User:Tobias1984/Draft Teisseyre-Tornquist zone

The Teisseyre-Tornquist Zone (or Tornquist-Teisseyre Zone) is a broad fault zone which extents from the Baltic Sea in the northwest, across Europe, to the Black Sea in the southeast, making it Europes longest tectonic linament. Although originally thought to be the suture between the East European Craton and West European Plattform, the true suture is today thought to lie farther to the southwest.

The northwestern continuation of the Teisseyre-Tornquist Zone is the Sorgenfrei-Tornquist Zone, which was regarded as the suture of two microcontinents Avalonia and Baltica. Today it is inerpreted as a intraplate structure to the north of the Avalonia-Balitica stuture. Nonetheless the ocean that seperated Avalonia and Baltica before the Caledonian Orogeny still carries the name Tornquist ocean.

The suture zone between the East European Craton and the different terranes of the Western European Plattform is referred to as the Trans European Suture Zone.

Discovery
The importance of the Teisseyre-Tornquist Zone for the geology of Europe was discovered by Wawrzyniec Teisseyre in 1883 and Alexander Tornquist in 1908. Although Teisseyre and Tornquist thought that they had discovered the suture between the East European Craton and the West European Plattform the real suture is now thought to run farther to the southwest (the [[Trans European Suture Zone).

Naming
In the beginning the Teisseyre-Tornquist Zone was known as either the Berdo-Narol-Scania Line, the Scania-Black Sea Line or the Baltic-Podole Line. The fault zone was first named Tornquist-Teisseyre Zone [sic] in 1969. Since then most scientific authors give Teisseyre seniority in the name of the fault zone.

Although both Teisseyre-Tornquist or Tornquist-Teisseyre are used in literature, the usage can be ambiguous. The Teisseyre-Tornquist Zone can refer either to the whole fault zone (including the Sorgenfrei-Tornquist Zone) or just the segment connecting the Baltic Sea with the Black Sea. The term Teisseyre-Tornquist Line can also refer to the whole fault zone or just the segment connecting the Baltic with the Black Sea. Some authors also favor the shorter Tornquist Zone for the whole fault zone.

The segment connecting the North Sea with the Baltic Sea is unambiguously referred to as the Sorgenfrei-Tornquist zone (STZ). It was named after Alexander Tornquist and Theodor Sorgenfrei.

Further ambiguity exists on where the two segments should be divided. Some authors favor the Rønne Graben (West of Bornholm) where the fault zone is seen to bend into a north-south orientation parallel to the Rønne Graben. Other authors favor a division in northwestern Poland where the Trans European Fault Zone connects with the Teisseyre-Tornquist Zone.

Geographic overview
From northwest to southeast the Sorgenfrei-Tornquist Zone and the Teisseyre-Tornquist Line cross the following geographical features:


 * Sorgenfrei-Tornquist zone:
 * North Sea
 * Denmark
 * Kattegat-Skagerrak
 * Sweden
 * Baltic Sea west of Bornholm


 * Teisseyre-Tornquist Line
 * Bornholm
 * Baltic Sea east of Bornholm
 * Poland
 * Ukraine
 * Romania
 * North Dobrogea Mountains
 * Black Sea

Teisseyre-Tornquist Zone
At the surface the TTZ does not correspond to a single linear feature but is a very broad zone of NW to SE trending faults. In the northwest the Teisseyre-Tornquist Zone branches into the Sorgenfrei-Tornquist Zone and the Trans European Fault Zone. In Poland the Tornquist-Teisseyre Zone runs parallel with the Trans European Fault Zone. Most of the fault zone is concealed by the Permian to Mesozoic sediments of the Polish trough. In southern Poland, western Ukraine and northwestern Romania the Tornquist-Teisseyre Zone is overthrust by the Carpathians. It resurfaces in central Romania in the Dobrogea Mountains.

Subsidence along the TTZ has produced many basins which are filled with up to 3500 m of sediments.

Sorgenfrei-Tornquist Zone
The TTZ lies at the southern boundary of Baltica, a area which is attributed to the Scevo-Norwegian orogen.

The Sorgenfrei-Tornquist Zone (STZ) developed during Late Carboniferous to Early Permian times. In map view it forms a westwards widening fault zone covering the Baltic Sea and Denmark. Within the STZ crustal blocks form a horst and graben structure.

