The Holocene evolution of a well nourished gravelly barrier and lagoon complex, Kaitorete “Spit”, Canterbury, New Zealand

An earth systems approach to understanding the tectonic and cultural landscapes of linked marine embayments: Avon‐Heathcote Estuary (Ihutai) and Lake Ellesmere (Waihora), New Zealand

“…Channel avulsion and, by association, variable points of entry to the sea will affect the balance between terrestrial and coastal processes. This is evident by the closing of the AHE-I and corresponding opening of Lake Ellesmere to the sea (Soons et al, 1997) (Fig. 7).…”

“…This scenario implies that, at some point during this time, the Waimakariri River flowed north, which considering the distribution of Waimakariri alluvium is probable (Raeside, 1974). The river also flowed south towards Lake Ellesmere at times during this period (Cox and Mead, 1963;Soons et al, 1997). During this period the estuary probably opened intermittently when the barrier breached.…”

“…There is no record of major earthquakes between deposition of the Older and Younger Waimakariri alluvium, and there is no record of large pulses of alluvium, although Older Waimakariri alluvium and Waikuku sand were probably continually reworked (McFadgen, 1985). Towards the end of this period the Waimakariri River flowed through the 'Heathcote' and 'Avon' River channels towards the AHE-I, and south along the Halswell River channel towards Lake Ellesmere for a short time (Cox and Mead, 1963;Raeside, 1974;Soons et al, 1997), opening Lake Ellesmere to the sea (Fig. 1).…”

“…Rapid deposition of the Selwyn Gravels (part of Ohuan Chronozone) caused the Waimakariri River to flow south again through Lake Ellesmere, opening it to the sea (Soons et al, 1997). At about the same time, a belt of sand dunes formed along Kaitorete Spit, a 22 km long barrier that separates Lake Ellesmere from the sea (Fig.…”

Wave-Dominated Coasts

“…However, coarse clastic barriers also occur on erosional cliffed coasts where the lithology results in a large supply of coarse material or where abundant coarse sediment is supplied from gravel-bed rivers, for example, from the alluvial fans of the Canterbury Plains in New Zealand (Soons et al, 1997). Because of the coarse nature of the sediments, the foreshore and inner shoreface tend to be steep.…”