When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Cinder Cone and the Fantastic Lava Beds - Wikipedia

    en.wikipedia.org/wiki/Cinder_Cone_and_the...

    Highest point; Elevation: 6,896 ft (2,102 m) NGVD 29 [1] Coordinates: 1]: Geography; Location: Lassen and Shasta counties, California, U.S.: Parent range: Cascade Range: Topo map: USGS Prospect Peak: Geology; Mountain type: Extinct Cinder cone: Volcanic arc: Cascade Volcanic Arc: Last eruption: 1666: Climbing; Easiest route: Trail hike: Cinder Cone is a cinder cone volcano in Lassen Volcanic ...

  3. Lassen Peak - Wikipedia

    en.wikipedia.org/wiki/Lassen_Peak

    The youngest mafic volcano in the Lassen volcanic center, [53] it is surrounded by unvegetated block lava and has concentric craters at its summit. [52] Cinder Cone is comprised by five basaltic andesite and andesite lava flows, and it also has two cinder cone volcanoes, with two scoria cones, the first of which was mostly destroyed by lava ...

  4. Cinder cone - Wikipedia

    en.wikipedia.org/wiki/Cinder_cone

    Cinder cones are also commonly found on the flanks of shield volcanoes, stratovolcanoes, and calderas. [3] For example, geologists have identified nearly 100 cinder cones on the flanks of Mauna Kea, a shield volcano located on the island of Hawaii. [3] Such cinder cones likely represent the final stages of activity of a mafic volcano. [11]

  5. Mafic - Wikipedia

    en.wikipedia.org/wiki/Mafic

    A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include basalt, diabase and gabbro. Mafic rocks often also contain calcium-rich varieties of plagioclase ...

  6. Level Mountain - Wikipedia

    en.wikipedia.org/wiki/Level_Mountain

    The mafic shield-building stage 14.9 to 6.9 million years ago began with the eruption of thin mafic lava flows over an erosion surface. [5] Successive eruptions sent lava pouring in all directions from central vents, forming a broad, gently sloping volcano of flat, domical shape, with a profile much like that of a warrior's shield.

  7. Gabbro - Wikipedia

    en.wikipedia.org/wiki/Gabbro

    A rock with over 90% mafic mineral content will be classified instead as an ultramafic rock. A gabbroic rock with less than 10% mafic mineral content will be classified as an anorthosite. [8] [13] A more detailed classification is based on the relative percentages of plagioclase, pyroxene, hornblende, and olivine. The end members are: [8] [13]

  8. Belknap Crater - Wikipedia

    en.wikipedia.org/wiki/Belknap_Crater

    Belknap was the last volcano to erupt in the Three Sisters area. [21] Basaltic andesite dominates the eruptive material in the local mafic volcanoes, which range from early Pleistocene to Holocene age. [22] Belknap is one of the larger mafic volcanoes in the Sisters Reach, more than 30 of which run continuously along the segment. [22]

  9. Bimodal volcanism - Wikipedia

    en.wikipedia.org/wiki/Bimodal_volcanism

    Most examples come from areas of active continental rifting such as the Basin and Range Province. Bimodal volcanism has also been described from areas of transtension, [2] the early phases of back-arc basin formation [3] and in the products of both continental and oceanic hotspots (e.g. Yellowstone, Anahim and the Canary Islands). [4] [5] [6]