Wairere Boulders is a privately-owned nature reserve and tourist attraction at Horeke in the south Hokianga region of Northland, New Zealand. The property contains geologically rare rock formations. Visitors to the property can walk the various boulder and river trails, climb the boulders (Bouldering), kayak the river and estuary, and stay at the campsite.
Wairere Boulders was initially developed as a tourist attraction by Felix and Rita Schaad, a couple originally from Switzerland who owned the property from the 1980s. They opened the site for visitors in 2000, after 4 years work developing tracks, bridges and lookouts. The property was sold in 2017 and again in 2023. [1]
The 140 hectares (350 acres) property was purchased by Mark & Leonie Norton in 2023. They have added hot showers, a community barn, and now also cater for Bouldering. The property includes farmland, and the owners raise highland cattle and sheep. [2] [3] [4]
The unique attraction at the property is the large and unusual fluted basalt rock formations. [4]
There are several walks ranging from 40 minutes to 3 hours, taking visitors under, over and around the boulders. The gigantic rocks are surrounded by subtropical rainforest, where much of the flora is labelled. Added interest for families is provided with rock animals, fairy houses and a swimming hole.
Kayaking is available on the boulder estuary / river. Due to the tidal nature of the boulder river, kayaking is tide dependent. It is possible to kayak down through mangroves and out to the Hokianga Harbour.
Bouldering is supported by a number of local groups who have mapped and graded a large number of the hundreds of boulders on the property. Many boulders are close to the carpark and camp, making access very easy. Boulder mats and chalk a available on site.
The Wairere boulders have moved down the hillsides from an eroding Pliocene basalt lava flow of the Kerikeri volcanic group [5] formerly known as Horeke basalts. Erosion of the clay under the basalt plateau (cap) started to create a valley; the edges of the cap broke off and blocks moved towards the bottom of the valley, where they accumulated. They now fill a portion of the valley which is about 1.4 km long and up to 350 m wide.
Many of the boulders have deep solution basins and fluting formed on their surfaces as they very slowly slid down the valley sides - a particularly good example of the relatively rare phenomenon of karst formation on basalt (sometimes known as proto-karst). [6] This phenomenon was documented by geologists as early as the 1920s-1940s in Hawaii [7] [8] and New Zealand. [9] Usually karst landforms are formed by solution of calcareous rocks (e.g. limestone and marble) by mildly acidic percolating water. At Wairere, and elsewhere, basalt has been dissolved, probably over a much longer interval of time, by the production of weakly acidic humic acid in the leaf litter that collects around the roots of plants that grow on the top of the boulders, usually beneath a forest canopy. [10] On the top of the boulders this humic acid has etched out solution basins 20–50 cm across and of similar depth. Humic acid seeping down the sides of the boulders has, over thousands of years, dissolved deep, near-vertical flutes out of the hard basalt. In some places the fluting is no longer vertical as the boulders have rolled over or tilted since it was formed.
Basalt karst occurs in a number of places in northern New Zealand with some of the best examples at Wairere Boulders, [11] but also at Stoney Batter, Waiheke Island; Ti Point, Leigh; [12] Lake Manuwai, Kerikeri; and Stoney Knowe, Helena Bay. Excellent examples of karst features developed on basalt boulders can be seen on Norfolk Island, in the Tasman Sea.
Karst is a topography formed from the dissolution of soluble carbonate rocks such as limestone and dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. There is some evidence that karst may occur in more weathering-resistant rocks such as quartzite given the right conditions.
In geology, a boulder is a rock fragment with size greater than 25.6 cm (10.1 in) in diameter. Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive. In common usage, a boulder is too large for a person to move. Smaller boulders are usually just called rocks or stones.
The Hokianga is an area surrounding the Hokianga Harbour, also known as the Hokianga River, a long estuarine drowned valley on the west coast in the north of the North Island of New Zealand.
The Auckland volcanic field is an area of monogenetic volcanoes covered by much of the metropolitan area of Auckland, New Zealand's largest city, located in the North Island. The approximately 53 volcanoes in the field have produced a diverse array of maars, tuff rings, scoria cones, and lava flows. With the exception of Rangitoto, no volcano has erupted more than once, but the other eruptions lasted for various periods ranging from a few weeks to several years. Rangitoto erupted several times and recently twice; in an eruption that occurred about 600 years ago, followed by a second eruption approximately 50 years later. The field is fuelled entirely by basaltic magma, unlike the explosive subduction-driven volcanism in the central North Island, such as at Mount Ruapehu and Lake Taupō.
The Horeke basalts is a disused formation that contained Miocene-Pliocene basalt lava flows that covered a large area in central Northland Region of New Zealand, and in places forms a high plateau around Okaihau.
The Moeraki Boulders are unusually large spherical boulders lying along a stretch of Koekohe Beach on the wave-cut Otago coast of New Zealand between Moeraki and Hampden. They occur scattered either as isolated or clusters of boulders within a stretch of beach where they have been protected in a scientific reserve. These boulders are grey-coloured septarian concretions, which have been exhumed from the mudstone and bedrock enclosing them and concentrated on the beach by coastal erosion. Especially in recent years, the boulders have been a popular tourist attraction.
