Present and past influence of the Iceland Plume on sedimentation

Abstract

The Cenozoic development of the North Atlantic province has been dramatically influenced by the behaviour of the Iceland Plume, whose striking dominance is manifest by long-wavelength free-air gravity anomalies and by oceanic bathymetric anomalies. Here, we use these anomalies to estimate the amplitude and wavelength of present-day dynamic uplift associated with this plume. Maximum dynamic support in the North Atlantic is 1.5–2 km at Iceland itself. Most of Greenland is currently experiencing dynamic support of 0.5–1 km, whereas the NW European shelf is generally supported by <0.5 km. The proto-Iceland Plume had an equally dramatic effect on the Early Cenozoic palaeogeography of the North Atlantic margins, as we illustrate with a study of plume-related uplift, denudation and sedimentation on the continental shelf encompassing Britain and Ireland. We infer that during Paleocene time a hot subvertical sheet of asthenosphere welled up beneath an axis running from the Faroes through the Irish Sea towards Lundy, generating a welt of magmatic underplating of the crust which is known to exist beneath this axis. Transient and permanent uplift associated with this magmatic injection caused regional denudation, and consequently large amounts of clastic sediment have been shed into surrounding basins during Cenozoic time. Mass balance calculations indicate agreement between the volume of denuded material and the volume of Cenozoic sediments deposited offshore in the northern North Sea Basin and the Rockall Trough. The volume of material denuded from Britain and Ireland is probably insufficient to account for the sediment in the Faroe-Shetland Basin and an excess of sediment has been supplied to the Porcupine Basin. We emphasize the value of combining observations from both oceanic and continental realms to elucidate the evolution of the Iceland Plume through space and time.

Cenozoic post-rift sedimentation off northwest Britain: Recording the detritus of episodic uplift on a passive continental margin

“…We previously analyzed the exhumation history of the British Isles using Apatite Fission Track Analysis (AFTA) and other quantitative techniques, concluding that there were several episodes of Cenozoic exhumation (Paleocene, EoceneOligocene and Miocene; Hillis et al, 2008;Holford et al, 2009). We argued that the distribution and chronology of Cenozoic exhumation are not consistent with a dominant control by Paleocene uplift induced by the Iceland plume, as has been proposed (White and Lovell, 1997;Jones et al, 2002), and that episodic intraplate compression, driven by plate boundary forces was the principal cause of uplift responsible for the observed multiple phases of exhumation (Holford et al, 2009). …”

“…The Cenozoic sedimentary rocks in the basins surrounding the British Isles, with particular focus on the Paleocene, have been interpreted as the erosional products of source areas uplifted due to the Iceland plume, and sedimentary patterns have been taken as a potentially sensitive measure of plume activity (White and Lovell, 1997;Jones et al, 2002).…”

Understanding the offshore flood basalt sequence using onshore volcanic facies analogues: an example from the Faroe–Shetland basin

“…Significantly, this accommodation space was present and being filled by both the lava sequence 2 and lava sequence 1, and provides important additional constraints on models used to look at the spatial and aerial extent of uplift prior to the onset of volcanism (e.g. Jones et al 2002;Maclennan & Jones, 2006). Figure 7 shows a thickness map for the interpreted hyaloclastite volcanic rocks that are considered to be present in both the lava sequence 2 and the lava sequence 1.…”

Cenozoic vertical motions in the Moray Firth Basin associated with initiation of the Iceland Plume

“…1995; White and Lovell, 1997;Jones et al, 2002]. Pulses of increased sedimentation into the North Sea occurred during the Paleocene (Figure 14), particularly 59-54 Ma [Reynolds, 1994;Liu and Galloway, 1997;Clarke, 2001], probably as a result of plume-related uplift [White and Lovell, 1997].…”

“…However, there is no evidence of compression, such as folding, in Miocene age North Sea sediments. The Miocene uplift event could be due to the relative movement of Europe toward the Iceland Plume [Rohrman and van der Beek, 1996;Jones et al, 2002] resulting in renewed transient dynamic uplift above the Iceland Plume which has continued to the present day. The Miocene event could not be better distinguished in this study due to lack of late Cenozoic data points; few Cenozoic horizons have been dated in the commercial well logs.…”