Scoria is a highly vesicular, dark-colored volcanic rock that may or may not contain crystals (phenocrysts). It is typically dark in color, and basaltic or andesitic in composition. Scoria is relatively low in density as a result of its numerous macroscopic ellipsoidal vesicles, but in contrast to pumice, all scoria has a specific gravity greater than 1, and sinks in water. The holes or vesicles form when gases that were dissolved in the magma come out of solution as it erupts, creating bubbles in the molten rock, some of which are frozen in place as the rock cools and solidifies. Scoria may form as part of a lava flow, typically near its surface, or as fragmental ejecta, for instance in Strombolian eruptions that form steep-sided scoria cones. Chemical analysis of scoria found in Yemen showed that it was mainly composed of volcanic glass with a few zeolites. Most scoria is composed of glassy fragments and may contain phenocrysts. The word scoria comes from the Greek σκωρία, skōria, rust. A colloquial term for scoria is cinder.
The Auckland volcanic field is an area of monogenetic volcanoes covered by much of the metropolitan area of Auckland, New Zealand's largest city, located in the North Island. The approximately 53 volcanoes in the field have produced a diverse array of maars, tuff rings, scoria cones, and lava flows. With the exception of Rangitoto, no volcano has erupted more than once, but eruptions lasted for various periods ranging from a few weeks to several years. Rangitoto erupted twice; the first eruption occurred about 600 years ago, followed by a second eruption approximately 50 years later. The field is fuelled entirely by basaltic magma, unlike the explosive subduction-driven volcanism in the central North Island, such as at Mount Ruapehu and Lake Taupō. The field is currently dormant, but could become active again.
Penshurst is a town in Victoria, Australia. It is in the Shire of Southern Grampians local government area and is located at the foot of Mount Rouse, an extinct volcano. At the 2006 census, Penshurst had a population of 461. Basic facilities include a hospital with an aged care residency and doctor's surgery, a pub, a hall and two schools – one a State school, the other a Catholic school – the State school has 10 students(2020), the Catholic school 26.
Beveridge is a town in Victoria, Australia, located along the Hume Highway, 42 kilometres north of Melbourne. It is governed by the Mitchell Shire. At the 2016 Census, Beveridge had a population of 2,330.
Tower Hill is an inactive volcano on the south-west coast of Victoria, Australia, approximately 275 kilometres (171 mi) west of Melbourne, and 15 kilometres (9 mi) north-west of Warrnambool. The Tower Hill crater is roughly 3 kilometres (2 mi) wide and 80 metres (260 ft) high, with a gradient of between 10% to 80% at the higher points. Within the crater, a series of later volcanic explosions formed a number of scoria cones and spheres, surrounded by a crater lake. Being a giant nested maar, Tower Hill is of international geological significance. The Dhauwurdwurrung name for the volcano is Koroitj.
Mount Quincan is a volcanic mountain near Yungaburra on the Atherton Tableland in Far North Queensland, Australia.
Mount Elephant is a 380-metre-high (1,250 ft) conical breached scoria cone formed by a dormant volcano, located 1 km from the town of Derrinallum in southwestern Victoria, Australia. It is a prominent landmark that forms the eastern gateway to the Kanawinka Geopark from the Hamilton Highway at Derrinallum.
Mount Noorat is a dormant volcano, situated on Glenormiston Road north of the township of Noorat, and approximately six kilometres north of Terang, Victoria, Australia. The last eruption is estimated to have occurred between 5,000 and 20,000 years ago.
Mount Leura is a 313-metre scoria cone surrounding a dry crater 100 m deep and is the central and most obvious component of a larger volcanic complex southeast of the town of Camperdown located in western Victoria, Australia, 194 kilometres (121 mi) south west of the state capital, Melbourne. The inactive volcano is thought to have last erupted between 5,000 and 20,000 years ago. The name means "big nose" in local aboriginal dialect.
Mount Porndon is a 278-metre-high (912 ft) volcano located 13 kilometres southeast of Camperdown in western Victoria, Australia.
Budj Bim, also known as Mount Eccles, is a dormant volcano near Macarthur in southwestern Victoria, Australia. It lies within the geologically-defined area known as the Newer Volcanics Province, which is the youngest volcanic area in Australia and stretches from western Victoria to south-eastern South Australia.
Mount Cambria is one of the volcanoes in the Auckland volcanic field. Located in the suburb of Devonport north-east of Mt Victoria, its 30-metre scoria cone was quarried away. The site is now Cambria Reserve. It was named Heaphy Hill after Charles Heaphy by Ferdinand von Hochstetter in 1859, but this name is not used.
Waitomokia is a volcano in the Auckland volcanic field. Waitomokia's 600 m (2,000 ft) wide tuff crater contained three small scoria cones up to 20 m (66 ft) high, one with a crater, which were quarried in the 1950s.
Maungataketake is one of the volcanoes in the Auckland volcanic field in New Zealand. It had a 76 m high scoria cone, beside a 100 m wide crater, before they were quarried away. It was the site of a pā. Layers of volcanic tuff and ash from Maungataketake overlay the fallen trunks of the nearby Ihumātao fossil forest. The New Zealand Ministry for Culture and Heritage gives a translation of "broad mountain" for Maungataketake.
Purchas Hill is one of the volcanoes in the Auckland volcanic field.
McLennan Hills is one of the volcanoes in the Auckland volcanic field. It was a group of cratered scoria mounds up to 45 m high, before it was quarried away. A 1940 aerial photo shows a crater around 100 m wide, one around 50 m wide, and 2 or 3 smaller craters. McLennan Hills, alongside neighbouring Ōtāhuhu / Mount Richmond, were the sites of fortified pā in pre-European times, important due to their location between the Waitematā Harbour/Tamaki River and the Manukau Harbour. Since the European settlement of Auckland, the scoria cone was quarried. The former quarry site was used for greenhouses before being redeveloped for housing.
Maungawhau / Mount Eden is a scoria cone in the Mount Eden suburb of Auckland, New Zealand.
Maungarei / Mount Wellington is a 135-metre volcanic peak located in the Auckland volcanic field of Auckland, New Zealand. It is the youngest onshore volcano of the Auckland volcanic field, having been formed by an eruption around 10,000 years ago. It is the largest of Auckland's scoria cones and has a near-circular base with a flattish rim and three small craters. It is situated in the Mount Wellington suburb of East Auckland.
Te Tātua-a-Riukiuta is a volcano in Three Kings, New Zealand that erupted 28,500 years ago. The volcano had three prominent peaks and a number of smaller peaks until most of them were quarried away, leaving a sole remaining large peak called Big King.
Mount Kooroocheang, also known as Smeaton Hill, is a dormant volcano, situated near the town of Smeaton, Victoria, Australia. It is about 140 km northwest of Melbourne. It is a large composite scoria cone. Mount Kooroocheang is one of the largest eruption points on the Victorian Central Plateau, and is about 230 metres in height above the surrounding plains and 676 metres above sea level. There is a communications tower on the summit.
