Kalkowsky's stromatolites and oolites (Lower Buntsandstein, Northern Germany)

In his pioneer work Kalkowsky (Zeitschrift der deutschen geologischen Gesellschaft 60:68-125, 1908) coined the terms "ooid" and "stromatolite" for carbonate structures occurring in the Lower Triassic Buntsandstein of northern Germany. Stromatolites occur almost exclusively at the surface of thick oolite beds. They consist of thin laminated crusts, small columns or 2m high compound domes. Two types of microstructures can be distinguished, spongy-fenestrate and fan-like fabrics. Photoautotrophic growth forms suggest a microbial, most likely cyanobacterial origin. Kalkowsky (Zeitschrift der deutschen geologischen Gesellschaft 60:68-125, 1908) saw a continuum from concentric ooids to laminated stromatolites. Both should be produced by lime-secreting phyto-organisms. He also proposed shallow salt lake shores as a preferred stromatolitic environment.