Early Tertiary basalts from the Labrador Sea floor and Davis Strait region

Clarke, D. Barrie; Cameron, B. I.; Muecke, G. K.; Bates, J.L.

doi:10.1139/e89-077

Cited by 15 publications

(3 citation statements)

References 28 publications

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“…(Ntaflos and Richter 2003), Cretaceous flood basalts of Isachsen Formation (IF) and of Strand Fiord Formation (SFF) from Ellesmere and Axel Heiberg islands (Estrada and Henjes-Kunst 2004), Hansen Point volcanics of northwest Ellesmere Island (HPv), Kap Washington basalts (KWb, light shading) and rhyolites (KWr, dark shading) from North Greenland (Estrada et al 2001), West Greenland picrites (Holm et al 1993), Baffin Island and West Greenland basalts (Clarke et al 1989, and references therein), East Greenland basalts (NE: Thirlwall et al 1994;SE: Holm 1988). Also shown are fields for ocean-island basalts (OIB; Wilson 1989), North Atlantic MORB as well as Iceland Tertiary and recent basalts (Holm et al 1993, and references therein).…”

Section: Discussionmentioning

confidence: 99%

Paleocene alkaline volcanism in the Nares Strait region: evidence from volcanic pebbles

Estrada

Henjes‐Kunst

Melcher

et al. 2009

Int J Earth Sci (Geol Rundsch)

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Paleogene sediments in fault-bounded basins on Judge Daly Promontory, northeast Ellesmere Island, Canadian High Arctic, are rich in volcanogenic material. Volcanic pebbles within the Cape Back basin near Nares Strait were studied for their petrography, geochemistry, Sr and Nd isotopes, and geochronology to identify and characterize their parent rock. The pebbles are derived from lava flows and ignimbrites of a continental rift-related, strongly differentiated, highly incompatible element enriched, alkaline volcanic suite, the proposed Nares Strait volcanic suite, which is distinct from other alkaline volcanic suites on the northern coasts of Ellesmere Island and Greenland. 40 Ar/ 39 Ar amphibole and alkali feldspar ages indicate that volcanism was active around 61-58 Ma and was probably contemporaneous with sedimentation resulting in Middle to Late Paleocene age for deposition within the Cape Back basin and the other Paleogene basins on Judge Daly Promontory.

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Section: Discussionmentioning

confidence: 99%

Paleocene alkaline volcanism in the Nares Strait region: evidence from volcanic pebbles

Estrada

Henjes‐Kunst

Melcher

et al. 2009

Int J Earth Sci (Geol Rundsch)

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“…The chemical compositions of whole rocks and matrix glasses from Baffin Island lavas, which are amongst the most MgO‐rich Phanerozoic lavas known, have been extensively discussed previously [ Clarke , 1970; Clarke and Upton , 1971; O'Nions and Clarke , 1972; Francis , 1985; Clarke et al , 1988; Gill et al , 1992; Robillard et al , 1992; Herzberg and O'Hara , 2002; Stuart et al , 2003]. The samples we have analyzed are a subset of those described by Francis [1985] and Robillard et al [1992] and are taken from the porphyritic glassy margins of individual cooling units.…”

Section: Geological Background and Samplesmentioning

confidence: 99%

Mantle heterogeneity during the formation of the North Atlantic Igneous Province: Constraints from trace element and Sr‐Nd‐Os‐O isotope systematics of Baffin Island picrites

