#alumcliffs - Twitter Hashtag

11 months ago

🟥 ⛏️ The colored sand cliffs at Alum Cliffs (also known as Alum Bay) stand along the coast near Gardners Bay in southern Tasmania. ❤️ 🔁 #AlumCliffs #TasmaniaColouredCliffs 🎞 @Southernersontour ▶️ They consist of Permian siltstone and sandstone about 270 million years old. Vivid horizontal and vertical bands of orange, red, yellow, white, cream, and occasional purple appear across the near-vertical face, which rises to 60 metres high. ▶️ These colors formed through prolonged chemical weathering. ▪️ Groundwater carrying weak organic acids moved through cracks and pores, dissolving iron and manganese minerals in some zones while redepositing them as oxides in others. ▪️ Oxidized iron produces the bright oranges and reds (hematite and goethite), leached areas leave pure white quartz-rich layers, and manganese oxides create rare purple streaks. Coastal waves continually erode the base, keeping the cliff face steep and the colours freshly exposed.