The closure of the Iapetus Ocean and Tornquist Sea: new palaeomagnetic constraints

Article Abstract:

The presence of volcanic rocks from the early Wenlock generate primary palaeomagnetic directions which show southern Britain's location in Mid Silurian period. Combined data show that the Iapetus Ocean was closed in its British and Scandinavian parts, the initial docking of eastern Avalonia was post-dated by the British Acadian deformation and convergence limits of southern Britain and Baltica are eliminated by the closure of the Tornquist Sea into theMid-Sularian period.

Paleozoic Era, Rocks, Igneous, Igneous rocks

---

Palaeomagnetic data from the Borrowdale Volcanic Group: volcano-tectonics and Late Ordovician palaeolatitudes

Article Abstract:

An analysis of palaeomagnetic data is presented. Sampling sites from the Borrowdale Volcanic Group generate high unblocking temperature magnetization components which postdate structural tilt. This postdated process also applies to block-faulted formation. Hydrothermal alteration during the late Ordovician period is linked with the magnetization process. The block-faulted synclinal structure bounding the Borrowdale area is considered part of the pre-Acadian stage.

Plate tectonics, Ordovician period

---

Geophysical investigation of the Honningsvag igneous complex, Scandinavian Caledonides

Article Abstract:

Magnetic and gravimetric studies of the Mageroy nappe of Norway reveal anomalies in the Honningsvag igneous complex (HIC). Modeling of the HIC regarding the anisotropy of remanence as well as gravimetric data reveals a tilting of from 60 to 80 degrees in the structure extending for greater than 50 km and with a depth of 6 km. Subsequent information indicate that the HIC was formed by brittle upper-crust motion without normally accompanying volcanic activity.

Reports, Scandinavia, Natural history, Geophysical research, Devonian period

Similar abstracts:

• Abstracts: The tectonostratigraphy and structure of the eastern Nepal Himalaya. Thrust tectonics of the Binalood Region, NE Iran
• Abstracts: The timing of high-temperature retrogression in the Reynolds Range, central Australia: constraints from garnet and epidote Pb-Pb dating
• Abstracts: Evidence for the multiple stage evolution of the subcontinental lithospheric mantle beneath the Eifel (Germany) from pyroxenite and composite pyroxenite/peridotite xenoliths
• Abstracts: The Iapetus suture zone in England, Scotland and eastern Ireland: a reconciliation of geological and deep seismic data
• Abstracts: Boron in granitic magmas: stability of tourmaline in equilibrium with biotite and cordierite. Tourmaline in a low grade clastic metasedimentary rock: an example of the petrogenetic potential of tourmaline

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.