Kent

Stolper

Francis

et al. 2004

Geochem Geophys Geosyst

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Sr‐Nd‐Os‐O isotope and major and trace element data from ∼62 Ma picrites from Baffin Island constrain the composition of mantle sources sampled at the inception of North Atlantic Igneous Province (NAIP) magmatism. We recognize two compositional types. Depleted (N‐type) lavas have low 87Sr/86Sri (0.702990–0.703060) and 187Os/188Osi (0.1220–0.1247) and high 143Nd/144Ndi (0.512989–0.512999) and are depleted in incompatible elements relative to primitive mantle. Enriched (E‐type) lavas have higher 87Sr/86Sri (0.703306–0.703851) and 187Os/188Osi (0.1261–0.1303), lower 143Nd/144Ndi (0.512825–0.512906), and incompatible element concentrations similar to, or more enriched than, primitive mantle. There is also a subtle difference in oxygen isotope composition; E‐type lavas are marginally lower in δ18Oolivine value (5.16–4.84‰) than N‐type lavas (5.15–5.22‰). Chemical and isotopic variations between E‐ and N‐type lavas are inconsistent with assimilation of crust and/or subcontinental lithospheric mantle and appear to instead reflect mixing between melts derived from two distinct mantle sources. Strontium‐Nd‐O isotope compositions and incompatible trace element abundances of N‐type lavas suggest these are largely derived from the depleted upper mantle. The 187Os/188Osi ratios of N‐type lavas can also be explained by such a model but require that the depleted upper mantle had γOs of approximately −5 to −7 at 62 Ma. This range overlaps the lowest γOs values measured in abyssal peridotites. Baffin Island lava compositions are also permissive of a model involving recharging of depleted upper mantle with 3He‐rich material from the lower mantle (Stuart et al., Nature, 424, 57–59, 2003), with the proviso that recharge had no recognizable effect on the lithophile trace element and Sr‐Nd‐Os‐O isotope composition. The origin of the enriched mantle component sampled by Baffin Island lavas is less clear but may be metasomatized and high‐temperature‐altered recycled oceanic lithosphere transported within the proto Iceland plume. Differences between Baffin Island lavas and modern Icelandic basalts suggest that a range of enriched and depleted mantle sources have been tapped since the inception of magmatism in the province. Similarities between Baffin Island lavas erupted and those of similar age from East and West Greenland also suggest that the enriched component in Baffin Island lavas may have been sampled by lavas erupted over a wide geographic range.

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“…In the basins along the Labrador margin south of 62°N, the deeper wells encountered volcanic rocks of Early Cretaceous age (the Alexis Formation: Umpleby, 1979;Balkwill et al 1990). In the ocean floor of the southernmost Labrador Sea at 53°20' N, OPD Hole 647 A drilled through oceanic basalts near magnetic anomaly 24, presumably of early Eocene age (Clarke et al 1989). In the Davis Strait between 62°N and 70°N, the deep well AT2-1 ( Fig.…”

Section: A Volcanic Rocksmentioning

confidence: 99%

Depleted and ultradepleted basalt and picrite in the Davis Strait: Paleocene volcanism associated with a transform continental margin

Larsen

Williamson

2020

Geol. Mag.

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Volcanic rocks from the Davis Strait were studied to elucidate the tectonomagmatic processes during rifting and the start of seafloor spreading, and the formation of the Ungava transform zone between Canada and Greenland. The rocks are from the wells Hekja O-71, Gjoa G-37, Nukik-2 and Hellefisk-1, and from dredges on the northern Davis Strait High. Ages range from Danian to Thanetian (dinocyst palynozones P2 to P5, 62.5–57.2 Ma). The rocks are predominantly basaltic, but include picrites on the Davis Strait High. Calculated mantle potential temperatures for the Davis Strait High are c. 1500°C, suggesting the volume of magma generated was large; this is consistent with geophysical evidence for magmatic underplating in the region. The rare earth element patterns indicate residual mantle lithologies of spinel peridotite and, together with Sr–Nd isotopes, indicate melting beneath regionally extensive, depleted asthenosphere beneath a lithosphere of thickness similar to, or thinner than, beneath Baffin Island and distinctly thinner than beneath West Greenland. Some sites include basalts with more enriched compositions. Depleted and enriched basalts in the Hellefisk well show contemporaneous melting of depleted and enriched mantle components in the asthenosphere. The Hekja and Davis Strait High basalts and picrites have unique, ultradepleted compositions with (La/Sm)N < 0.5, (Tb/Lu)N < 1 and Nb/Zr = 0.013–0.027. We interpret these compositions as a product of the melting regime within the Ungava transform zone, where the melting column would be steep-sided in cross-section and not triangular as expected at normal spreading ridges. Magmatism along the transform stopped when the tectonic regime changed from transtension to transpression during earliest Eocene time.

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Early Tertiary basalts from the Labrador Sea floor and Davis Strait region

Cited by 15 publications

References 28 publications

Paleocene alkaline volcanism in the Nares Strait region: evidence from volcanic pebbles

Paleocene alkaline volcanism in the Nares Strait region: evidence from volcanic pebbles

Mantle heterogeneity during the formation of the North Atlantic Igneous Province: Constraints from trace element and Sr‐Nd‐Os‐O isotope systematics of Baffin Island picrites

Depleted and ultradepleted basalt and picrite in the Davis Strait: Paleocene volcanism associated with a transform continental margin

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