Search for dissertations about: "collisional orogeny"

Showing result 6 - 8 of 8 swedish dissertations containing the words collisional orogeny.

  2. 6. New Zircon geochronological and Nd isotopic evidence for Neoproterozoic crust reworking events in the Abas terrane, Yemen

    Author : Fitsum Girum Yeshanew; Victoria Pease; Martin Whitehouse; Hugh Rollinson; Kjell Billström; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Precambrian; Arabian Shield; magmatism; U-Pb; zircon; post-collisional magmatism; Nd isotopes; Geology; geologi;

    Abstract : The Arabian-Nubian Shield is an excellent natural laboratory to study crust formation processes during the Neoproterozoic. It is one of the largest juvenile tracts of continental crust formed during this time. It diachronously evolved between the breakup of Rodinia (c.780 Ma) and amalgamation of Gondwana (c. READ MORE

  4. 7. Inversion of Magnetotelluric Data Constrained by Borehole Logs and Reflection Seismic Sections

    Author : Ping Yan; Thomas Kalscheuer; Laust Pedersen; Maria Garcia Juanatey; Andreas Junge; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Magnetotellurics; constrained inversion; borehole logs; seismic; COSC; Alnö alkaline and carbonatite; airborne VLF; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

    Abstract : This thesis presents two new algorithms for doing constrained Magnetotelluric (MT) inversion based on an existing Occam 2D inversion program. The first algorithm includes borehole resistivity logs as prior information to constrain resistivity directly in the vicinity of boreholes. READ MORE

  5. 8. Mesoproterozoic crustal evolution in Southern Africa

    Author : Åsa Pettersson; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Namaqua-Natal province; Mezoproterozoic; geochronology; U-Pb zirkon dating; Sm-Nd model ages; Ar-Ar dating; Southern Africa;

    Abstract : The objects of this thesis were to use geochronology to investigate crustal evolution of part of Southern Africa that formed during a global event, resulting in the ~1 Ga supercontinent Rodinia. The timing of assembly by continent-continent collisions and the position of the individual continental blocks of this ancient landmass is still largely unknown. READ MORE