Katie Joy, South Graves Icefield, 22nd December 2012
Hello world
Hope that you are all still there as I think yesterday was earmarked to be the end of the world according to the Mayans. I didn’t put it my diary though so not sure if the date has passed or not. I should really remember to bookmark these sorts of events. Anyway, if the end of the world happened here in the Graves Icefields we are about as far from a burning hell you can get… it is a freezing -25degC + extra windchill and the katabatic wind is absolutely howling outside at about 40 knots blowing in from the south. It has got a lot worse than when Tomoko uploaded the blog from yesterday (see photo), and we are in a complete white out with snow being whipped along the ground and gusts of winds that could knock you off your feet. There is no blue sky or Sun to be seen. I wish could post a photo of today’s epic scene, but to be honest it would look like a white sheet of paper. From our tent entrance we can no longer see the poo tent clearly, and the snowmobiles, which have been parked a bit further away to stop them from being covered in the drifting snow, are completely lost in the icy mist. I ventured out this morning to tighten up our tent’s guy ropes and visit the ladies room, and came back looking like a walking snowwoman. Tomoko had to de-ice me. The tent is creaking, groaning and flapping around like a wild animal wanting to be set free. This is the real Antarctica, and it is pretty exciting and incredible noisy. Thank goodness for our nice warm propane stove and thick sleeping bags that are keeping us cosy and warm. We will be staying inside all day, and are keeping our fingers crossed that the wind will drop soon. We hope that the systematic team are having better weather and are out gathering lots of good meteorites.
As there is little to report on our searching efforts, I thought that instead I would talk briefly about some of the meteorites that I am really hoping we find over the coming week, and the ones that I study in the lab – those that have come here from the Moon. Lunar meteorites are fragments of rock that were thrown off the Moon when it was struck by asteroid or comet debris (i.e., in an impact event), and then entered an Earth crossing orbit. Like other types of meteorites they have an exterior fusion crust generated when the rock enters through the Earth’s atmosphere and, as such, we can identify them as being extra-terrestrial in origin. We further recognise them as being from the Moon as they have a similar chemistry, mineralogy, age and noble gas content to samples returned by the Apollo (USA) and Luna (Soviet Union) missions.
Lunar meteorites have been found in Antarctica, Oman, the deserts of North West Africa, and a few from deserts in Australia and Botswana. These are very rare meteorite samples compared to most types that are collected. To date, there have been ~150 individual (named) lunar meteorite stones found, collectively weighing ~61 kg (~16% of the mass returned by the Apollo and Luna missions). Some of the samples are fragments of volcanic lavas (known as mare basalts) and others are from the Moon’s white highlands. We do not know the exact location where they were launched from the lunar surface, but it is thought that they represent a random sampling of lunar rocks. This is their key scientific importance: in contrast to the Apollo and Luna mission samples, which were all returned from the central and eastern regions of the nearside of the Moon, lunar meteorites represent global geological sampling of our nearest neighbour. Therefore, studies of these important meteorites are helping to advance lunar science by providing new insights to the Moon’s geological diversity and history.
For more information, and a full list of lunar meteorites please see the NASA Meteorite Curator’s Lunar Meteorite Compendium at http://www-curator.jsc.nasa.gov/curator/..%5Cantmet/lmc/index.cfm and Randy Korotev’s Lunar Meteorite list at http://meteorites.wustl.edu/lunar/moon_meteorites_list_alumina.htm . Hopefully we will be able to add a few more to these numbers this season if the weather improves!
PS – ANSMET 2011 team – I am very much hoping that our sledges and flags haven’t been drifted in like last year… remember the fun that was had digging them out at Miller Range camp 2! Attached is a picture of the snow drifts in camp yesterday and we will have to wait until the storm abates to see what the situation is like outside…
Nice drifts!