Marks are very important for figuring our parameters like current directions or speed, water depth or climate. For this purpose, marks need to be measured regarding size and geographic orientation directly in the outcrop.
The nearly parallel ripple tops indicate a single main wave direction, which is typical for coastal areas with a single constant wind directions.
Unlike current ripples, the luv and lea sides of wave ripples are almost identical. In current ripples, the side protected from the current is usually much steeper than the one facing the current, and the ridges do not repeatedly branch off as each of the rippels forms in a straight, continuous line.
Upper Bunter, Wutachschlucht (near Schattenmühle)
The ridges enclosing an angle of almost 90° are evidence for changing wave directions which is typical for areas near the shore with changing wind directions.
Unlike current ripples, the luv and lea sides of wave ripples are almost identical. In current ripples, the side protected from the current is usually much steeper than the one facing the current, and the ridges do not repeatedly branch off as each of the rippels forms in a straight, continuous line.
Upper Muschelkalk, Héming, Lorraine (F)
Fragment of a vertebra that was moved by a uni-directional current along the sea floor and left a tool mark.
Lower Keuper (Grenzbonebed), Crailsheim
Although they have some similarities to wave ripples, these ripples were formed in a river bed by the continuous forward-moving of sediment. Unlike wave ripples, both sides of the current ripples differ in steepness, with the steeper side facing towards the direction the current came from (on the picture from the upper right to the lower left). Also unlike wave ripples, the ridges do not branch. When further increasing its speed, the current may also form tongue-shaped current ripples, an effect that's already slightly visible on this piece.
The back of the slab shows negatives of the reptile trace Chirotherium (see also trace fossils).
Current ripples typically occur in fluvial systems with high transport energy. Their tongue shape is very characteristic and can also be observed in modern creeks and rivers.
Measurements of the shown specimen have revealed that the current originally came from the northeast. And really, it's a fact that the sediment for the Hauptsandstein of the Lettenkeuper was brought from the Baltic Shield to the Germanic Basin by large fluvial systems, spreading in NE-SW direction.
Lower Keuper (Lettenkeuper Hauptsandstein), Ilsfeld
Due to the salty pore water of playa plains and the arid climate in the Middle Keuper, halite crystals grew within the sediment until occasional rainfalls and floods lowered the salt concentration to a point that the previously grown crystals were dissolved again. The resulting hollow casts were then filled by sediment.
So, halite crystal marks are an evidence for the existence of salt lakes and basins in a desert-like environment with rare rain.
Middle Keuper (Estherienschichten), Speinshart