Other
Scientific paper
Feb 1979
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1979e%26psl..42..288s&link_type=abstract
Earth and Planetary Science Letters, Volume 42, Issue 2, p. 288-310.
Other
2
Scientific paper
Lower Palaeozoic volcanism in southeast Ireland was apparently associated with the development and infilling of a major NE-SW submarine trough. The volcanic rocks range from Cambrian to Silurian in age, the most productive and widespread activity being in the Upper Ordovician. These rocks were deformed in the Caledonide orogeny and are now preserved in two geographically distinct belts, some 50-60 km apart. The eruptions mainly took place below the sea, building up sea mounts and volcanic islands. In the Northern Belt basalts and andesites predominate, whilst the Southeastern Belt is dominated over much of its extent by rhyolite eruptives, though basalts, andesites and dacites are still widely represented. These rocks have all been subjected to some degree of degradational metamorphism, but in many cases this has fallen far short of total recrystallisation. The alteration seems to have been essentially the result of syn- or immediately post-emplacement submarine weathering and, locally, hydrothermal metasomatism. The effects of burial metamorphism superimposed on this have in some cases resulted in greenschist facies assemblages, but these are far from ubiquitous and the common grade of metamorphism is somewhat lower. The results of Caledonide regional metamorphism are slight and though a pervasive cleavage is commonly imposed on the volcaniclastic rocks and intercalated sediments, recrystallisation is at a very low grade. An assessment of the effects of this alteration has led to the conclusion that chemical data from selected volcanics may be used to test the genetic kinship of the eruptives in the two belts, and further, that ascription to specific tectonic settings may be attempted using both major and minor element discriminants. The results of this study suggest that the Upper Ordovician volcanic rocks of east and southeast Ireland belong to the orogenic volcanic series, are essentially calc-alkaline, and were erupted on the margins of a continental plate which thickened in general towards the southeast above a subduction zone which dipped to the southeast. Further, the observed volcanics represent a late stage in the evolution of the system, when compositions approaching the shoshonitic were being erupted.
Stillman C. J.
Williams Thomas C.
No associations
LandOfFree
Geochemistry and tectonic setting of some Upper Ordovician volcanic rocks in east and southeast Ireland does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Geochemistry and tectonic setting of some Upper Ordovician volcanic rocks in east and southeast Ireland, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Geochemistry and tectonic setting of some Upper Ordovician volcanic rocks in east and southeast Ireland will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-829543