TECTONIC AND STRUCTURAL CONTROLS OF PREHISTORIC CHERT QUARRIES AND ASSOCIATED ARCHAEOLOGICAL SITE COMPLEXES

Geologic mapping of the Hamburg 7.5' Quadrangle infers three structural domains; an eastern normal fault section, a central section of northwest verging, synthetic thrust ramps and a western section of antithetic thrust faults.

Normal faults down dropped Neoproterozoic-Cambrian Hardyston and Cambrian Leithsville and Limeport formations into linear grabens. Thrust ramps brought Cambrian Limeport and Upper Allentown and Ordovician Stonehenge formations to the surface. Antithetic thrust faults exposed the Ordovician Rickenbach, Epler and Ontelaunee formations.

The structural style of the quadrangle defines prehistoric chert quarry distribution. Prehistoric quarries in the normal fault section occur as linear outcrops and elliptical mounds of chert on topographic benches; with associated dolomite springs and well-drained soils on structural benches above extensive wetlands. Quarries are exhausted of their raw material and mapping infers that the quarries are a community type with a generalized inventory of mining instruments. Occupation sites in close proximity to the quarries were inhabited intermittently over a long cultural period.

Thrust ramp quarries are small, poorly developed, irregular in outline and occur in poorly drained, lower elevations. Quarry technology is weakly defined and curated mining instruments occur in low frequencies.

Antithetic thrust quarries occur as linear bands at high elevations along drainage divides, in close proximity to small wetlands and springs. Quarries are extensive architectural features where task subdivision is rigidly defined. Mining instrument inventory is complex, fashioned from various metamorphic rocks. Although rock shelters are plentiful, the antithetic thrust section has few large sites.

These observations support the interior lakes model of prehistoric site development. This model includes quarries that occur in close association with aquatic resources, such as the quarries in the normal fault section. The thrust ramp quarries may have been exploited by hunting, fishing and trapping parties along travel routes in areas of temporary stays, small base camps and specialized activity sites. These quarries may have provided chert for subsistence needs and served as a location for sociotechnic and ideological activities.