Category: australasia

Paul D Taylor The beach near Maunganui on the north coast of Chatham Island. The Chatham Islands are a far-flung outpost of New Zealand (Fig. 1). This isolated archipelago sits in the Pacific Ocean, some 850km east of Christchurch, and lies very close to the International Date Line, making the Chatham Islands one of the first places in the world to see the dawning of each new day. Few New Zealanders have ever visited the Chatham Islands – most know of them only from the country’s national weather forecast. Fig. 1. Map of the Chatham Islands. Inset shows their location relative to the New Zealand mainland. Just over 700 people inhabit the Chathams. The great majority live on the main Chatham Island, with about 30 on the smaller Pitt Island. The islands were first visited by Europeans in 1791, who arrived aboard HMS Chatham, captained by Lieutenant William Robert Broughton. At that time, they were inhabited by a peace-loving people called the Moriori, who had probably colonised them from the New Zealand mainland about 500 years ago. European visitors, including whalers, were later joined by Māori from the North Island of New Zealand, setting in motion a series of tragic events that culminated in the extinction of the native Moriori. The last full-blood Moriori – Tommy Solomon – died in 1933. I’ve had the good fortune to visit the Chatham Islands on three occasions, each time to study and collect Cretaceous and Cenozoic bryozoans under the expert guidance of Hamish … Read More

Dr Susan Parfrey (Australia) You may be familiar with collecting fossils from eroded rock surfaces, a riverbank, a road or rail cutting, a cliff face or a fresh cut surface such as a quarry. But there is another way fossils can be recovered – from boreholes. Boreholes have been drilled in Queensland for many years for exploration and to investigate the regional geology. Since Queensland is a relatively flat part of Australia, outcrops can be hard for geologists to find. Therefore, drilling offers a way of studying sub-surface geology that assists in the understanding of the stratigraphy of the State. Usually, drilling does not produce usable macrofossils. The process of drilling normally involves pushing a mud mixture down the borehole and over the bit, for cooling and lubrication. In this process, larger fossils are forced to the surface in the drilling mud and are broken into small pieces making them impossible to identify. However, microfossils can be recovered, as they are so small they are undamaged by the drilling process and are recovered at the surface to be identified and used in biostratigraphy (to date and correlate rocks). However, in Queensland, drilling was undertaken by the Geological Survey that retrieved lengths of core which provided access to deeply-buried strata and allowed recovery of both micro and macrofossils. Exploration companies also often retrieved short lengths of core at specific levels of interest, which sometimes contain fossils. Before a borehole is drilled, considerable geological mapping of the surface is undertaken. Only then … Read More

Heather Wilson (New Zealand) Fig. 1. The location of Curio Bay. The 180 million year old fossilised forest at New Zealand’s Curio Bay is of international geological significance. When I visited the area recently, the wind was blowing a gale and there were high seas. There is a two-minute walk from the car park to a lookout and then a series of steps down to the beach. When the rocks and fossilised trees are wet, they are slippery, so you need good footwear. This is a protected area. When I visited, there was a representative from the Department of Conservation guarding the beach. There are also video cameras keeping an eye on the fossilised forest, making sure it doesn’t gradually vanish as a result of tourists and rock hounds making off with specimens. Fig. 2. View of Curio Bay. This is one of the most extensive and least disturbed examples of a Jurassic fossil forest in the world. The area within which it is found stretches for about 20km, from Curio Bay, south-west to Slope Point. When the forest was living (during the Middle Jurassic epoch), New Zealand was part of the eastern margin of the ancient super-continent known as Gondwana. North of Curio Bay, most of the country’s future land area was beneath the sea. The fossilised trees occur in green sandstones, alternating with blue shaley clays containing plant impressions. Silica has entirely replaced the woody structure of the trees and rendered them extremely resistant to erosion. Therefore, they … Read More