Monthly Favourite Meteorite (NWA 5507)

Northwest Africa 5507 (NWA 5507)

Northwest Africa 5507 was discovered in the Sahara desert in Northwest Africa during 2008 in the form of 2.5kgs of whole stones and fragments. Some of the stones were 95%+ covered in fresh fusion crust while the fragments were somewhat patchy. The stones were classified as a rare primitive Ordinary Chondrite L3.2 with a Shock Rating of S2 and a low Weathering Level of W1.

NWA 5507 is one of the more visually striking primitive ordinary chondrites found during the NWA rush. It is characterised by a multitude of various sized and coloured chondrules set in a very dark matrix. One of the more unusual features of this meteorite, is the apparent orientation of chondrules. Many of them are elongated to a slight oval shape which all appear to be arranged in the same direction. Some stones and slices show this more than others however the second photo below depicts this very well. One study (Matrin et al, 1980) has suggested this occurred during compaction in the meteorite parent body. Another feature of this meteorite is the common occurrence of Troilite (FeS) nodules and chondrules armoured with this same material. The nodules often appear quite large in size and can have a very unusual shape. The complete slices below are part of the Meteorites Australia Collection.

5.99g Complete Slice - MA.10.0011

NWA 5507 (L3.2) - 5.99g Complete Slice
Enlargement ---> 2000 x 1861 (1.04MB)

NWA 5507 (L3.2) - 5.99g Complete Slice
NWA 5507 (L3.2) - 5.99g Complete Slice
Enlargement ---> 2000 x 1819 (0.98MB)

NWA 5507 (L3.2) - 5.99g Complete Slice
Slice showing crusted edge and crust variance with the large white chondrule at front left.
Enlargement ---> 1500 x 1113 (278KB)

8.72g Complete Slice - MA.09.0011

NWA 5507 (L3.2) - 8.72g Complete Slice
NWA 5507 (L3.2) - 8.72g Complete Slice
Enlargement ---> 2000 x 1673 (0.98MB)

NWA 5507 (L3.2) - 8.72g Complete Slice
NWA 5507 (L3.2) - 8.72g Complete Slice
Enlargement ---> 2000 x 1717 (941KB)

9.22g Complete Slice - MA.09.0011

NWA 5507 (L3.2) - 9.22g Complete Slice
NWA 5507 (L3.2) - 9.22g Complete Slice
Enlargement ---> 2000 x 1685 (1.05MB)

NWA 5507 (L3.2) - 9.22g Complete Slice
NWA 5507 (L3.2) - 9.22g Complete Slice
Enlargement ---> 2000 x 1632 (1.01MB)

NWA 5507 (L3.2) - 9.22g Complete Slice
NWA 5507 (L3.2) - 9.22g Complete Slice with large irregularly shaped Troilite nodule.

NWA 5507 (L3.2) Stones & Fragments

NWA 5507 (L3.2) Group
NWA 5507 (L3.2) Group - Copyright © Marcin Cimala.
Enlargement ---> 1500 x 1125 (290KB)

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