Mainz Basin

Mainz Basin is the name for a tertiary sea basin, which occupied the site of today's Rheinhessen about 38-12 million years ago ( mya ). The Mainz Basin is a bay of an arm of the sea, the ( a marginal sea of the Paleogene in the open North Atlantic ) with the Paratethys ( a marginal sea of the closing Tethys itself ) joined in the Paleogene briefly the former North Sea.

• 3.1 The Oligozänmeer
• 3.2 The Miozänmeer

Emergence of the Mainz Basin

Rhine Graben

In the Carboniferous, about 300 mya, came together united the North American and European plate ( Laurussia ) with the South Platte, which included the future South America, Africa, India, Australia and Antarctica ( Gondwana ) together. Here, a zone of weakness in the earth's crust, the so-called Mediterranean Mjösen zone, which stretches from the area of present-day Oslo fjord to the Rhone delta was formed. In the early Tertiary, about 50 mya, began in its northeastern part of the collapse of the Upper Rhine Graben ( between Mainz and Basel).

A wedge-shaped portion of the earth's crust sank into a grave structure from several kilometers deep. In the lateral ascending mountain floes to streams and rivers have incised and the erosion contributed by Black Forest and the Vosges rock to a thickness of about 2,000 m from. The rubble filled the Upper Rhine Graben. In places, the thickness of these sediments is 4000 m. The lowering of the grave breach holds about 1 mm per year until today and also aim to uplift the Edge Mountains (0.5 mm / yr ). The Broken Earth's crust has opened the magma at some points the way to the earth's surface and led to the formation of hot springs and volcanoes, such as in the area of the Imperial chair, about 18 mya. The ongoing crustal movements in the Upper Rhine Graben express themselves even today in smaller earthquakes.

Rocks

The vortertiäre subsoil of the Mainz Basin consists predominantly of rocks of the Paleozoic. In the peripheral areas (ie in former coastal zones ) rhyolite are vulkanotektonischen origin from the Permian ( Bad Kreuznach, Neu-Bamberg, Rheinhessen Switzerland) and Taunus quartzite and shale from the Devonian (Hunsrück, Taunus, Rochusberg ). Mesozoic sediments have not been found in the ground, that is modern ( tertiary ) layers lie here directly to those of the Paleozoic.

The Tertiary sea of the Mainz Basin

The collapse of the Rhine graben, which in the Eocene ( 50-38 mya ) began and continued during the Oligocene to the north, was accompanied by lateral extensions. The most important of them was the " Mainz Basin ", a flat, up to 50 m deep bay.

There were two long-lasting marine deposits, the Oligozänmeer ( 38-25 mya ) and the Miozänmeer ( 25-12 mya ) with an intermediate phase of silting.

The Oligozänmeer

The Oligozänmeer flooded the area now Rheinhessische hill country and surged against the hard quartzites of the Rhenish Massif and the foothills of Kreuznacher Ryolithmassivs. An inlet connected the Mainz Basin and the North Sea and the tropical warm southern sea. The mean annual temperature at the time was 18 ° C, compared to 10.5 ° C today. The sea and the shore zones were quite comparable with the present-day Caribbean: Subtropical temperatures, sandy beaches with palm trees and laurel trees and water crocodiles, sea turtles, manatees and amongst many other fish species numerous rays and sharks. At the country lived flamingos, pelicans, rhinos, tapirs, monkeys and elephants.

The Oligozänmeer superimposed on the pelvic floor following layers from: First Rupelton, slow sand and Cyrenemergel (gray- green marl from brackish water werdendem ) and finally freshwater layers. In the coastal areas of the Lower and Upper sea sand were deposited.

The Miozänmeer

After temporary land formation in Oberoligozän contacted the Miocene (25 mya ) again a reduction and thus a second marine formation a. In contrast to the sandy- marly deposits of calcareous deposits Oligozänmeeres now came to the paragraph that give today's plateaus and hills with their typical Kalkflora the stamp.

The Miozänmeer superimposed layers from the following: First, the Cerithienschichten (after the horn snail Cerithium ), then Corbiculaschichten (consisting of the Asian clam Corbicula fossils ) and finally Hydrobienkalk ( corkscrew -wound mud snail Hydrobia elongata, 3-4 mm)

The calcareous shells of Hydrobia occur not only in the limestone quarries of Weisenau, Bude home and Amoeneburg before billions of times, and many homes in Rheinhessen consist almost entirely of this limestone.

Country Education

On the Hydro Bien layer followed during the lower Miocene, after a Verbrackung and increasing Aussüßung of seawater ( as before when Oligozänmeer ), the emergence of the mainland, as it looks today. The former coastal strip with its typical fossils can still clearly visible on well-preserved outcrops in the southwest corner of Rheinhessen. Overall, the area was flooded many millions of years, with about 250 m thick sediments were deposited.

In the subsequent Pliocene ( 12-3 mya ) was formed in the formed by the sediments, gently undulating landscape is a flow system consisting of Ur -Rhine, Main and great- great- Nahe. The Ur -Rhine meandered from Upper Alsace coming over Worms, Eppelsheim, Wißberg, Ockenheim to Bingen.

Cover the sediments of the ancient Rhine in places the remains of animals and plants, so that today the flora and fauna can be from 10 mya very well reconstructed in Rheinhessen. These layers are called Dinotheriensande. The naming was done after the tusker Dinotherium giganteum ( " Huge animal terror ", also called " elephant tusks ", because of its two downward bent lower incisors ), which reached up to 5 m shoulder height. The first fossil of this species was found in the first half of the 19th century in Eppelsheim. The original is now in the British Museum of Natural History in London. Original casts are as numerous other fossils of the Tertiary Rhine-Hesse, the Natural History Museum in Mainz and the Wiesbaden Museum to see.

A 1983 compiled list of the mammal species called almost 50 names (for example, bear, hyena, tapir, ancient horse Hipparion, rhino, saber-toothed cat, antelope, giant sloth ). Especially famous is the 1820 at Eppelsheim discovered 28 cm long thigh bone of the ape Dryopithecus fontani. He is known worldwide as the historically first discovery of an extinct apes.