Volcanic plateau up by foundering of the Earth's crust to form the present ocean basin. The Earth features numerous subaerial and submarine volcanic plateaus such as the Columbia River Plateau (subaerial) and the vast Ontong Java Plateau (submarine). Pyroclastic plateaus are produced by massive pyroclastic flows and they are underlain by pyroclastic rocks: agglomerates, tephra, volcanic ashes cemented into tuffs, mafic or felsic. Examples include Shirasu-Daichi which covers almost all of Southern Kyūshū, Japan and the North Island Volcanic Plateau in New Zealand. Volcanic plateau A volcanic plateau is a plateau produced by volcanic activity. There are two main types: lava plateaus
Volcanogenic massive sulfide ore deposit with varying tectonic setting and geological environment during the formation of the VMS. The above groups In the geological past, the majority of VMS deposits were formed in rift environments associated with volcanic rocks. In particular, they formed throughout geological time associated with mid-ocean ridge spreading centres, back-arc spreading centres, and forearc spreading centres. A common theme to all environments of VMS deposits through time is the association with spreading (i.e., an extensional geodynamic regime). The deposits are typically associated with bimodal sequences (sequences with subequal percentages of mafic and felsic rocks - e.g., Noranda or Kuroko), felsic and sediment-rich