Search for dissertations about: "crustal reworking"

Showing result 1 - 5 of 7 swedish dissertations containing the words crustal reworking.

  2. 1. Evolution of continental crust in the Proterozoic : growth and reworking in orogenic systems

    Author : Andreas Petersson; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; crustal reworking; Proterozoic; O-isotopes; Lu–Hf; U–Pb; zircon; Crustal growth;

    Abstract : To understand the growth of continental crust, the balance between juvenile mantle derived extraction, infracrustal reworking and crustal recycling, needs to be estimated. Since the beginning of the century, the use of coupled in situ zircon U–Pb, Lu–Hf and O isotope analyses as a tool to address these questions have increased exponentially. READ MORE

  4. 2. Crustal evolution of the Arabian–Nubian Shield : Insights from zircon geochronology and Nd–Hf–O isotopes

    Author : Fitsum Girum Yeshanew; Victoria Pease; Martin J. Whitehouse; Robert J. Stern; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Gondwana; Arabian–Nubian Shield; Azania; zircon U–Pb–O–Hf isotopes; Nd isotopes; Cambrian Sandstones; juvenile; pre–Neoproterozoic; reworking; Geology; geologi;

    Abstract : The Arabian–Nubian Shield (ANS) represents a major site of juvenile Neoproterozoic crustal addition on Earth and documents Neoproterozoic tectonics bracketed by two supercontinent cycles, namely the fragmentation of Rodinia and the amalgamation of Gondwana. There is general consensus that the ANS formed by juvenile magmatic arc accretion and subsequent shield–wide post–tectonic magmatism. READ MORE

  5. 3. 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

  6. 4. Proterozoic crustal evolution in southcentral Fennoscandia

    Author : Karin Appelquist; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Transscandinavian Igneous Belt; TIB; Eastern Segment; Habo Volcanic Suite; Malmbäck Formation; U-Pb zircon ion probe dating; Nd isotopes; geochemistry; Hallandian; Danopolonian;

    Abstract : The Transscandinavian Igneous Belt (TIB) and the Eastern Segment of the Southwest Scandinavian Domain reflect advanced stages of continental growth within the Fennoscandian Shield. The relationship between the two units is not clear, mainly because N-S trending shear zones of the Protogine Zone transect the border zone. READ MORE

  7. 5. 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