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of the folds, faults, joints and cleavage formed during three periods
of mountain building. About 650 million years ago, during the
Late Proterozoic, the granite and gneiss now making up the New
Jersey Highlands were part of an ancient continent called Rodinia.
About 540 million years ago, powerful tectonic forces began
pulling the landmass apart. As the continental crust thinned and
stretched, elongate rift valleys were formed. As time went on, the
rifts widened and deepened, and flooded with sea water, eventually
forming new oceanic basins. Finally, tectonic activity along the
coast subsided. Carbonate sediments were deposited along an
eastward facing shoreline of a warm shallow sea until about 480
million years ago. During this time, about 3000 feet of material
accumulated; it now makes up the carbonate rock that underlies
10 74o 75o 41o 45’ PA NY
Mesozoic rift basins High
Point Carboniferous and Permian rocks 41o NY
NJ 41o Silurian and Devonian rocks
Cambrian to middle Ordovician rocks
of the early Paleozoic continental shelf
Early Cambrian to middle Ordovician
transported rocks of ancient North American
continental slope and rise Pa 40o 15’ NJ 0 16
miles Proterozoic metamorphic and plutonic rocks Figure 9. Regional geologic map of the area surrounding High Point State Park. part of Kittatinny Valley.
About 460 million years ago the ocean basin began to close and
a period of mountain building, called the Taconic Orogeny, began.
During its initial stages, the North American plate collided with
several smaller plates. This collision caused uplift and erosion of
the carbonate rocks. A downwarping followed that submerged the
land beneath the sea. Folding, faulting and a westward pushing
and stacking of the rocks and sediments in the collision zone
formed a mountain chain. Over time the mountains were lowered
by erosion, the weathering products of clay, silt, and sand were
carried westward by rivers and ocean currents to a deep ocean
basin. These materials thickened, compacted and became the
shale, siltstone and sandstone of the Martinsbu...
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