Mount Rishiri ( 利尻山 , Rishiri-zan ) is a Quaternary stratovolcano located off the coast of Hokkaidō , Japan in the Sea of Japan . It rises out of the Sea of Japan forming Rishiri Island . Because its cone shape resembles Mount Fuji it is sometimes referred to as Rishiri Fuji. It is one of the 100 famous mountains in Japan .
5-526: Mount Rishiri's opening festival is held annually on July 2 and July 3. This festival officially opens the climbing season. Mount Rishiri is made up of alkali and non-alkali mafic volcanic rock dating from the Late Pleistocene , 130,000–18,000 years ago. Otherwise it is covered in Quaternary volcanic rock debris. The ascent of Rishiri is challenging in places and not suitable for novice hikers. There
10-452: Is a stub . You can help Misplaced Pages by expanding it . Alkali basalt Alkali basalt or alkali olivine basalt is a dark-colored, porphyritic volcanic rock usually found in oceanic and continental areas associated with volcanic activity, such as oceanic islands , continental rifts and volcanic fields . Alkali basalt is characterized by relatively high alkali (Na 2 O and K 2 O) content relative to other basalts and by
15-518: Is a campsite partway up the mountain from the dock, and an unmanned hut located a short distance below the summit. There is also a small shrine at the summit. On clear days the view extends to Hokkaidō, the adjacent island of Rebun, and as far as Sakhalin Island in Russia . The package of Shiroi Koibito cookies includes a picture of Mount Rishiri arranged in the centre. This Hokkaidō location article
20-710: Is mainly composed of olivine, titanium-rich augite and plagioclase feldspar and may have alkali feldspar or feldspathoid interstitially, but is poor in silica minerals, such as hypersthene and quartz . Phenocrysts are ubiquitous in alkali basalt and, similarly to the groundmass, are usually made up of olivine and titanium-rich augite but can also have plagioclase and iron oxides with lower frequency. Alkali basalt can be found in areas associated with volcanic activity, such as oceanic islands ( Hawaii , Madeira , Saint Helena , Ascension , etc.), continental rifts and volcanic fields. Continental alkali basalt can be found in every continent, with prominent examples being
25-484: The presence of olivine and titanium-rich augite in its groundmass and phenocrysts , and nepheline in its CIPW norm . Alkali basalt is chemically classified as a rock in region B (basalt) of the total alkali versus silica (TAS) diagram that contains nepheline in its CIPW norm. Basalts that do not contain normative nepheline are characterized as sub-alkali basalts , which include tholeiitic basalts and calc-alkaline basalts . The groundmass of alkali basalt
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