GEOSCAN, résultats de la recherche


TitrePetrology, Mineralogy and Geochemistry of the Musquodoboit E-23 well, Scotian Shelf
AuteurPe-Piper, G; MacKie, H; Piper, D J W
SourceCommission géologique du Canada, Dossier public 6281, 2009, 88 pages, (Accès ouvert)
ÉditeurRessources naturelles Canada
Documentdossier public
Mediaen ligne; numérique
ProvinceRégion extracotière de l'est
Lat/Long OENS-61.0000 -60.5000 44.0833 43.9167
Sujetsfaciès diagénétiques; diagenèse; Crétacé inférieur; pétrographie; puits; pétrologie du sediment; interprétations géochimiques; minéraux détritiques; géochimie des roches totales; carottes; lithologie; grès; Puit Musquodoboit E-23 ; Formation d'Abenaki ; Membre de Baccaro ; 6; minéralogie; sédimentologie; géochimie; géologie marine; Mésozoïque; Crétacé
Illustrationslocation maps; tables; stratigraphic columns; photographs; ternary diagrams; plots
Diffusé2009 12 07
Résumé(disponible en anglais seulement)
Large cuttings samples were collected from key horizons at the time of drilling the Musquodoboit E-23 well. Most of the samples studied in detail were from the Logan Canyon and Missisauga formations. Single-lithology chips were separated from these cuttings and the samples that were large enough were analyzed geochemically for major and trace elements. Heavy minerals and lithic fragments were separated with tetrabromoethane and the compositions of heavy minerals including tourmaline, chromite and garnet were determined by electron microprobe.
Mudstone samples from the Logan Canyon and Missisauga formations are geochemically similar among themselves and resemble mudstones from the nearby Alma field. A muddy sandstone from the basal Banquereau Formation is geochemically distinct. The Logan Canyon and Upper Missisauga formations have a much higher proportion of low-Mg tourmaline, characteristic of a granitic source, than the Middle Missisauga Formation, in which tourmaline of metamorphic origin predominates. The absence of low-Mg tourmaline in the Glenelg and North Triumph fields suggests that this mineral was supplied by a Chaswood Formation river crossing central Nova Scotia from New Brunswick. Near the base of the Middle Missisauga Formation, many of the analyzed garnets closely match analyses from both the South Mountain batholith and Meguma Group metasedimentary rocks, but similar garnets are rare at higher stratigraphic levels. Tremolite and low-Fe diopside are each present at two horizons in Musquodoboit E-23, but have not been recognised elsewhere in the Lower Cretaceous of the Scotian basin, from which we have more than 4000 electron microprobe analyses of detrital minerals. They are sourced from thermally metamorphosed impure limestones, possibly from the inner Scotian Shelf. Lower Cretaceous sediments in Musquodoboit E-23 were supplied principally by a large Cabot Strait river that brought sediment to the entire Sable sub-basin. Detrital minerals provide some evidence for lesser local supply of sediment from the rivers that deposited the Chaswood Formation of central Nova Scotia.