English: Calciocarbonatite lapillistone from the Miocene of Germany.

The German rock seen here is famous among carbonatite researchers. It comes from the first ancient carbonatite unit ever demonstrated to have originally been surficial volcanic material (i.e., an igneous rock with an extrusive origin). As are most carbonatites, the rock is composed of calcite (calcium carbonate - CaCO3), and it bubbles in acid. The tannish-brownish-grayish portions of the rock consist of rounded to subrounded particles - those are carbonatite lapilli from an ancient volcanic eruption. The white portions of the rock is calcite cement that binds the lapilli together. This rock can be called an extrusive calciocarbonatite or calciocarbonatitic lapillistone or welded calciocarbonatite.

This material formed at the ancient Kaiserstuhl Volcano, which is situated along a continental rift in Europe called the Upper Rhine Graben. The long-extinct volcano is now eroded away, but some of its extrusive rocks and much of the originally-underlying intrusive complex is still preserved.

Age: Langhian to Burdigalian, late Early Miocene to early Middle Miocene, 14-18 Ma

Locality: Kaiserstuhl Complex (a.k.a. Kaiserstuhl Volcanic Complex, Kaiserstuhl Carbonatite Complex), near Freiburg, southwestern Baden-Württemberg, far-southwestern Germany