Meteorites provide us with invaluable material evidence of how the Solar System formed and evolved through time. In particular, iron-based meteorites provide material originating from the complex planetary bodies, providing insights to the number, diversity, evolution and destruction of protoplanets that existed in the early Solar System. Knowledge of this helps us understand how objects are related to one another and to investigate the chemical heterogeneity of the solar nebula from which all planetary bodies originate.
To continue advancements in our understanding of the Solar System, large numbers of all classes of meteorite must be recovered and analysed. The most prosperous places to find meteorites is Antarctica, which have contributed over 66% of the world’s classified meteorite samples. This large proportion is due to Antarctica’s ice dynamics, which produce highly concentrated and local Meteorite Stranding Zones (MSZs). Yet the inherent complexities of visiting the Antarctic MSZs means collection missions are few (around one or two a year, with no UK missions to date). And crucially, a have followed similar collection protocols, focusing their search efforts upon finding material located on the ice surface. The consequence of this surface search approach appears to have been an under representation of iron-based meteorites in the world’s body of curated samples: 0.7% from Antarctica compared to 5.5% from the rest of the world.
Recent laboratory and mathematical modelling work by a team at the University of Manchester (published in Nature Communications) have hypothesised that missing iron meteorites are likely to lie hidden a few centimetres below the surface out of sight of surface searches. We proposed that this under-representation of iron-based meteorites might be the result of the Sun’s rays penetrating the clear ice in MSZs during the summer months and warming the iron-rich rocks more than non-metallic rocks. This ice melting process allows the more iron-rich meteorites to effectively sink into the upwelling ice, meaning that they don’t easily emerge onto the surface to be spotted by collection teams. This means that there may be a sparse layer of iron-rich meteorites trapped buried at depths of ~30-50 cm in the Antarctic ice.
Definitive proof of the existence of this layer will help close this mystery, and simultaneously open up many other exciting scientific opportunities.
The ‘Lost Meteorites of Antarctica Project‘ is funded by the Leverhulme Trust with support from the British Antarctic Survey to explore new Meteorite Stranding Zones in Antarctica for meteorites that are encapsulated in ice. The exploration activity involves several steps:
- Investigate ice flow regimes in Antarctica to pinpoint suitable exploration sites
- Develop more sophisticated models to predict burial depths of different meteorite types in different field settings
- Developing technology to identify ice trapped meteorites
- test and tune technology to understand sensitivities to different meteorite grps
- ruggidise technology by testing in field settings (Svalbard and Antarctica)
- Collect surface located meteorites to determine productiveness of field settings
- a reconnaissance fieldtrip will take place in December 2018
- Collect sub-surface meteorites to test our Lost Meteorites of Antarctica hypothesis
- a full team fieldtrip will take place in December 2019
- Classify returned meteorites and make them available for research by the scientific community