Pituffik Titanium Project: Results of 2016 Fieldwork. Offshore vibrocore sampling and core logging

Ole Bennike, Maja Bar Rasmussen, Samuel Weatherley

Publikation: Bog/rapportRapport (offentligt tilgængelig)

Abstrakt

A sampling programme using vibrocorers was conducted in July and August 2016 in the Moriusaq area of the Wolstenholme Fjord. The aim was to sample and map potential off-shore heavy mineral deposits. The work was conducted by GEUS for FinnAust Mining Plc.

The work was based on results from a combined echo sounding, C-boom and grab sample survey that was carried out in August 2015 (Jensen & Rödel 2015). The echo sounding work resulted in a detailed bathymetric map of the area. The high-resolution C-boom data resulted in a detailed map showing sediment thickness in the investigated area. The C-boom data were interpreted – in connection with a glacio-isostatic adjustment model for the region – to indicate the occurrence of drowned lowstand and transgressive seismic units that could hold potential heavy mineral black sand resources deposited in drowned beaches. This interpretation needed to be tested by coring.

Vibrocoring in 2016 was conducted along a 30 km long stretch of coast line from a coring pontoon platform in water depths between 0 and 6 metres, and from the vessel M/S Kisaq in deeper waters. In shallow waters penetration was limited, whereas penetration was better in deeper waters. This probably reflects the long fetch to the south-west, which result in fine-grained sediments being transported from shallow waters to deeper waters during storms.

The lengths of retrieved cores typically fall in the range 0.25–1.9 m. About half of the vibrocores were extruded in the field, and about half cores were kept in the core tubes. The extruded sediments were described briefly in the field, whereas the non-extruded sediment cores were shipped to GEUS, where the cores were split lengthwise, logged and photographed.

The vibrocorer we used was a light-weight system (see below) that could be operated by hand from a coring platform or with the crane from M/S Kisaq. The maximum length of core recovered from any locality was 1.98 m. For deeper penetration heavier equipment is needed, or an alternative technique such as sonic drilling could be used.
OriginalsprogEngelsk
UdgivelsesstedCopenhagen
ForlagGEUS
Rekvirerende organisationFinnAust Mining Plc
Antal sider195
Vol/bind2016
DOI
StatusUdgivet - 13 feb. 2017

Publikationsserier

NavnDanmarks og Grønlands Geologiske Undersøgelse Rapport
ForlagGEUS
Nr.68
Vol/bind2016

Emneord

  • Greenland

Programområde

  • Programområde 4: Mineralske råstoffer

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