Nær Jan Mayen hryggurinn inn undir Austfirði? - verkefni lokið
Fréttatilkynning verkefnisstjóra
Geological formations have been mapped in a region east of Borgarfjördur eystri and south to Lodmundarfjördur, named Víknaslóðir.
Geological formations have been mapped in a region east of Borgarfjördur eystri and south to Lodmundarfjördur, named Víknaslóðir. The abundance of silicic rocks is surprisingly high or approximately half of all the mapped strata. The bedrock is composed of basaltic lavas with a slight WSW dip. A detailed map of Breiduvik has been published and a more detailed map of the whole region is expected by the end of the year 2015.
Heiti verkefnis: Nær Jan Mayen hryggurinn inn undir Austfirði?
Verkefnisstjóri: Olgeir Sigmarsson, Raunvísindastofnun
Tegund styrks: Verkefnisstyrkur
Styrkár: 2013-2014
Fjárhæð styrks: 13,207 millj. kr. alls
Tilvísunarnúmer Rannís: 130308-051
Unusually abundant silicic magmatism lasted for approximately 4 Ma at the Neogene Breiduvik Volcano, East-Iceland. In total 247 detrital zircons were dated with the U/Pb method and O- and Hf isotope ratios measured. The age span between minimum (11.2 ±0.7 Ma) and maximum (15.0 ±0.9 Ma) measured zircon ages is 3.8 ±1.6 Ma. The εHf ranges from 12.2 to 16.3 and lies within the range observed for Recent basalts from Iceland, excluding a continental crustal melting at the origin of the silicic magmatism. The low δ18O in zircons ranges from 0.7-3.7‰ suggest dominant crustal contribution during the silicic magma generation. The modern analogue of Breiduvik volcano is the active Torfajökull volcanic complex. Both these volcanoes share similar tectonic settings, namely an intersection of a propagating rift with a transform fault system. This setting is thus favorable for a long-lived silicic magmatism most likely due to easy access to fertile hydrothermally altered basaltic crust.
