Mercury in rocks and minerals of the Skaergaard intrusion, East Greenland

• Main Authors: C. B. Dissanayake, E. A. Vincent
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Greenland; East Greenland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.631.1005; http://www.minersoc.org/pages/Archive-MM/Volume_40/40-309-33.pdf

SUMMARY. Mercury has been determined by radiochemical neutron-activation analysis n nineteen representative rocks from the Skaergaard intrusion and in the separated cumulus minerals of five. The chilled marginal gabbro contains o'23 ppm Hg, values in the Layered Series rocks ranging from o'o7 to o'34 ppm, in one exceptional case reaching I "23 ppm Hg. There is a tendency for mercury to be more abundant in leucocratic than in average or melanocratic rocks at a similar horizon. Some-what higher levels of mercury are found in the granophyric rocks at the top of the intrusion. Apart from a weak and sporadic tendency to be preferentially enriched inplagioclase, the distribu-tion of mercury between the various cumulus phases i fairly uniform and it is thought to occur as uncharged atoms mainly occupying spaces resulting from lattice defects and imperfections rather than in specific structural sites. The distribution pattern of mercury in the intrusion appears to be determined by its high volatility and chemical inertness; no real evidence of any chalcophile character isobserved. MOSTLY due to the lack of reliable analytical data, little is known of the behaviour of mercury in igneous rocks; earlier spectrographic and colorimetric determinations could be regarded at best as semi-quantitative. In the present work, neutron-activation