The Daguoye Columnar Basalt sits on the shoreline of Daguoye Village, Xiyu Township, Penghu. It is the most representative volcanic geological site in the Penghu archipelago and one of Taiwan’s most accessible columnar basalt formations. Around 16 million years ago, the area was subjected to intense volcanic activity. As the basaltic lava erupted and cooled, thermal contraction naturally produced the distinctive hexagonal columnar jointing — a classic case study in earth science. Over millions of years of wave erosion and weathering, these ancient rock formations, once buried underground, have been progressively exposed, making them the centerpiece of the Penghu Geopark. Today the site draws geology enthusiasts, student field-trip groups, and travellers who want to understand how volcanic history shaped Penghu’s landscape.
Highlights
The formation is noted for its hexagonal basalt columns standing approximately 10 metres tall, each with a uniform side length of about 50 centimetres — arranged in such orderly rows that they almost appear to have been cut by hand. On close inspection, the column surfaces show honeycomb-like cavities formed by prolonged marine erosion, and the gaps between columns have been scoured into deep horizontal grooves by wave action — both reflecting differences in basalt density and resistance to erosion. Cross-sections of the cliff face reveal light and dark banding created by varying cooling rates, while the intertidal zone below exposes a network of eroded landforms. During the winter northeast monsoon season, waves surge into the joints and along the central axes of the columns, producing a deep rumbling sound — the combined visual and acoustic effect is striking. Looking closely at the columns, the jet-black basalt contains scattered magnetite grains. These magnetic minerals recorded the direction of Earth’s magnetic field tens of millions of years ago and are invaluable to palaeomagnetic researchers studying Earth’s history.
Getting There & Nearby
Chima bus stop is about a 10-minute walk from the site entrance. If driving, the Xiyu Township public car park is approximately 200 metres away on foot. Yunxiang Temple is located next to the car park and has toilet facilities — a convenient stop before heading to the site. Nearby attractions include Xiaomen Whale Cave (about 5 minutes by car), where northeast monsoon-driven geological formations can be observed, and Wai-an Fishing Port (about 8 minutes by car), with its traditional fishing harbour. Both can be combined into a day trip. The Xiyu bus route connects all the major sights along the way, including the Xiaomen Geology Hall and the Erkan traditional settlement. Taking the bus around Xiyu is a practical way to explore multiple cross-sections of Penghu’s volcanic geology and local cultural heritage in a single outing.