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
Grayson Glades Natural Area Preserve Grayson Glades Natural Area Preserve Grayson Glades Natural Area Preserve is a Natural Area Preserve located in Grayson County, Virginia. Its centerpiece is an extremely rare wetland type known as a "mafic fen", which are situated upon soils rich in magnesium and fed by springs. The site is at the headwaters of a small stream system supporting additional mafic fens. Among the rare species found on the property are tuberous grass-pink ("Calopogon tuberosus"), ten-angled pipewort ("Eriocaulon decangulare" var. "decangulare"), large-leaved grass-of-parnassus ("Parnassia grandifolia"), queen-of-the-prairie ("Filipendula rubra"), sticky false-asphodel ("Triantha glutinosa") and Canada burnet ("Sanguisorba canadensis"). The preserve is owned and