Age constraints on Atlantic evolution: timing of magmatic activity along the E Greenland continental margin

Abstract

S U M M A R Y:The results of a comprehensive K-At investigation of 130 petrographically selected rock and mineral specimens from the E Greenland Tertiary Igneous Province are reported. The new age data refine the chronology of this region. They suggest the following conclusions: (1) the lavas were extruded between 54 and 57 Ma; (2) the pre-flexure dyke swarm was intruded between 51 and 53 Ma; (3) the postflexure dyke swarm was intruded between 49 and 51 Ma; and (4) plutonic activity occurred at 50 Ma (Kangerdlugssuaq, Kraemers O, Lilloise, etc.), 42~45 Ma (Borgtinderne, Kap Deichman, etc.), 36 Ma (Kialineq), 38 and 28 Ma (Kong Oscars Fjord, Myggbukta).

40 Ar- 39 Ar ages of lavas from the southeast Greenland Margin, ODP Leg 152, and the Rockall Plateau, DSDP Leg 81

“…. Compilation of new radiometric ages presented in this paper and published ages from West Greenland (Larsen et al, 1992), East Greenland (Noble et al, 1988;Hansen et al, 1993;Upton et al, 1995), northwest Britain (Dagley and Mussett, 1986;Mussett, 1986), the Vøring Plateau (Boulter and Manum, 1989), and North Sea sediments (Knox and Morton, 1988;Morton et al, 1988). We cannot discount older ages in the eastern Atlantic SDRS because the lower lavas were not sampled.…”

“…First, there is a notable lack of reliable radiometric ages for many of the localities. Many of the K-Ar ages show a wide range as a result of alteration and excess 40 Ar (e.g., Noble et al, 1988). Comparison of the radiometric ages to age estimates derived from fossil assemblages can be problematic.…”

“…The Scoresby Sund area lavas have been radiometrically dated by 40 Ar-39 Ar incremental heating methods at 56.7 ± 4.3 Ma (2σ error) (Hansen et al, 1993). The most reliable K-Ar ages from the lavas near Kangerlussuaq indicate an eruption age of 56−54 Ma (Noble et al, 1988). To the north of Kangerlussuaq between 73° and 74°N, lavas from the lower part of the volcanic stratigraphy have 40 Ar-39 Ar ages of 58−57 Ma (Upton et al, 1995).…”

The North Atlantic Igneous Province: A review of models for its formation

“…This is a linear interpolation of the data points onto a regular grid with a 1˚ by 0.25˚ resolution. Dataset: Brooks and Gleadow (1977), Gleadow and Brooks (1979), Bugge et al (1980), Dickin (1981), Dickin and Jones (1983), Mussett (1986), Thompson et al (1987), Gibson et al (1987), Noble et al (1988), Hitchen and Ritchie (1993), Nevle et al (1994), Upton et al (1995), Pearson et al (1996), Hirschmann et al (1997), Price et al (1997), , , Storey et al (1998), Tegner et al (1998), Gamble et al (1999), Tegner and Duncan (1999), Moorbath et al (1968), Ross and Mussett (1976), Hardarson et al (1997), andFoulger (2006). Ren et al (2003), Jones and White (2003), Mackay et al (2005) and Knox (1998).…”

A reassessment of the role of ice sheet glaciation in the long-term evolution of the East Greenland fjord region

“…Rifting began again ∼18 Myr prior to breakup (Upton et al, 1995;Price et al, 1997) and culminated in a short (∼2 Myr) period of magmatism associated with crustal underplating (Schlindwein and Jokat, 1999) and the extrusion of subaerial basalts (Upton et al, 1995;Price et al, 1997). A later stage of magmatism at ∼30 Ma was associated with late Tertiary rifting and the separation at ∼25 Ma of a crustal fragment that is now incorporated in the Jan Mayen Platform (Noble et al, 1988;Price et al, 1997).…”