Posidonia Shale: Germany's Jurassic Marine Park
Walter Etter and Carol M. Tang
THE LOWER JURASSIC POSIDONIA SHALE (POSIDONIEN schiefer) of southern Germany and, especially, the Holzmaden region is one of the most celebrated of all Lagerstätten. This deposit has, in places, been quarried for centuries, and large numbers of splendidly preserved fossils have found their way into museums and private collections around the world. Since quarrying in the Holzmaden region continues, even today spectacular fossils are being uncovered. Famous finds include not only fully articulated marine reptiles and fish, but also articulated crinoids attached to logs and belemnites with preserved soft parts (Hauff and Hauff 1981; Seilacher 1990; Urlichs, Wild, and Ziegler 1994). The most frequently found fossils include, however, a variety of ammonites and bivalves, which can be found on almost every bedding plane. The black and laminated bituminous Posidonia Shale has long been treated as the prototype stagnation deposit (Seilacher 1982b; Seilacher, Reif, and Westphal 1985). This classification still holds true, although over the years it has become clear that there were several episodes with oxygenated bottom-waters (Röhl 1998; Röhl et al. 2001).
Quarrying in the Holzmaden region dates back for centuries. In fact, floor tiles coming from the Posidonia Shale can be found in the Hohenstaufen castle, built in the twelfth century (Seilacher 1990). Early attempts to distill oil from the highly bituminous black shales date back to the late sixteenth century (Seilacher 1990). Fossils have been found since that time (historical review in Urlichs, Wild, and Ziegler 1994). The first fundamental treatments of the Posidonia Shale and its fossils were published in the early nineteenth century by Schlotheim, Zieten, Quen