JMDMT #1815 Microfossils of Cyanobacteria in Carbonaceous Meteorites

The James M. DuPont Meteorite Collection - matrix of plagioclase. However, in large scale, the remnant of the original pyroxene and plagioclase crystals can be recognized. A noteworthy feature is that the pyroxene crystals (up to 1 mm long) reveal coase herrin-bone exsolution textures with thick (up to 35 micrometers) exsolution lamellae of augite on (001). The presence of (100) exsolution in the low-Ca host phase and straight extinction indicate that the pigeonite is inverted to orthopyroxene. In the ajacent area, high-Ca pyroxene with fine exsolution on (001) (up to 0.8 x 0.5 mm in size) are often found, which may be a rim of originally zoned pyroxene in Ca-Mg-Fe contents. The slow cooling texture of such pyroxene is close to that of inverted pigeonites (cooling rate 0.00016 degrees C/yr) in the