Constraints on the age of <i>Archaeozoon acadiense</i> and evidence for hydrothermally transported zircon in the Ashburn Formation (Green Head Group), Saint John, New Brunswick, Canada

Zircon grains from metasiltstone beds in the Precambrian Ashburn Formation were dated to constrain age of stromatolite Archaeozoon acadiense. The largest group analyzed consists mostly well-rounded detrital zircon no younger than 1060 Ma with significant peaks at about 1200–1100, 1500, 1800, 2050, and 2700 Ma, as well a few Mesoarchean ages. A second population apparently euhedral gives ages range 680–400 Ma. distribution along field relationships suggest that Martinon formations are proximal distal parts Green Head Group, respectively, hence previously reported maximum depositional ca. 602 ± 8 for also applies Formation. Paleozoic recovered cannot be because rocks intruded contact metamorphosed by Golden Grove Plutonic Suite 550–525 found four independently processed samples have been seen other studies region, showing they not due laboratory contamination. formed during magmatic activity may transported hydrothermal fluids emplaced into these metasedimentary veins. single an atypically thick vein gave 659 33 Hydrothermally might provide window igneous processes which evidence is otherwise preserved this areas.