Flame marl
The flame marl is a lithological unit of the Lower Cretaceous ( Alb ) in Germany.
In the Lower Saxony area it reaches a thickness of 110 to 150 m in the area of the sack trough . The flame marl is named for its "flamed" appearance. According to J ORDAN (1968), this appearance can be traced back to digging traces of burrowing organisms, which essentially consist of flooded pebbly sponge needles . The silica enriched in this way forms black streaks when weathered, which then give it its characteristic appearance. Furthermore, Jordan divides the flame marl into five different lithological units. The flame marl is a slightly clayey to slightly sandy marlstone . It is colored yellow to ocher, while the streak-like flames are dark gray to black. The rock is pebbly bound and has a high hardness.