch at the base of the An Carnach lava pile on the Strathaird Peninsula. A later sill has chilled between the lowermost part of the meteoritic deposit in the notch and the uppermost Mid-Jurassic sedimentary rocks. By stripping the sill out of the stratigraphy it became clear that the ejecta deposit
layer was initially lying on top of Mid-Jurassic sedimentary rocks.
Managed & Built by I2M Consulting, LLC | © 2010-
