Bryozoan fauna of the Kaipuke siltstone, northwest Nelson: A Miocene homologue of the modern Tasman Bay coralline bryozoan grounds

Abstract

The Kaipuke Siltstone Formation (Westhaven Group) near the Anatori River mouth, northwest Nelson, contains a reasonably well preserved bryozoan fauna of Otaian age. Analysis of this fauna has yielded six species of Cheilostomatida, mostly with an erect-rigid colony form. One new species, Hippoporina miocenica, is described. F-' our of the species appear conspecific with modern hryozoans, including the two species (Celleporaria agglutinans (Hutton) and Hippomenella vellicata (Hutton)) that dominate the modern Tasman Bay bryozoan grounds. From foraminiferal evidence and from what is known of the ecological requirements of the modern bryozoan species it is possible to infer the paleoenvironment of the Kaipuke Siltstone fauna, viz, an area of near-oceanic salinity, water movements able to exceed 0.3 m/s, a seasonal temperature range probably c. 12.5-17°C, and with the possibility of terrigenous sediment accumulation. We conclude that this tauna is an early Miocene homologue of the present-day, ecologically important "Tasman Bay coral" and that this biotope has persisted for at least 20-22 Ma.

Papahu taitapu, gen. et sp. nov., an early Miocene stem odontocete (Cetacea) from New Zealand

“…1). It contains a diverse fossil fauna, most notably bryozoans (Bishop, 1968;Gordon et al, 1994) and sparse macroinvertebrates. Matrix from the skull of OU 22066 yielded poorly preserved foraminiferans, but another sample (M25/f59) collected about 100 m north-northeast along strike contained abundant and better-preserved foraminiferans FIGURE 1.…”

“…1), including the index species Globigerina woodi connecta, indicating an age of upper Waitakian to Otaian (23-19 Ma, Aquitanian to middle Burdigalian). Based on the foraminiferal abundances (Nathan et al, 1986) and the bryozoan fauna (Gordon et al, 1994), the depositional environment of the Kaipuke Siltstone has been interpreted as a mid-shelf setting with a seasonal temperature range of about 12-17…”

Roles of clone–clone interactions in building reef frameworks: principles and examples

“…and if they have positive topographic relief they have been called buildups, mounds, or reef mounds (Bradstock and Gordon 1983;Moisette and Pouyet 1991;Wyse Jackson et al 1991;Gordon et al 1994;Hageman et al 2003). Cuffey (1974Cuffey ( , 1977Cuffey ( , 1985 and Smith (1995) have called extant and fossil bryozoan aggregations reefs or bioherms.…”

“…They are large ''thickets'' or ''self-supporting frameworks,'' 10-30 cm thick, dominated by erect cheilostome zoaria up to 30 cm tall, with hollow branches up to 3 cm in diameter and congeneric ''heads'' up to 1 m in diameter (formed by fusion?). Similarly, Bradstock and Gordon (1983) and Gordon et al (1994) The abundance of fenestellid fragments in the pores of many Late Paleozoic reef frameworks and adjacent levelbottoms does not determine their Baffler Guild membership. Instead, it is their erect or sub-erect live growth habit, weak calcification and lesser skeletal volume than the major builders (sponges, corals) of most Paleozoic reefs.…”

Fossils, sediments, tectonics

“…A growing literature exists on reefs and thickets constructed by bryozoans (e.g., Cuffey et al 1977;Bradstock and Gordon 1983;Gordon et al 1994;Henrich et al 1995;Hageman et al 1998;Batson 2000;Betzler et al 2000;Pedley and Grasso 2002;Cranfield et al 2003;Lukasik and James 2003;Cocito 2004;James et al 2004). These structures range from micro-scale patch reefs (Scholz and Hillmer 1995) to large continuous build-ups, sometimes even dominating carbonate production completely (Hayton et al 1995;Cocito and Ferdeghini 2001).…”