The geology of Ireland consists of the study of the rock formations on the island of Ireland. It includes rocks from every age from Proterozoic to Holocene and a large variety of different rock types is represented. The basalt columns of the Giant's Causeway together with geologically significant sections of the adjacent coast have been declared a World Heritage Site. The geological detail follows the major events in Ireland's past based on the geological timescale.
New Jersey is a very geologically and geographically diverse region in the United States' Middle Atlantic region, offering variety from the Appalachian Mountains and the Highlands in the state's northwest, to the Atlantic Coastal Plain region that encompasses both the Pine Barrens and the Jersey Shore. The state's geological features have impacted the course of settlement, development, commerce and industry over the past four centuries.
Horeke is a settlement in the upper reaches of the Hokianga Harbour in Northland, New Zealand. Kohukohu is just across the harbour. The Horeke basalts are located near the town, and can be viewed on an easy stroll through the Wairere Boulders, a commercial park.
Glacial flutes, also known as glacial fluting, are low, narrow, elongate, straight, parallel ridges that range between several centimeters to a few meters both in width and height. This glacial landform generally consist of glacial till, but sometimes either sand or silt and clay. They form subglacially and are orientated parallel to the direction of glacier flow. They occur in parallel sets of ridges known as swarms. Because of their narrow width and low height, they are often hard to identify during ground or bottom surveys. As a result, they have to be mapped by high-resolution satellite data or LiDAR techniques on land and by high-resolution side-scan sonar at sea.
The Waikato and King Country regions of New Zealand are built upon a basement of greywacke rocks, which form many of the hills. Much of the land to the west of the Waikato River and in the King Country to the south has been covered by limestone and sandstone, forming bluffs and a karst landscape. The volcanic cones of Karioi and Pirongia dominate the landscape near Raglan and Kawhia Harbours. To the east, the land has been covered with ignimbrite deposits from the Taupō Volcanic Zone. Large amounts of pumice from the Taupō Volcanic Zone have been deposited in the Waikato Basin and Hauraki Plains.
A solutional cave, solution cave, or karst cave is a cave usually formed in a soluble rock like limestone (Calcium carbonate CaCO3). It is the most frequently occurring type of cave. It can also form in other rocks, including chalk, dolomite, marble, salt beds, and gypsum.
New Zealand's Northland region is built upon a basement consisting mainly of greywacke rocks, which are exposed on the eastern side of the peninsula. In-place Eocene coal measures crop out at Kamo, near Whangārei, and Oligocene limestone crops out at Hikurangi, near Whangārei.
Matukutūreia / McLaughlins Mountain is one of the volcanic cones in the Auckland volcanic field. It has a peak 73 metres above sea level, and was the site of a pā. The scoria cone was originally crescent-shaped and featured Māori terraces and kumara pits, before extensive quarrying reduced it to a pyramid-shaped mound big enough to support the summit water tank for Papatoetoe. A small part of the summit and the eastern side of the cone were left unquarried, plus a large area of lava flows to the south of the cone remains intact. These remaining parts have recently been transferred to Department of Conservation Management, primarily because of the high heritage values of the Matukuturua Stonefields gardens.
The recently active basaltic Kaikohe-Bay of Islands volcanic field in the Northland region of New Zealand is associated geographically with an older region of extinct volcanism to its north the Wairakau Volcanic Centre, meaning eruptions in this region have occurred over the last 20 million years. All the cones older than 2 million years have eroded away, leaving plateaus from Ōkaihau to Kerikeri and north to Whangaroa from the old andesite/dacite stratovolcanoes of the Wairakau Volcanic Centre and the ten million year old or more recent volcanoes in field towards the south. In the southern part of the field, around 12 small basaltic scoria cones, and a rhyolite dome erupted in the last 500,000 years around Kaikohe. The field is considered dormant, rather than extinct.
Pouerua is a 270 m (890 ft) high basaltic scoria cone, in the Kaikohe-Bay of Islands volcanic field in New Zealand. It is in the locality of Pakaraka and was the site of a pā that was studied during a major archeological project in the 1980s. Pouerua is registered with the Historic Places Trust as a traditional site.
Grafton Volcano is a buried volcano in New Zealand's Auckland volcanic field that underlies much of the Auckland suburb of Grafton. First recognised in 2010, it includes the Outhwaite Park scoria cone that was first mapped by Hochstetter (1864) and inferred by later geologists to be a late phase vent of adjacent Pukekawa Volcano. Borehole drilling and building excavations in the Grafton-Auckland Domain area during the 1990s and 2000s provided new subsurface geological information that allowed geologists to recognise the buried Grafton Volcano.
Bruce William Hayward is a New Zealand geologist, marine ecologist, and author. He is known as a leading expert on living and fossil foraminifera.