IMCA Insights – January 2012
Meteorite Men, the Morasko Episode -
Science after Filming
by Andrzej S. Pilski

The final scene of the Morasko episode shows Geoff Notkin and Steve Arnold loading their precious find into their car. A happy ending?

It is not a surprise that a movie is not like real life. The hunting was done in the Morasko preserve area with special permission, which did not allow finds to be removed from the preserve. The only exception made was for scientific research in the Institute of Geology of the Adam Mickiewicz University in Poznań, Poland. So when the cameras were turned off, Geoff and Steve’s the find was unloaded and went into the car of Professor Muszyński. Bad for the finders, but good for science.

34kg Morasko

The 34 kg Morasko weathered iron found by Steve Arnold.
Size: 28x24x18 cm.

It is well known that scientists owe many of their meteorites used for research to private meteorite hunters. Sadly, it is known that many meteorites do not come with all of the potentially valuable information related to their discovery and subsequent handling: type of soil where found, depth of discovery, if and how it was cleaned, etc. I guess if the Meteorite Men could have taken their find with them, it would have been cleaned, cut and etched for display and sale. Some important information might have been lost to scientific research.

Professor Muszyński let me clean and cut the specimen for research. Does this sound the same as Geoff and Steve would do? Maybe, but I did my work for Professor Karwowski, who is an experienced researcher of secondary weathering minerals. All the material removed from the surface of the find was sent to him, and the results were surprising.

Weathering minerals in Morasko

Secondary weathering minerals after removing an endpiece from the
upper right of the iron from the previous image.

It seemed to me that the find was not very weathered, so I started with chipping out the clay to uncover the iron metal. Surprisingly, a quite large endpiece came out, uncovering a dark, wet substance with elongated shiny inclusions. I tried on another side, where the darker surface suggested an iron oxide on metal. Instead, I uncovered a gray mineral with rather good cleavage and no metal again. So I decided to cut an endpiece off, to see, how deep the weathering went into the meteorite and how much metal was left inside.

Etched section of Morasko

Etched cross section of the 34 kg find. There are many cohenite
inclusions in the lower part and two schreibersite inclusions
elongated horizontally below center; the lower one is rimmed
 with cohenite. A part of a troilite inclusion with schreibersite
rim is seen at the upper edge. At right, between iron and
clay, dark iron hydroxides are visible with cohenite inclusions.

It can be seen that some areas are much more affected by weathering than others. To the right of center, one can see a sharp border between metal and, cemented with brown iron hydroxides, clay. The same may be seen on the opposite side. But slightly lower on the right side and higher on the left side weathering went deeper into the meteorite, turning kamacite into black iron hydroxide and leaving only cohenite on the right side.

Chukanovite

A microdruse of chukanovite in the 34 kg Morasko iron.
(Photo by Ł. Karwowski)

The gray mineral with good cleavage mentioned earlier turned out to be the greatest discovery in the iron. It is a simple, but rare hydroxide-carbonate mineral of iron, unstable under normal atmospheric conditions. It was first discovered in the Dronino iron and named chukanovite in honor of the well-known Russian mineralogist. Morasko is the second meteorite in which this mineral was found. And this discovery would not have been possible if the find had been normally cleaned for collectors who would have removed all of the rust shell as a waste material.

Etched half of 544g Morasko

A half specimen of 544 g Morasko shrapnel.
Widmanstätten pattern is slightly distorted because of shock.

During filming I was kept aside so as not to be seen by the camera. But earlier, during scouting before filming, I had the privilege to be Geoff’s partner in hunting and I was lucky enough to find another Morasko specimen totally different from the big one. Steve’s find was individual, found deep in clay and strongly weathered. My find was shrapnel found at a shallow depth among stones and gravel and only weakly weathered. Both finds together are evidence that weathering grade tells us more about conditions in the ground than about terrestrial age, which is obviously the same for both finds.

Digging out the 34kg Morasko

Digging out the 34 kg Morasko iron.

Morasko finds are strewn very densely in a relatively small area on the northern slope of a terminal moraine left after the last glaciation. This gave reason for a supposition, that the iron could shower on a glacier and then be deposited on the moraine. However, the large iron was found embedded in the 2 million year old colorful Poznań clay, which means it had to penetrate the soil instead of being deposited. Unfortunately, the tight schedule of filming and poor weather left no time for examining the excavation in search of traces of a hole made by the iron penetrating the ground.

There is no doubt that it is better to recover a meteorite, even with some loss of scientific data, than to let it rust in the ground. I would be happier, however, if meteorite hunters would keep in mind that data concerning the circumstances of their finds may sometimes be of greater importance than the finds themselves.

This article has been compiled and edited by Anne Black and Norbert Classen

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