BEDROCK SOURCES OF PLACER GOLD-MERCURY AT THE WITLAGE CREEK PROSPECT, EASTERN SURINAME, SOUTH AMERICA

The highly productive and historic Witlage Creek gold placer has been worked since the early 1900's by small scale miners or porknockers. Too, the headwaters were prospected for mercury in both the early 1900's and 1950's due to the occurrence of large cinnabar nuggets in Witlage Creek. Recent exploration identifies at least three bedrock sources at the head of the Witlage Creek drainage for the NE-striking Witlage Creek placer gold and mercury. Exploration techniques included geologic mapping (1:10,000 scale, ~ 20 km²), stream panning, and geochemical sampling of rocks and soils (saprolite and ferricrete). In addition to gold, stream sediment concentrates include cinnabar, native mercury, magnetite, pyrite, specular hematite, garnet, pyrolusite, schorl tourmaline, rutile, ilmenite, goethite, leucoxene, gibbsite, kaolinite, diaspore, and paragonite.

Generally these greenschist-grade metamorphic rocks form a series of north- to northwest-striking folds that are overturned to the west-southwest. Bedding planes are transposed into the regional foliation and fold limbs and fold axes dip isoclinally to the northeast. The uppermost drainage of Witlage placer follows a synclinal axis and then the western contact of a plunging anticline that turns to the northeast and into the main placer.

In one area, gold and mercury are associated with a contact between metamorphosed mafic rocks and overlying arenites and litharenites along the southwestern limb of a northwest-striking anticline. Gold and mercury values are highest at the contact and are most disseminated in the sediments. Gold in the mafic rocks is associated with trace platinum, anomalous iron (up to detection limits of 25 %), phosphorus, and titanium. Native mercury is common in the mafic rocks and discontinuous cinnabar-pyrite-gold veins are along the contact.

In a second area, vein gold is hosted by an andesite within an east-west striking 400 by 1000 m zone of stockwork quartz veining, alteration, and anomalous arsenic. Vein minerals include pyrite, pyrrhotite?, and visible gold.

In a third area, gold values are near the contact of an intrusive gabbro within the axis of the anticline of the first area.