Geology and limnology of the Enspel Formation (Chattian, Oligocene; Westerwald, Germany)

Abstract

Lake Enspel was a deep lake which developed in a small trachytic caldera or Bims volcano. In normal times, the lake was meromictic and eutrophic and had no outlet. Background sedimentation together with periodical phytoplankton blooms led to laminated, undisturbed sediments that alternated with coarse mass flows and/or turbidites. During turnovers caused by these episodical sediment inputs, the lake became oligotroph. Mesophytic forest extended right down to the lake edge. Approximately, 230,000 years after the onset of lake sedimentation, a basaltic lava flow, caused by a nearby eruption, filled the lake up in a single event.