SEDIMENTOLOGY AND STRATIGRAPHY OF THE UPPER ORDOVICIAN BLACK RIVER AND TRENTON GROUPS, WELLS OUTLIER, ADIRONDACK MOUNTAINS, NEW YORK
The Black River and Trenton Group interval at Wells is correlative to the sequences exposed at Crown Point Peninsula, NY and Roaring Brook, NY and cored intervals in the Mohawk Valley. Carbonate facies typical of the Lowville and Chaumont Formations of the Black River Group, and the Napanee and Kings Falls Formations of the Trenton Group, are present in the Wells exposures. The Black River and Trenton carbonate sequence includes coarse siliciclastic sand intervals and angular cobbles and pebbles of local basement lithologies are present. Carbonate clast breccias within the sequence also suggest syndepositional faulting. The interval at Wells includes the M3-M4 depositional sequence boundary (Brett et al., 2004) and a prominent calcitized K-bentonite tentatively identified as the M/H K-bentonite (Cornell, 2008). U-Pb geochronological analyses of zircon from the bentonite are underway.