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Messel pit
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The Messel Pit is a disused quarry near the village of Messel, about 35 km southeast of Frankfurt am Main, Germany. Bituminous shale was mined there. Because of its plethora of fossils, it has significant geological and scientific importance. The Messel Pit was declared a UNESCO World Heritage site on 9 December, 1995.
pit first became known for its wealth of fossils around 1900, but serious scientific excavation only started around the 1970's.
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Encyclopedia
The Messel Pit is a disused quarry near the village of Messel, about 35 km southeast of Frankfurt am Main, Germany. Bituminous shale was mined there. Because of its plethora of fossils, it has significant geological and scientific importance. The Messel Pit was declared a UNESCO World Heritage site on 9 December, 1995.
Depositional Characteristics
The pit first became known for its wealth of fossils around 1900, but serious scientific excavation only started around the 1970's. It is roughly 60 m below the local land and is about 1 kmē (1 km x 0.7 km to be exact). Fifty million years ago in the Eocene when the Messel deposits formed it was 10° further south than it is now, and its climate and ecology were very different. A large series of lakes, surrounded by lush sub-tropical forests supported an incredible diversity of life. The Messel lake bed was probably a center point for drainage from nearby rivers and creeks.
The pit deposits were formed during the Geiseltalian Period about 50 million years ago. Oil shale, formed by the slow anoxic deposition of mud and dead vegetation on the lake bed, is the primary rock at the site. Its sediments extend 130 m downward and lie atop an older sandstone foundation. But what gives the fossils within the shale such remarkable clarity and preservation were the unique depositional characteristics of the lake. The upper stratifications of the lake most certainly supported a variety of organisms, but the bottom was subject to little disturbance by current, spawning a very anoxic environment. This prevented many epifaunal and infaunal species from inhabiting this niche, and thus bioturbation was kept at a minimum. Overturn of the lake layers (caused by seasonal variations) lowered oxygen content near the surface and led to a periodic "die-off" of aquatic species. Combined with a relatively low rate of deposition (.1 mm/yr), this provided a prime environment for the preservation of fauna and flora.
Volcanic Gas Attacks
The area around the Messel Pit is believed to have been geologically and tectonically active during the Eocene, leading scientists hypothesize that events much like 1986 gas releases at Lake Nyos, Africa could account for the large deposition of non-aquatic species. Periodic subsurface shifts possibly released large concentrations of reactive gases (such as carbon dioxide and hydrogen sulfide) into the lake and adjoining ecosystems, killing susceptible organisms. During one of these releases, birds and bats might have fallen in if near the lake surface, and terrestrials could be overwhelmed when near the lake shore.
Fossils
The Messel Pit provides the most preserved evidence of Geiseltalian flora and fauna so far discovered. Most other sites are lucky to contain partial skeletons, but Messel boasts extensive preservation of structural integrity, even going so far as to preserve the fur, feathers, and "skin shadows" of some species, and the diversity of species is no less astonishing (thanks in part to the periodic gas attacks). A brief summary of some of the fossils found at the site follows:
- Over 10,000 fossilized fish of numerous species
- 1000s of aquatic and terrestrial insects, some with distinct coloration still preserved
- A plethora of small mammals including pygmy horses, large mice, primates, ground dwellers (opossums and armadillos), aardvark relatives, and bats.
- Large numbers of birds, particularly predatory species.
- Crocodiles, frogs, turtles, salamanders, and other reptiles or amphibians
- Over 31 distinct plant remains, such as palm leaves, fruits, pollen, wood, walnuts, and grapevines
Mammals
- Kopidodon, an extinct arboreal mammal
- Leptictidium, an extinct omnivorous hopping mammal (of the leptictid family)
- Propalaeotherium, an early relative of horses
- Ailuravus, a rodent
- Peradectes, a marsupial
- Palaeochiropteryx, a bat
- Lesmesodon, a small Creodont
- Eomanis, an early pangolin
- Eurotamandua, a scaleless, anteater-like pangolin
- Europolemur, a primate
- Paroodectes, a primitive carnivorous mammal
- Pholidocercus, an early hedgehog
- Messelobunodon, an early artiodactyl
- Godinotia, a prehistoric lemur-like monkey
Birds
- Palaeotis, a "proto-ostrich"
- Strigogyps sapea (formerly Aenigmavis)
- Messelornis, the Messel-bird; a relative of the sunbittern
- Masillastega, a freshwater booby
- The Messelasturidae, enigmatic carnivorous birds that looked like a mix between owls and hawks
- Palaeoglaux, a primitive owl with enigmatic breast feathers
- Palaeotis, a possible ostrich relative
- Paraprefica, an early potoo
- Masillaraptor, a primitive falcon
- Parargornis, related to the hummingbirds' ancestors
- Messelirrisor, tiny hoopoe-like birds
- Selmes (an anagram of "Messel"), a coliiform with stubby toes
- Gastornis (formerly Diatryma), a large, flightless predatory bird
Reptiles
- Asiatosuchus, a large crocodile
- Diplocynodon, an alligator
- Hassiacosuchus, a durophagous crocodile
- Palaeopython, a snake
- turtles
Fish
- bowfin
- perch
- gar
- eel
Insects
- Messel giant ant, a giant species of ant
- jewel beetle
- stag beetle
- rove beetle
Visitation
Exhibits from the pit may be seen in the Messel town museum and in the Museum of Hessen in Darmstadt (5 km from Messel) and also the Senckenberg Museum in Frankfurt (some 30 km from Messel). Casual visitors can park close to the pit and walk the ~300 m to a viewing platform from where the pit can be seen. Entrance to the pit is only possible as part of a specially organized tour.
See also
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