Mantle underplating, granite tectonics, and metamorphic P-T-t paths: comment and reply
Article Abstract:
The 'granite tectonics' model which proposes the plate-scale convective overturn of unstable crust above mafic magma is invalid because it contradicts geological evidence including Archean granite-greenstone terrains. In addition, magmas do not remain at or near their generation sites. Rather, they quickly migrate from generation sites into fractures. It is argued, however, that the model, which contains evidence for high heat flow and crustal overturn processes, is feasible since it contributes to the understanding of crustal evolution in ensialic intraplate settings.
Publication Name: Geology
Subject: Earth sciences
ISSN: 0091-7613
Year: 1997
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Protorezoic low-Ti iron-oxide deposits in New York and New Jersey: relation to Fe-oxide (Cu-U-Au-rare earth element) deposits and tectonic implications: comment and reply
Article Abstract:
The plutonic and posttectonic origins of the Lyon Mountain Gneiss (LMG) is contradicted by the predominance of metamorphic textures. Furthermore, the pretectonic origin of LMG does not classify the host rock to Fe oxide (Cu-U-Au-rare earth element) type. These observations are challenged by a recent isotopic study that relates the emplacement of LMG with Ottawan deformation in the Adirondack Highlands. The relevance of LMG to low-Ti Fe-oxide ores as well as its tectonic origins are also explained.
Publication Name: Geology
Subject: Earth sciences
ISSN: 0091-7613
Year: 1996
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