Nature, culture and history

Columnar basalt, Mount Scoria Conservation Park.

Photo credit: Queensland Government

Natural environment

Mount Scoria is an obvious and impressive landmark, although not large compared with most mountains. It rises 150m above the surrounding plain and has a base less than 2km in circumference. It features unusual and impressive basalt columns inclined at various angles.

Mount Scoria was the site of an active volcano about 20 to 26 million years ago. The mountain was formed by a basalt lava that intruded into the vent of a small volcano, whose cone has since eroded away. The lava formed a plug within the volcano, which—as it cooled—formed distinct columns or pillars with five to eight sides, called columnar basalt.

The six-sided columns formed from very regular cooling and contraction, while less-even contraction produced five, seven and eight-sided columns.

The columns formed perpendicular to the cooling surfaces, which, at Mount Scoria, were probably the steep sides of the plug. The angles you see today presumably relate to the direction of cooling in the once hot lava mass.

The columns are best viewed from the walking track. Please do not strike them as this can cause significant damage.

The name Mount Scoria is derived from scoriaceous basalt, or scoria, which is slightly misleading as very little scoria is found here. Scoria is a light-weight basalt that has abundant round gas-bubble cavities, whereas the basalt on the mountain is mostly a denser rock, with just a few gas bubbles, known as vesicular basalt.

Scoria forms when gaseous blobs of lava are ejected from a volcano, typically forming a scoria cone around the vent. When solidified, the scoria has lots of small holes that are the result of the gas bubbles escaping from the molten lava during its rapid cooling and solidification. The small amount of scoria in the park suggests that a scoria cone that might have been here has since eroded away, and that the mountain’s formation was a slow-cooling lava plug rather than a fiery explosive eruption.

For an in-depth look at geology in national parks in this region, obtain a copy of Rocks and Landscapes of the National Parks of Central Queensland by Warwick Willmott (Geological Society of Australia, Qld Div).

Brigalow communities provide habitat for many threatened species.

Photo credit: © Ross Naumann, QPWS volunteer

Plants

The northern and eastern sections of the park contain woodland dominated by poplar box (Eucalyptus populnea), silver-leaved ironbark (Eucalyptus melanophloia), some Moreton Bay ash (Corymbia tessellaris) and forest red gum (Eucalyptus tereticornis).

Small areas of brigalow Acacia harpophylla grow on the mountain’s lower slopes. This endangered ecosystem grows in association with Queensland ebony Lysiphyllum hookeri and currant bush Carissa ovata.

The vegetation on the eastern and southern slopes of Mount Scoria is a good example of an open type of semi-evergreen vine thicket. The open structure of the thicket is unusual in Central East Queensland and most closely resembles deciduous vine thickets occurring further north.

Queensland bottle trees (Brachychiton rupestris), broad-leaved bottle trees (Brachychiton australis) and native bauhinias (Lysiphyllum hookeri) are prominent among the 72 plant species recorded here.

Culture and history

Mount Scoria Conservation Park is part of the Gangulu Nation People's traditional country. Gangulu People call the mountain Dangama Mungar—Talking Mountain. The Gangulu Nation People consider Dangama Mungar—along with a number of other mountains in the area and Lake Victoria north-west of Biloela—to be culturally significant. Signs along the short walking trail tell cultural stories of the Gangulu Nation People.