See more from this Division: Topical Sessions
See more from this Session: Exhumation of Continental Ultrahigh-Pressure Terranes
Abstract:
Zircons from the Tvaerdal Orthogneiss yield metamorphic rims that cluster in age from 409403 Ma and overgrow magmatic cores of 1676 and 1663 Ma in two samples, and range from ~17501000 Ma in a third sample. In contrast, zircons from three samples in the Jaettedal Paragneiss and two samples in the Kalkdal Paragneiss yield metamorphic rims that cluster in age from 438418 Ma with ArcheanEarly Neoproterozoic detrital cores. ArcheanEarly Neoproterozoic detrital zircons associated with 440420 Ma metamorphism in the Liverpool Land paragneisses suggests correlation with the Hagar Bjerg Thrust Sheet of Laurentian affinity, whereas Mesoproterozoic magmatic cores, which have not been identified elsewhere in Greenland, and ~400 Ma (U)HP deformation suggests correlation of the Tvaerdal Orthogneiss with the Western Gneiss Complex in Norway and of Baltican affinity (e.g., Augland et al., 2007). As such, the contact between the Tvaerdal Orthogneiss and the Jaettedal Paragneiss records an initial stage of (U)HP exhumation prior to displacement along the upper-crustal Hurry Inlet Detachment, and may represent a Caledonian lower-crustal suture between Baltica and Laurentia.
See more from this Division: Topical Sessions
See more from this Session: Exhumation of Continental Ultrahigh-Pressure Terranes