Lambertville Quarry (Trap Rock Industries Lambertville Quarry; Mt. Gilboa Quarry), Delaware Township, Hunterdon County, New Jersey, USAi

Regional Level Types
Lambertville Quarry (Trap Rock Industries Lambertville Quarry; Mt. Gilboa Quarry)	Quarry
Delaware Township	Township
Hunterdon County	County
New Jersey	State
USA	Country

The Lambertville Quarry is located on Rt. 29 approximately 2 mile north of the center (Bridge Street) of Lambertville, NJ and 300 hundred feet east of the Delaware River in Delaware Township, Hunterdon County, New Jersey. The quarry is one of four operated by Trap Rock Industries in central New Jersey.

The Lambertville Quarry is opened in the lower half of the Mt. Gilboa diabase. The Mt. Gilboa diabase, referred to as the Stockton diabase by some writers (Husch, 1988) is a small, fault bounded segment of the Palisades intrusive complex that includes the Palisades diabase and all the diabase intrusions in the Lambertville-Hopewell-Rocky Hill area of central NJ. The Brookville syenite deposit, (listed as such in Mindat) is located at the upper contact of the Mt. Gilboa diabase with the Lockatong formation and is a few hundred feet north of the Lambertville Quarry’s north face.

The central portion of the Mt. Gilboa diabase is very coarse grained and contains a significant amount of granophyre. In the early to mid 1940’s a very irregular cavity was exposed that contained an axinite group mineral, almost certainly ferroaxinite. The axinite-bearing cavity was described briefly by Tomlinson (1945) who interpreted it as resulting from the concentration of volatiles at the last stages of crystallization of the magma, essentially a miarolitic cavity in diabase pegmatite. The axinite group mineral along with actinolite, prehnite, epidote, tourmaline and datolite occurred in both the open cavity and in more dense, hydrothermally altered granophyre surrounding the open space.

Johnson and McLaughlin (1957) say that the quarry was then operated by the Lambertville Quarry Company. It was the first stop on the Geological Society of America field trip covering the Delaware Valley Triassic section. There are almost certainly other minerals that occur at the Lambertville Quarry, members of the assemblage common in the Newark Basin trap rocks. However, since operation of the quarry was assumed by Trap Rock Industries in the 1960’s it has received little collecting or scientific attention.

Did the axinite deposit result from boron enriched residual fluids associated with the formation of the granophyre or was there a local addition of boron into the magma by the incorporation of Lockatong argillite or did it result from hydrothermal activity subsequent to solidification? So little material has been preserved and such sketchy descriptions have survived that it is difficult to comment with any real certainty on the origin of this axinite occurrence. It is apparently unique in the trap rocks of the Newark Basin.

In Mindat “axinite” is listed for Hunterdon County, New Jersey. The Lambertville Quarry is the actual site of occurrence.

Other Regions, Features and Areas containing this locality

References