Site: Lamont-Doherty Earth Observatory, Palisades, NY

Well: Lamont Test Well 4 (TW-4)

Total depth: 1802 ft (549.2 m)

TW-4 is located on the campus of the Lamont-Doherty Earth Observatory of Columbia University in Palisades NY. The well penetrated the outcropping Palisades Sill, the underlying sedimentary strata of the Newark Basin, and the crystalline basement below the basin.

The drilling was conducted in 3 phases:

- 0-646 ft (0-196.9 m), all within the Palisades Sill, were drilled without coring

- 646-750 ft (196.9-228.6 m) were drilled and cored using a 4.88-in wide (~12.4 cm) PQ diamond bit. The first sediments below the sill were encountered at a depth of 691 ft (210.6 m). At 750 ft (228.6 m) the drilling stopped, and the hole was cased and cemented in order to protect shallow aquifers.

- 750-1802 (228.6-549.2 m) were drilled and cored with a 3.84-in wide (9.8 cm) HQ bit. The crystalline basement was penetrated at a depth of 1711 ft (521.5 m. Core recovery was close to 100% (1156 ft, or 352 m of core collected), with only a few narrow zones of rubble.

Core photos

York State Geological Survey) during the drilling and coring of TW-4 by the TriCarb Consortium for Carbon Sequestration. The core depth from ground level is marked on the core every foot.