小油坑 / Xiaoyoukeng

小油坑是位於台灣北部陽明山國家公園內的一處火山噴氣孔，位於七星山西北麓，海拔約805公尺。 小油坑」是陽明山國家公園內地質活動相當活躍的景觀區。 噴氣孔是火山活動區附近的火山蒸汽出口。通常，水蒸氣和一些火山氣體被釋放。由於缺乏壓力，水在流出之前就已完全轉化為蒸汽。當有更多的水可用，並在土壤中富含火山灰，粘土和其他細顆粒的地方上升到地面時，就會形成溫泉。

Xiaoyoukeng is a post-volcanic fumarole located in Yangmingshan National Park in the north of Taiwan. It is located at the northwestern foot of Qixing Mountain and is about 805 meters above sea level. Xiaoyoukeng is on of the most geologically active scenic areas in Yangmingshan-Nationalpark.
Fumaroles are volcanic steam outlets near volcanic active areas. A fumarole is an opening in earth’s crust, often in the neighbourhood of volcanoes, which emits steam and gases such as carbon dioxide, sulphur dioxide, hydrochloric acid, and hydrogen sulphide. Mostly water vapor and partly volcanic gases are emitted. Due to the lack of pressure, water is completely converted into steam before it flows out.
When more water is available and rises to the surface at a spot where the soil is rich in volcanic ash, clay, and other fine particulates, then mudpots or hotsprings are formed. You can see a mudpot on your way to the platform.
Fumaroles and hotsprings may occur along tiny cracks, along long fissure, or in chaotic clusters or fields. A fumarole field is an area of thermal springs and gas vents where shallow magma or hot igneous rocks release gases or interact with groundwater.

How to get there?
From Yangmingshan Bus Station (陽明山總站) take Bus 108 or 124 to Xiaoyoukeng (小油坑).

Infocenter
The info center nearby contains restrooms and a small convenience store, as well as further information and a small exhibition of Xiaoyoukeng. It is not necessary to visit the infocenter to log this earthcache.