Park Avenue — Before an Arch, There Is a Fin
Listen at the stop, then read the transcript and follow the sources behind the story.
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Transcript
Park Avenue contains few complete arches, which makes it an ideal first stop. The tall walls and fins show the stage that often comes before an arch forms.
Deep underground, thick salt deposits deformed and collapsed, bending the sandstone above. Uplift and expansion produced parallel fractures. Erosion then removed material along those cracks, leaving long narrow fins.
Water is crucial. It enters pores and fractures, dissolves mineral cement and widens weaknesses during freeze-thaw cycles. Wind helps remove loose grains, but the popular idea that arches are mainly “wind carved” is misleading.
Walk through Park Avenue mentally as a quarry of future possibilities. Most fins will never become famous arches. Some will open, some will collapse, and all are temporary. The park’s architecture begins with fracture, not with a finished curve.