Geology of the Brunswick Valley

The Brunswick Valley is part of the Clarence Moreton Basin which is filled with metamorphic and sedimentary rocks up to 500 million years old. 

When Wollumbin (Mt Warning, pictured right) first erupted around 23 million years ago, it poured a basalt forming lava over an area from Lismore in the south to Beechmont, Queensland in the north. Over the next three million years an explosive phase of, among others, acidrhyolites was followed by another lengthy outpouring of basalt forming a dome shaped ‘shield’ volcano.

Since then water draining off the dome in many places has eroded through the volcanic layers to the underlying sedimentary and metamorphic soils and forming river valleys.

The Brunswick river cuts through the south-western edge of the old shield, so the catchment has a variety of soils:

- Alluvial (rudsols, tenosols, dermosols) on the river and creek flats
- Red and yellow podsolic soils (kurusols) on most slopes
- Krasnozem soils (ferrosols) on plateaus and hilly outcrops
- Coastal sands (podosols)

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