Editing Delaware Water Gap (section)

==Geology==
[[Image:WorthingtonStateForest.jpg|thumb|[[Worthington State Forest]] seen from a campsite]]
[[File:Del Water Gap.jpg|thumb|The Delaware Water Gap with the [[Pennsylvania]] [[Delaware Water Gap, Pennsylvania|town of the same name]] visible in the lower left next to the [[Interstate 80 in Pennsylvania|I-80]] crossing.]]

A water gap is a geological feature where a river cuts through a mountain ridge. The Delaware Water Gap formed 500 [[Mya (unit)#Symbols y and yr|million years ago]]<ref>{{Cite web |date=2019-06-28 |title=Delaware Water Gap |url=https://appalachiantrail.org/delaware-water-gap/ |access-date=2022-06-21 |website=Appalachian Trail Conservancy {{!}} |archive-date=2022-06-24 |archive-url=https://web.archive.org/web/20220624230705/https://appalachiantrail.org/delaware-water-gap/ |url-status=live }}</ref> when quartz pebbles from mountains in the area were deposited in a shallow sea. The [[Martinsburg Shale]] on the eastern side of what was to be Kittatinny Mountain was uplifted 450 million years ago when a chain of volcanic islands collided with proto-North America. These islands slid over the North American plate, and deposited rock on top of the plate, forming the Highlands and Kittatinny Valley.

About 400 million years ago, [[Avalonia|a small continent]] collided with proto-North America. The heat from the pressure melted the quartzite, which allowed it to bend the quartz pebbles. This layer was then uplifted and cracked over thousands of years. During this period, the Delaware River slowly cut its path down through the shattered and cracked quartzite. If the quartzite had not been cracked, the river would not have been able to cut its path through the mountain to form the gap.<ref>{{Cite web |url=https://www.nps.gov/dewa/learn/nature/upload/How-the-gap-is-formed.pdf |title=Delaware water Gap National Recreation Area, The geology of the Delaware Water Gap |access-date=2020-04-29 |archive-date=2020-10-21 |archive-url=https://web.archive.org/web/20201021082957/https://www.nps.gov/dewa/learn/nature/upload/How-the-gap-is-formed.pdf |url-status=live }}</ref>

Millions of years of rain, ice, snow, and wind erosion shaped the area. The [[Wisconsin glaciation]], which occurred between 21,000 BCE and 13,000 BCE, covered the entire Kittatinny Ridge and ended near Belvidere. When the glaciers retreated, the existing gap assumed its present form.<ref>{{Cite web |title=Wisconsin Glacial Stage {{!}} Time, Map, & Facts {{!}} Britannica |url=https://www.britannica.com/science/Wisconsin-Glacial-Stage |access-date=2022-06-21 |website=www.britannica.com |language=en |archive-date=2022-06-21 |archive-url=https://web.archive.org/web/20220621005024/https://www.britannica.com/science/Wisconsin-Glacial-Stage |url-status=live }}</ref>

The mountain is composed of Silurian [[Shawangunk Formation|shawangunk]] [[Conglomerate (geology)|conglomerate]]. This is gray quartzite, which makes the mountain highly resistant to weathering. The Silurian High Fall formation of sandstone is on the western side of the gap near the base. The eastern side of the gap has [[Ordovician]] Martinsburg shale. Sedimentary rock is along the river. The Bloomsburg Red Beds, a red shale, are at the gap under Dunnfield Creek.

The Delaware Water Gap is nearly {{Convert|1300|ft|m}} wide at river level and about {{Convert|1|mi|km}} wide from the top of Mt. Tammany to the top of Mt. Minsi. It is more than {{convert|1200|ft|}} from mountaintop to the river surface.<ref>[https://www.nps.gov/dewa/learn/news/upload/Guide-to-Gap-2022-Final-optimized.pdf Guide to the Gap (nps.gov)]</ref> The river through the gap is {{Convert|290|ft|m}} above sea level.

The ridge of the [[Appalachian Mountains|Appalachians]] that the Delaware River crosses is called the [[Blue Mountain (Pennsylvania)|Blue Mountains]] in Pennsylvania and the [[Kittatinny Mountains|Kittatinny Ridge]] in [[Warren County, New Jersey]]. This is the first major ridge of the Appalachian mountains. New Jersey's mountain is [[Mount Tammany]], named after the [[Lenape|Lenni-Lenape]] [[Tamanend|Chief Tamanend]]. The Pennsylvania mountain is [[Mount Minsi]], named after the [[Munsee|Native American tribe]] of the area. The summit of Tammany is {{convert|1540|ft|m|-1|abbr=on}} above sea level.