Carbonate concretions found within hemipelagic slope sediments of the Urenui Formation, Taranaki Basin (camera case for scale). These concretions display a variety of forms, with the majority having a subvertical and tortuous form. Nelson et al (2004) suggest they may have ultimately originated from ascending methane fluid/gases, and grew entirely within the host slope mudstone sediment. They also invoke a possible causal link between the occurrence of paramoudra and the instigation of slope instability, failure and canyon cutting within the Urenui slope succession.
Nelson, C., Schellenberg, F., King, P., Ricketts, B., Kamp, P., Browne, G. & Campbell, K. 2004. Note on paramoudra-like carbonate concretions in the Urenui Formation, North Taranaki: possible plumbing system for a Late Miocene methane seep field. New Zealand Petroleum Conference Proceedings, 7-10 March 2004 |
Small-scale sand remobilisation within a hemipelagite dominated slope sequence, Taranaki Basin (photograph approximately 15cm wide). Thin injections of coarse-sand can clearly be seen ‘bypassing’ the finer grained layer in the centre of the photograph and creating a continuous fluid pathway. Underlying sediments showed evidence of localised slumping and bed disturbances thought to be responsible for the sand remobilisation. |
Thinly bedded silt/clay sequence within the Ordovician Yr Allt Formation, West Wales. What are the implications of thin beds for migration, trapping and leakage? |
