Landform and vegetation change in the Greaves Creek Basin: An asymmetric hanging valley in the Blue Mountains, New South Wales

Greaves Creek has cut a hanging valley through the entire Triassic sandston e sequence near Blackheath in the western Blue Mountains, New South Wales. Downstream of Beauchamp Falls, it cuts into Permian strata in the Grose Gor ge. The hanging valley has a valley-in-valley structure. The narrow inner v alley is bounded by high cliffs and its floor is cut by a deep narrow slot canyon where stream incision has occurred without valley widening. The cour se of the creek is related to joint directions. Intense jointing, minor fau lting and sapping influence the stability of cliffs but up to 30 m of incis ion has occurred without valley widening in the slot canyon. Topographic as ymmetry expressed as unequal slopes of the valley sides is related to diffe rential insolation, erosion, vegetation cover, bioturbation and fire intens ity. In the western Blue Mountains and elsewhere in the Sydney Basin asymme tric slopes occur in many other valley-ridge systems, particularly those wh ose long axes are oriented between about east-west and north-east-south-wes t. Vegetation structure and floristics within Greaves Creek valley are rela ted to physiography of the valley and to aspect through their effects on fi re, moisture availability, light availability, soil depth and temperature.