Three-dimensional texture of cluster chondrites

The majority of meteorites, the so-called chondrites, predominantly consist of millimeter-sized beads (chondrules) which represent solidified droplets of silicate magma. The formation of these chondrules is highly debated and the time interval between chondrule formation and accretion of the first chondritic rocks is poorly constrained. The investigation of specific textural units in ordinary chondrites shall help to better understand the chondrule forming process and to narrow this time interval. These textural units are characterized by clustering of deformed chondrules (termed „cluster chondrites“ by me)  and can be interpreted in a way that hot and deformable chondrules accreted to form a solid rock only hours to a few days after chondrule formation. This is in strong contrast to the current view, that chondrules were already cold and solidified at the time of parent body accretion.

The three-dimensional texture of cluster chondrite fragments was documented by different methods in the shape of image sequences.

µ-CT of a cluster chondrite

Micro-3D-Xray-computed tomography of a cluster chondrite clast in the chondritic meteorite NWA 5205. The width of field is 2 cm.

These results were provided by Dr. Dominik Hezel, Institut für Geologie und Mineralogie, Universität zu Köln.

Micro-grinding technique

In order to visualize the three-dimensional texture a square column of a cluster chondrite clast from NWA 5205 was successively grinded in 120 steps of 80 µm each (see figure) and documented in the shape of an image sequence (see movie). This work was performed in cooperation with Mrs. Ursula Heitmann, preparator at the Institut für Planetologie, Münster.

Figure: