Search results for "pyroclastic"

  • Pyroclastic processes and materials

    Pyroclastic means 'fire broken' and is the term for rocks formed from fragments produced by volcanic explosions.

  • Volcanic landforms

    Each type of volcanic massif (structure) contains lavas, pyroclastic rocks and intrusions, but these differ in proportions and compositions.

  • Volcanic rocks

    Volcanic rocks are divided into three main types: basaltic, volcaniclastic and pyroclastic.

  • Igneous rock types

    Igneous rocks can be divided up into four groups, based on how they were formed and what they are made of.

  • Long Island, Papua New Guinea: aspects of landforms and tephrostratigraphy


  • Possible origins and ages for sapphire and diamond from the central Queensland gem fields


  • Lavas

    One of the products of volcanic eruptions is lava. Lavas vary widely in composition depending upon their original source magma, which is most strongly influenced by the plate tectonic setting of a particular volcanic structure.

  • Classification of igneous rocks

    Igneous rocks are formed when magma cools and solidifies. They are classified by using grain size, silica content, and/or silica saturation. Other methods of classification include the International Union of Geological Sciences (IUGS) scheme and the Total Alkalis vs Silica scheme.

  • Pumice


  • Structure of volcanoes

    Although volcanoes are commonly seen as being destructive (when they destroy buildings, infrastructure and farmers' fields), they are also constructive. They add more land to the surface of the Earth, help us understand about volcanic processes and what makes up the deep Earth (by transporting fragments to the surface) and, when weathered, provide us with a nutrient-rich soil for agriculture.

  • Magma

    Magma is hot molten mobile rock. Igneous rocks form when magma cools and solidifies. Magmas come out of active volcanoes as lavas. The most abundant magma is a melt of silicate composition and this can carry suspended crystals and gases which bubble out in air.

  • Carboys and cinder cones

    Filtering seawater and sediment to identify marine biodiversity in the Northern Mariana Islands

  • Geological ore deposits

    Geological ore deposits are of many different types and occur in all geological environments.