Description

Services to be provided: · Crushing of supplied samples to -40+60 mesh (or equivalent). · Ultrasonic cleaning in appropriate reagents of the -40+60 mesh fraction and the removal of biotite and hornblende (and muscovite if present) from this grain size fraction for each sample. · Some rocks are considered to be Proterozoic (ca. 1900 Ma) and therefore a suitable number of grains of each respective mineral type must be irradiated for an appropriate time interval in a monitored neutron flux. · Some rocks are considered to be Paleozoic and/or Cretaceous and therefore a suitable number of grains of each respective mineral type must be irradiated for an appropriate time interval in a monitored neutron flux. · Incremental heating (8-10 gas-steps per specimen) of each mineral separate. · Analysis of the exsolved, cleaned gas for its 40Ar-39Ar age, corrected appropriately for interfering isotopes. · by March 31, 2007, a report on scientific findings in a format to be agreed upon with the contract authority. Samples and minerals to be dated: 1) South Wopmay Bedrock Mapping Project (Proterozoic): - 5 granitic rocks – hornblende + biotite ± muscovite - 1 granitic rock – biotite ± muscovite - 2 ultramafic rocks – phlogophite 2) Mactung (Paleozoic and/or Cretaceous) - 10 samples for biotite ± muscovite Bidders are requested to provide information on cost per sample or mineral, plus any other technical information that may be required to fully evaluate bids (e.g., deviations from standard methodology).