Swansea Heads (Reid's Mistake)3D Model
The rock platform at Swansea Heads is comprised of the middle section of the Boolaroo Formation of the Newcastle Coal Measures. The layers are dipping at ~12° to the west. The outermost part of the platform exposes a fluvial sandstone with cross-bedding, overlain by a thin shale layer which is a floodplain deposit. Above this is the Lower Pilot Seam (~1 metre). The coal seam was deposited as peat in a swamp. Life in the swamp was terminated by a series of volcanic ash eruptions which buried the forest. Over 100 fossil logs and tree stumps have been identified in the ash layer - their orientation can be used to estimate the direction of the blast.
After volcanism waned, the swamp re-established and is represented by the Upper Pilot Seam. A thin layer of siliceous ash below this seam has many spectacularly preserved Glossopteris leaves. Finally, the sequence is overlain by the Belmont Conglomerate which was deposited in an alluvial fan setting. Model courtesy of Ausgeol.org
Comments