Showing papers by "Ken J. Woolfe published in 1996"

Deposits of a rapidly eroding meandering river: Terrace cut and fill in the Taupo Volcanic Zone

Abstract: River terraces in a section of the upper Rangitaiki River have formed in the last 1850 years as the river rapidly regrades following a major volcanic eruption (Taupo Tephra Formation). Terrace treads are cut at the migrating outside edge of meander loops and are subsequently filled by scroll and point bar deposits associated with the same loop. Entrenchment rates as high as 5 mm/yr cause the meanders to be permanently abandoned following cutoff. This results in the widespread preservation of fluvial cover sequences up to 6 m thick in an otherwise strongly erosive regime.

Fields in the spectrum of channel style

Abstract: The classification of channel styles has to date proved difficult, with most schemes having been constructed around a series of geomorphological end-members which are inherently unable to describe the continuum of channel morphologies. We present a framework that accommodates all possible channel-interchannel configurations and facilitates the continued use of existing channel classification schemes. By considering the relative rates of channel and interchannel accumulation, a model has been derived with the potential to predict bed geometry and preservation potential for the entire spectrum of aggrading and eroding channels. The model identifies stability fields for all potential configurations of channel and interchannel areas. Significantly, the model predicts that the transition from aggrading to eroding systems need not be accompanied by a change from raised to incised channels.

Mire death in the Bowen to Scott-Denison interval, Collinsville Coal Measures, Queensland

Abstract: Element‐scale mapping of highwall sequences in the Bowen Central Open Cut, Collinsville, has revealed previously undocumented relationships between coal seams and their adjacent sediments. The Bowen mire was overwhelmed by laterally extensive muddy elements (lake/lagoon) as sea‐level rose, forming a flat land surface. In contrast, the Little Bowen, Potts and Scott‐Denison mires were progressively overrun by small‐scale channels which slowly encroached upon them as sediment supply increased. The two upper mires developed by blanketing an irregular surface of up to 8 m of relief. Notwithstanding the presence of mires, siliciclastic flood‐plain sedimentation was either absent or not preserved.