Crystalline rocks in the maar deposits of Messel: key to understand the geometries of the Messel Fault Zone and diatreme and the post-eruptional development of the basin fill

Seven remarkable new fossil species of parasitoid wasps (Hymenoptera, Ichneumonidae) from the Eocene Messel Pit

“…The Messel Pit Fossil Site lies on the eastern side of the Rhine rift valley within the Sprendlingen Horst, an uplifted Palaeozoic basement block framed by Cenozoic depressions. Volcanic activity during the transition from the Early to Middle Eocene around 49 to 47 Ma [ 35 ] led to the formation of several isolated volcanic and tectonic basins, one of them Messel [ 36 – 38 ]. Scientific drilling has proven that the former Lake Messel was a maar lake which formed due to phreatomagmatic activity [ 36 , 39 ].…”

Isotope compositions (C, O, Sr, Nd) of vertebrate fossils from the Middle Eocene oil shale of Messel, Germany: Implications for their taphonomy and palaeoenvironment

“…1A). The Sprendlinger Horst is formed by crystalline rocks of Carboniferous to lower Permian age that are partially covered by Upper Permian (Rotliegend) siliciclastic sediments composed of reworked plutonic basement rocks (Marell, 1989;Harms et al, 1999;Mezger et al, 2013). During the Eocene a major phase of volcanic activity with basaltic effusions occurred on the Sprendlinger Horst (49 to 47 Ma; Mertz and Renne, 2005).…”

“…During the Eocene a major phase of volcanic activity with basaltic effusions occurred on the Sprendlinger Horst (49 to 47 Ma; Mertz and Renne, 2005). The Eocene volcanism occurred presumably along tectonic faults (Mezger et al, 2013) and formed several isolated volcanic and tectonic basins, including Messel (Harms et al, 1999;Felder and Harms, 2004). The Grube Prinz von Hessen oil shale deposit, however, is not of volcanic origin and is, at the minimum, 2 Ma younger than Messel (Franzen, 2006).…”

“…Hence at the time Propalaeotherium dwelled the forested landscape around the Lake Messel the initial tuff ring deposits around the crater, formed 640 ka beforehand during the phreatomagmatic eruption, were probably already eroded away or -if still present -the crater wall was not the preferred habitat of Propalaeotherium. The Messel maar is surrounded by Upper Permian (Rotliegend) sediments, predominantly siliciclastic red beds, as well as Carboniferous igneous rocks such as granites, granodiorites, and diorites (Marell, 1989;Mezger et al, 2013). These Palaeozoic rocks represent the presumable bedrock substrate on which Propalaeotherium lived.…”

“…The maar formation has been 40 Ar/ 39 Ar dated to 47.8 ± 0.2 Ma using a basalt fragment from the pyroclastic lapilli tuff sequence below the oil shale (Mertz and Renne, 2005). The diatreme formed within felsic and mafic plutonic rocks (granite, granodiorite, diorite) of Carboniferous and Lower Permian age along the Messel Fault Zone that acted as pathway for the ascent of Palaeogene basaltic magma (Mezger et al, 2013). The lack of any Mesozoic clasts in the diatreme breccia indicates that the Eocene land surface around Messel was made up of Permian and/or Carboniferous rocks while Triassic sedimentary cover rocks were already eroded away (Felder and "Messel oil-shale" sand, gravel with oil shale fine gravel to clay, tuff, mostly graded amphibolite blocks, graded matrix with sand and clay gravel to clay, tuff, mostly graded lapilli tuff breccia (amphibolite, granite, granodiorite, "Rotliegend-sandstone"), graded Harms, 2004).…”