The northern boundary of the Sorgenfrei-Tornquist zone is the Fennoscandian Border Zone. To the south of the STZ lie the Ringkøbing-Fyn High (RFH), the Caledonian Deformation Frontand the Trans European Suture Zone.

The southernmost fault of the STZ is the Trans European Fault(TEF), which acted as the northern boundary for the subsidence of the North German Basin.

The most important geological structure are (from north to south):
 * Börglum Fault
 * Mesozoic Branch of the STZ
 * Fjerritslev Fault
 * Norwegian and Danish Basin
 * Vinding Fracture Zone
 * Ringkøbing-Fyn High


 * Caledonian Deformation Front
 * Rømø Fault
 * Trans European Fault

Geological history
Four major plate tectonic events have reactivated the TTZ :
 * 1) Caledonian orogeny
 * 2) Variscan orogeny
 * 3) Rifting during the Permian and the Mesozoic
 * 4) Basin inversion during the Late Cretacous to Early Cenozoic

Pre-Caledonian Orogeny
Before the Caledonian orogeny, the Tornquist ocean seperated Gondwana and Baltica. Rifting of the Tornquist ocean was contemporaneous with the breakup of Rodinia which took place in the Proterozoic. Subsequent ocean spreading coincided with the northward movment of Baltica, lasting till the Ordovician. Subduction was initiated at the continental margin of Avalonia during the Ordovician at which time the basin started to become narrower. The closure of the Tornquist ocean continued till Avalonia and Baltica collided at the Ordovician-Silurian boundary as part of the Caledonian orogeny.

Caledonian Orogeny
Three continents collided during the Caledonian Orogeny: Avalonia, Baltica and Laurentia. Avalonia and Baltica collided at the Ordovician-Silurian boundary.

Post-Caledonian orogeny
Introduction???????


 * The earliest known movements along the Tornquist-Teissyre Line were sinistral strike-slip movements during the Caledonian orogeney.
 * During the Late Caboniferous to Early Permian the TTL was reactivated as a dextral strike slip fault.
 * Starting in the Perimian and lasting into Late Jurassic times, extension along the TTL generated the Polish and Danish Troughs . It was also reactivated when the Proto-Pannonian basin developed and the Moesia microcontinent moved southeastwards.
 * In Mid Creataceous times the TTL was reactivated during the opening of the Black Sea.
 * Late Cretaceous to Early Paleocene compression led to basin inversion of the Polish Trough.
 * In the Ukraine and the northeaster part of Romania the Teisseyre-Tornquist zone was covered by the Carpathians.

Recent activity along the Teisseyre-Tornquist Zone
The Teisseyre-Tornquist line has remained active and is the source of frequent earthquakes:
 * A historic earthquake happened in Thy (Jutland, Denmark).
 * On 15. June 1985 a earthquake occurred in the ocean north of Zealand (Denmark).
 * The last larger earthquake occured on 16. December 2008 which reached a magnitude of 4.7 on the Richter scale. The epicenter was located 40 km east of the city of Malmö (Sweden).

Methods of investigation
Seismic investigations show that there is a notable difference in shear wave velocity to the southwest (slow waves) and northeast (fast waves) of the TTZ.

Geophysical methods play a very important role in the investigation of the Teisseyre-Tornquist Zone. Most of the fault zone is covered by a thick sedimentary cover. The late Paleozoic to recent Sediments were deposited when rifting along the Teisseyre-Tornquist Zone caused subsidence (e.g. Southern-Permian-Basin, Polish Trough, Danish Basin). Some parts of the TTZ are covered by sediments of younger rift systems. In general the crust northeast of the TESZ is thicker (45 versus 30 km) and older (metamorphic ages from 3000 to 800 million years) than the crust to the southwest.

Suggested readings

 * Ziegler, Peter Alfred (1990). Geological Atlas of Western and Central Europe 2nd Edition. Shell Nederland. ISBN 9066441259.
 * Blundell, Derek, Roy Freeman & Stephan Mueller (1992). A continent revealed - The European Geotraverse. ISBN 052142948X.

Draft Stuff
http://www.sgu.se/sgu/sv/produkter-tjanster/nyheter/nyheter-2008/Jordskalv-i-Skane.html ref name="McKerrow et al 2000">. http://2dgf.dk/xpdf/bull46-2-145-160.pdf

Teisseyre-Tornquist Zone