The High Possil Meteorite

Published on: Author: thehunterianblog 1 Comment

A student post from Hayley Lowe, Postgraduate Researcher in Geography and Earth Sciences at the University of Glasgow.

On the morning of April 5th 1804, Glasgow was alerted to the sounds of a series of loud bangs, heard as far away as Falkirk. To the amazement of the locals, these noises were accompanied with a fireball falling from the sky which came to land in Possil quarry (now Possil Marsh). The quarrymen who witnessed this fall described a hole 18 inches deep and 15 inches wide, and at the bottom of this hole sat a rock. This rock is now known as the High Possil meteorite and is the first meteorite known to have hit Scotland.

The High Possil Meteorite, GLAHM:M172.
The High Possil meteorite, GLAHM:M172.

Initially, the fragments were assumed to be dolerite, which is a local rock, so they were discarded as unimportant. However, at the time the quarrymen did not know that this rather unextraordinary looking rock represents some of the very first material to be formed from the gas and dust surrounding the sun as it was being born. The High Possil meteorite has been dated through geochemical techniques, and it is 4 and a half billion years old. In comparison, the oldest rocks on Earth currently have been dated at 4.2 billion years old.

Luckily, the story of this object hitting the ground from the sky reached the ears of some local scientists. They immediately realised that this rock was unlikely to be dolerite as suspected, and they were able to retrieve some of the fragments of the rock. Unfortunately, only around 380g was recovered but 4.5kg is thought to have fallen. The largest fragment remained in the possession of Robert Crawford, who was the owner of the quarry, until his death in 1810 when his widow generously donated the fragment to the Hunterian Museum where it remains today.

Today the High Possil meteorite is classified as an L6 ordinary chondrite. An ordinary chondrite means that this is very old, and unaltered containing things called chondrules. Chondrules are spherical droplets of material that was molten during the early solar system, and these are thought to be the building blocks of all rocky material seen today. L refers to the low iron content within the rock and the 6 indicates that the chondrules are relatively indistinct. L chondrites are amongst the most common meteorites to fall to the Earth, and are thought to come from a group of asteroids in the asteroid belt known as the Flora group. This group has been speculated to be the origin of the asteroid that caused the dinosaur extinction, but this has not been proven.

Everything we now know about meteorites stems from the day the High Possil meteorite caused alarm to Glasgow. That impact has since been hailed as the start of meteorite science, and was the first meteorite impact witnessed in Scotland. Whilst the sample itself is safely within the Hunterian Museum, and other scientific institutes, a memorial stone has been placed in the Possil Marsh Wildlife Reserve which commemorates the events of the 5th April 1804.

Sources:

Remembering the day Glasgow was struck by a meteorite, Glasgow Live, 26 November 2020.

Eye Spy Glasgow: The ‘violent whizz’ of the rock that fell to earth…in Possil, Evening Times, 22 August 2013.

Bevan, A.W.R., Hutchison, R., Easton, A.J., Durant, G.P. and Farrow, C.M., 1985. High Possil and Strathmore-A study of two L6 chondrites. Meteoritics20(3), pp.491-501.

Vokrouhlický, D., Bottke, W.F. and Nesvorný, D., 2017. Forming the Flora family: Implications for the near-Earth asteroid population and large terrestrial planet impactors. The Astronomical Journal153(4), p.172.

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