New Developments in the Appalachian-Caledonian-Variscan Orogen
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New analytical and field techniques, as well as increased international communication and collaboration, have resulted in significant new geological discoveries within the Appalachian-Caledonian-Variscan orogen. Cross-Atlantic correlations are more tightly constrained and the database that helps us understand the origins of Gondwanan terranes continues to grow. Special Paper 554 provides a comprehensive overview of our current understanding of the evolution of this orogen. It takes the reader along a clockwise path around the North Atlantic Ocean from the U.S. and Canadian Appalachians, to the Caledonides of Spitsbergen, Scandinavia, Scotland and Ireland, and thence south to the Variscides of Morocco.
Provenance control on the distribution of endogenic Sn-W, Au, and U mineralization within the Gondwana-Laurussia plate boundary zone
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Published:May 19, 2022
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CiteCitation
Rolf L. Romer, Uwe Kroner, 2022. "Provenance control on the distribution of endogenic Sn-W, Au, and U mineralization within the Gondwana-Laurussia plate boundary zone", New Developments in the Appalachian-Caledonian-Variscan Orogen, Yvette D. Kuiper, J. Brendan Murphy, R. Damian Nance, Robin A. Strachan, Margaret D. Thompson
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ABSTRACT
The Paleozoic plate boundary zone between Laurussia and Gondwana in western Pangea hosts major magmatic and hydrothermal Sn-W-Ta, Au, and U mineralization. Individual mineral deposits represent the results of the superposition of a series of exogenic and endogenic processes. Exogenic processes controlled (1) the enrichment of the ore elements in sedimentary protoliths via residual enrichment during intense chemical weathering and via climatically or tectonically controlled redox traps, (2) the spatial distribution of fertile protoliths, and, thus, eventually (3) the spatial distribution of mineralization. Endogenic processes resulting in metamorphism and crustal melting controlled the mobilization of Sn-W, Au, and U from these enriched protoliths and, thus, account for the age distribution of Sn-W and Au mineralization and U-fertile granites. It is the sequence of exogenic and endogenic processes that eventually results in the formation of mineralization in particular tectonic zones. Whereas the endogenic processes were controlled by orogenic processes during the assembly of western Pangea itself, the exogenic processes were linked to the formation of suitable source rocks for later mineralization. The contrasting distribution of magmatic and hydrothermal Sn-W-Ta, Au, and U mineralization on the Laurussia and Gondwana sides of the plate boundary zone reflects the contrasting distribution of fertile protoliths and the contrasting tectonic situation on these margins. The Laurussian margin was an active margin during most of the Paleozoic, and the distribution of different mineralization types reflects the distribution of terranes of contrasting provenance. The Gondwanan margin was a passive margin during most of the Paleozoic, and the similar distribution of a wide range of different metals (Sn, W, Ta, Au, and U) reflects the fact that the protoliths for the various metals were diachronously accumulated on the same shelf, before the metals were mobilized during Acadian, Variscan, and Alleghanian orogenic processes.
- Acadian Phase
- actinides
- active margins
- Alleghany Orogeny
- alteration
- Appalachians
- Archean
- Armorica
- Avalonia
- black shale
- Bohemian Massif
- Central Europe
- Central Massif
- chemical weathering
- clastic rocks
- continental margin
- crust
- Eh
- endogene processes
- Europe
- faults
- France
- global
- gold ores
- Gondwana
- granites
- hydrothermal alteration
- Iapetus
- Iberian Peninsula
- igneous rocks
- Laurussia
- lower Paleozoic
- magmatism
- mantle
- marine environment
- metal ores
- metals
- metamorphism
- metasomatism
- mineral deposits, genesis
- mineralization
- New England
- North America
- organic compounds
- orogeny
- Paleozoic
- Pangaea
- partial melting
- passive margins
- pegmatite
- placers
- plate boundaries
- plate tectonics
- plutonic rocks
- Precambrian
- Proterozoic
- protoliths
- Rheic Ocean
- sea-level changes
- sedimentary rocks
- shear zones
- shelf environment
- Silurian
- Southern Europe
- spatial distribution
- structural controls
- subduction
- terranes
- tin ores
- Tornquist-Teisseyre Zone
- tungsten ores
- United States
- upper Precambrian
- uranium ores
- Variscan Orogeny
- weathering
- Western Europe
- magmatic arcs