Seymchan

Seymchan was initially discovered in June, 1967 by the geologist, F. A. Mednikov during a geological survey. He found a regmaglypted, triangular-shaped mass weighing 272.3 kg lying in a stream bed that flowed into the Hekandue River which is a tributary of the Jusachnaja River in the Magadan District, Russia. Later in October of that year another mass weighing 51kg was discovered by I. H. Markov just 20m from the initial find using a mine detector. Recent expeditions from 2004-2006 have yielded many more masses totalling several tonnes.

Seymchan has a somewhat unusual history as it was initially classified in 1974 as a rare IIE iron meteorite. However, after further studies more than a decade later it was found that this meteorite yielded results that deviated significantly from the usual IIE iron results. So it was reclassified as an Ungrouped Iron. This was not the final classification as the more recent 2004 finds consisted of meteorites with silicates in the form of olivine crystals. This interesting discovery in the new specimens quickly led to Seymchan being reclassified again as a main group Pallasite. The new specimens vary widely in their appearance with some being completely siderite (iron) while others areas of the meteorite are nearly all silicate (stony material) with a small amount of iron between the olivine. Others are a mix of both and can also show distinct boundaries between siderite and silicate areas. The 219g and 175g slice below is an example of this. These specimens are part of the Meteorites Australia Collection.

Seymchan (Pallasite) - 219g Etched Slice.
Enlargement ---> 1500 x 1447 (576KB)

Seymchan (Pallasite) - 219g Etched Slice.
Enlargement ---> 1500 x 1434 (600KB)

Seymchan (Pallasite) - 175g Etched Slice.
Enlargement ---> 1500 x 1410 (521KB)

Seymchan (Pallasite) - 175g Etched Slice.
Enlargement ---> 1500 x 1415 (534KB)

Seymchan (Pallasite) - 43.0g Oriented Individual (Leading Side).

Seymchan (Pallasite) - 43.0g Oriented Individual (Trailing Side).

Seymchan (Pallasite) - 15.50g Complete Slice.