Shimen Cave Introduction
Shimen Cave, standing along the Coastal Highway Taiwan Provincial Highway No. 2, is a prominent landmark in Shimen District, New Taipei City. The name originates from this cave, which amazed the Japanese during the colonial era with its unique coastal erosion landform, leading them to name the area "Shimen Village," a name that has since been retained in local use. Geologically, it is officially referred to as a "sea arch," formed by marine erosion. Millions of years ago, the Datun Volcano Group erupted, accumulating thick layers of volcanic debris and lava. Over time, heavy rains eroded these layers along the coastline, creating a small hill. The processes of tectonic pressure further split the rock into vertical "joints," or fractures. Coupled with the northeast monsoon and frequent summer typhoons, intense waves exerted strong erosive energy, causing the sea to continuously batter and erode the joints and layers, resulting in portions of the rock collapsing into the sea. Over time, what began as a sea erosion trough evolved into a sea cave and ultimately transformed into the sea arch we see today. Although formed through marine erosion, Shimen Cave is noticeably elevated above sea level due to recent tectonic movements that have raised the land, making it stand more than ten meters above sea level, a testament to the earth's dynamic changes. Upon closer inspection inside Shimen Cave, one can observe clearly stacked layers of rock, each containing fine sand, volcanic debris, and gravel of varying sizes mixed together. This indicates that the accumulation of rock layers likely occurred due to landslides triggered by heavy rains, where the fast-moving debris carried both large rocks and fine sand to the foot of the hill before they could settle individually, resulting in the mixed deposits of fine sand and gravel seen today. In terms of natural ecology, stepping into Shimen Cave reveals breathtaking views where the sea meets the sky. Although it features only a small, beautiful shell-sand beach, it evokes thoughts of Kenting. The shallow coastal reefs are home to numerous fish and hermit crabs. The coastal rocks, adorned with seaweed, display a vibrant green, and sometimes local residents can be seen harvesting algae. Continuing along the coastal walkways and observation platforms offers even more expansive views of the ocean. Each year, between April and May, Taiwan's native lilies and stone vegetables bloom, decorating the area above Shimen Cave, creating a spectacular sight. A visit to Shimen Cave provides an opportunity to experience diverse ecosystems, revealing the rich natural beauty along the shores of Shimen.
