Colton Point State Park - Geology and Climate

Geology and Climate

Although the rock formations exposed in Colton Point State Park and the Pine Creek Gorge are at least 300 million years old, the gorge itself formed about 20,000 years ago, in the last ice age. Pine Creek had flowed northeasterly until then, but was dammed by rocks, soil, ice, and other debris deposited by the receding Laurentide Continental Glacier. The dammed creek formed a lake near what would later be the village of Ansonia, and the lake's glacial meltwater overflowed the debris dam, reversing the flow of Pine Creek. The creek flooded to the south and quickly carved a deep channel on its way to the West Branch Susquehanna River.

The park is at an elevation of 1,637 feet (499 m) on the Allegheny Plateau, which formed in the Alleghenian orogeny some 300 million years ago, when Gondwana (specifically what became Africa) and what became North America collided, forming Pangaea. Although the gorge and its surroundings seem to be mountainous, the area is a dissected plateau. Years of erosion have cut away the soft rocks, forming the valleys, and left the hardest of the ancient rocks relatively untouched on the top of sharp ridges, giving them the appearance of "mountains".

The land on which Colton Point State Park sits was once part of the coastline of a shallow sea that covered a great portion of what is now North America. The high mountains to the east of the sea gradually eroded, causing a buildup of sediment made up primarily of clay, sand and gravel. Tremendous pressure on the sediment caused the formation of the rocks that are found today in the Pine Creek drainage basin: sandstone, shale, conglomerates, limestone, and coal.

Five major rock formations present in Colton Point State Park are from the Devonian and Carboniferous periods. The youngest of these, which forms the highest points in the park and along the gorge, is the early Pennsylvanian Pottsville Formation, a gray conglomerate that may contain sandstone, siltstone, and shale, as well as anthracite coal. Low-sulfur coal was once mined at three locations within the Pine Creek watershed. Below this is the late Mississippian Mauch Chunk Formation, which is formed with grayish-red shale, siltstone, sandstone, and conglomerate. Millstones were once carved from the exposed sections of this conglomerate. Together the Pottsville and Mauch Chunk formations are some 300 feet (91 m) thick.

Next below these is the late Devonian and early Mississippian Huntley Mountain Formation, which is made of relatively soft grayish-red shale and olive-gray sandstone. This is relatively hard rock and forms many of the ridges. Below this is the red shale and siltstone of the Catskill Formation, about 760 feet (230 m) thick and some 375 million years old. This layer is relatively soft and easily eroded, which helped to form the Pine Creek Gorge. Cliffs formed by the Huntley Mountain and Catskill formations are visible north of the park at Barbour Rock. The lowest and oldest layer is the Lock Haven Formation, which is gray to green-brown siltstone and shale over 400 million years old. It forms the base of the gorge, contains marine fossils, and is up to 600 feet (180 m) thick.

The Allegheny Plateau has a continental climate, with occasional severe low temperatures in winter and average daily temperature ranges of 20 °F (11 °C) in winter and 26 °F (14 °C) in summer. The mean annual precipitation for the Pine Creek watershed is 36 to 42 inches (914 to 1,070 mm). The highest recorded temperature at the park was 104 °F (40 °C) in 1936, and the record low was −30 °F (−34 °C) in 1934.