Trilobiten.de

[Jens]

Hier habe ich noch einen Abstrakt, der den Begriff Terran am Beispiel von Baltica erklärt. So dürfte dann auch der Terminus Baltoskandia, der öfters in den Literatur-Überschriften auftaucht, verständlicher werden.


L. Robin M. Cocks, and Trond H. Torsvik (2005): Baltica from the late Precambrian to mid-Palaeozoic times: The gain and loss of a terrane's identity. - Earth-Science Reviews, 72, (1-2): 39-66.

Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
Geodynamics Centre NGU, Leiv Eirikssons vei 39, N-7491 Trondheim, Norway


Abstract
The old terrane of Baltica occupies the mass of northern Europe eastwards to the Urals and lies mostly to the north of the Trans-European Suture Zone. The core, the East European Craton, is thick and formed of rocks dating back to well over 3 billion yr, and Protobaltica can be identified as forming part of the supercontinent of Rodinia at about 1 billion yr ago. Following Rodinia's break up at about 800 Ma, Protobaltica remained attached to Laurentia until it became the newly independent Baltica at between 570 and 550 Ma, with the inauguration of plate spreading to form the northern part of the Iapetus Ocean. To the south, during the Early Cambrian, Baltica was separated from Gondwana by the relatively narrow Ran Ocean. Baltica remained a separate terrane until its docking, firstly with Avalonia at the very end of the Ordovician (443 Ma), and then with Laurentia during the Silurian in the Scandian part of the Caledonide Orogeny. The terrane was much enlarged in the Vendian to include the areas such as Timan–Pechora now lying to the north as they became accreted to Baltica during the late Precambrian Timanide Orogeny. During the Cambrian and Ordovician, Baltica firstly rotated through more than 120° and then drifted northwards from high to low palaeolatitudes. New maps present Baltica's outline and progressive positioning, its late Precambrian and Lower Palaeozoic history, and the Cambrian, Ordovician and Silurian land, basins and biofacies belts within and around it. Some of the Lower Palaeozoic faunas are reviewed briefly: the oceans surrounding Baltica were so wide during the Early Ordovician that a substantial part of the benthic fauna of trilobites, brachiopods and other phyla were endemic. As those oceans narrowed, so the faunas of Baltica became progressively more similar to those of adjacent terranes. Some plankton distributions augment the palaeomagnetic data in latitudinal positioning.

Keywords: Baltica; Cambrian; Ordovician; Silurian; paleogeography; Avalonia; Iapetus Ocean

Na, alles klar.
Sedimente (z.B. kambrische Alaunschiefer wie auf Bornholm) von Baltica sind in der G14 nur wenig nördlich von Rügen erbohrt worden. Der Krustensplitter Avelonia, der den Nrden Deutschlands, Polens umfasst und auch weiter westlich bis England verfolgbar ist, schob sich also am Ende des Ordoviziums bis zum Silur auf den Südteil von Scandinavien. Es ist nach geophysikalischen Messungen ziemlich wahrscheinlich , daß sich ehemalige Südrand Baltica noch deutlich weiter nach Süden erstreckt hat und nun in vielen Kilometern Tiefe unter Avelonia bei uns in Meck-Pomm verborgen liegt.

Grüsse,

Jens