A Blog About Stone Gathering, Tumbling and Polishing, and Rocks and Landscapes, from New Zealand – With Musical Interludes (john.tumblestone@gmail.com)
I have recently returned from a few weeks in the South Island of New Zealand, travelling by car, collecting stones from places like Charleston, Riverton, Orepuki and Birdlings Flat and visiting interesting landscapes like the limestone caves and arches of the Oparara Basin (north of Karamea), Arthurs Pass, Lakes Pukaki and Tekapo, Curio Bay, Waipapa Point, the Moeraki boulders, and the post-earthquake Kaikoura coast.
One of the first places we stayed at was Karamea in the north Buller region of the West Coast. From there we drove the narrow gravel road north to the Oparara Basin and walked to the Oparara Arch, Moria Gate and other limestone caves and landforms.
Oparara Arch, towering high up, a limestone feature
The cave beneath Oparara Arch
In the Oparara River, just below the Oparara Arch
Moria Gate, another limestone arch/cave
Looking out of the cave onto the river at Moria Gate
Looking upstream at Moria Gate
Moria Gate limestone, in the cave
Inside the “Crazy Paving Cave”, Oparara Basin – the patterns are made by dried mud
A rare protected native spelungula spider on the wall of the “Box Canyon Cave”, Oparara Basin
We saw a lot of wekas in the Buller/West Coast area – a cheeky native flightless bird. This one was in the Oparara Basin carpark.
I collected a small number of limestone stones from the Oparara River – they appear to have fossilised shells in them.
Going south along the West Coast, beyond Westport is the town of Charleston and its small twin bays, Constant Bay and Joyce Bay. Constant Bay was named after the ketch “Constant” whose Captain, Charles Bonner, in the mid 1860s managed to squeeze the boat into into the tiny bay, bringing supplies for the town that had sprung up due to the discovery of gold. The rocks that line the shore of these bays have large veins of quartz with masses of mica in them. At the northern end of Joyce Bay we came across of pocket of stones and rocks from a vein that must have been almost pure mica. We chose one small boulder-sized rock to bring home.
Constant Bay
Veins of mica-rich quartz in rocks at Constant Bay
Another detail of Joyce Bay mica rock
Masses of mica in rock at Joyce Bay
Mica in quartz vein, Constant Bay
Rock brought home from Joyce Bay. It must be at least 95% mica. Large mica piece at bottom centre, other pieces of mica throughout the rock
Detail of Joyce Bay rock made up primarily of mica
There is so much mica in the rocks around Constant and Joyce Bays that the sea sparkles with it.
One hundred kilometres south of Charleston is Kumara, where we undertook a short walk to see Londonderry Rock. This enormous 4000 tonne glacial erratic was dislodged by miners while sluicing for gold in the early 1880s. As noted on the information panel at the start of the walk, local legend has it that when it was dislodged from its position it caused earthquake-like shudders that stopped the clock in the post office!
Information Panel at start of the short walk, near Kumara
4,000 tonnes Londonderry Rock; Petra standing to the right side
Londonderry Rock, towering and massive
Along the track are many large boulders left over from the gold sluicing
Hidden in the bush, large piles of boulder tailings
The clock stopped!
Driving across Arthur’s Pass, we passed Castle Hill, Omarama and Lakes Pukaki and Tekapo.
Castle Hill limestone outcrops
The clay cliffs near Omarama
Omarama’s merino sheep statue
Aoraki/Mt Cook, New Zealand’s highest point
Lake Tekapo
Lake Teakapo, with Aoraki/Mt Cook in the distant clouds
Malham Cove, viewed as we walked back towards Malham village
A man near the edge of the limestone pavement at the top of Malham Cove
Petra walking down towards the top of Malham Cove, towards the limestone pavement
The stunning Malham Cove is a huge curving amphitheatre-shaped cliff formation of carboniferous limestone rock with a vertical face about 80 metres (260 feet) high, with a large area of deeply eroded limestone pavement at the top. On 21 June, on Day Five of an 11 day driving trip in the UK, Petra and I visited Malham Cove while on a four hour walk in the Yorkshire Dales National Park. We started at the National Park Centre in the village of Malham, picking up a leaflet on the Malham Landscape Trail. Embarking on this seven kilometres walk, we followed a path through fields and woods, past stone walls and barns, to a waterfall called Janet’s Foss, to a dramatic canyon called Gordale Scar, and then on to Malham Cove.
Malham Cove was formed by a waterfall carrying meltwater from glaciers at the end of the last Ice Age, more than 12,000 years ago. An extraordinary amount of water was involved, scouring out this large rock ledge and face. This erosion took place more actively at the lip of the fall, hence the curved shape. Today, a small stream named Malham Beck seeps out from the bottom of the massive steep face of the cove.
Approaching the top of Malham Cove
The limestone pavement at the top of Malham Cove
Looking up at people on the skyline, walking on the limestone pavement at the top of Malham Cove
Where the Malham Beck seeps out from the bottom of the Malham Cove cliff face
Petra and Malham Beck
The route we walked took us first to a small hill leading down to the top of the Cove. It was here that we came across the “limestone pavement”, a rock platform that had been exposed by the scouring action of glaciers. Due to the mildly corrosive effects of slightly acidic rain water on the limestone, a process which also leads to the formation of caves and potholes, deep crevasses slowly developed in the rock so that the limestone pavement is actually a “mosaic” of interlocking “clints” and “grykes”. The clints are the flat blocks of limestone separated by the grykes which are deep crevices. As you walk across them, some of the clints move, proving they are sitting loosely. The grykes can be quite deep, maybe as much as a metre to a metre-and-a-half deep. The microclimate of the grykes is more humid and slightly warmer than on the pavement itself, resulting in a different range of vegetation growing in them, such as ferns, wood sorrel, dog’s mercury, and anemones.
Clints and grykes
Petra standing on a clint
Petra looking out towards Malham Village from the top of the Cove
A pigeon looking at Petra taking its picture
Vegetation in the grykes, the result of their micro-climate
Information panel at the top of Malham Cove
The limestone pavement at the top of Malham Cove – spot Petra top centre
Youtube clip of Malham Cove from a drone camera:
Malham’s limestone pavement was used as a location for the 1992 film version of Emily Brontë’s “Wuthering Heights”. It was also featured in “Harry Potter and the Deathly Hallows (Part 1)” as one of the places Hermione and Harry visit.
When Petra and I arrived at the top of Malham Cove, a number of people were intently gazing at a small tree along the face of the side of the Cove. It turned out they were looking at peregrine falcons. Some of these impressive birds of prey have nested at Malham Cove since 1993. At the bottom of the Cove, we came across a viewpoint run by the Royal Society for the Protection of Birds and the Yorkshire Dales National Park Authority. They had set up telescopes for people to look at the peregrines. This year’s chicks had recently fledged.
Peregrine falcon on the side of Malham Cove.
Peregrine falcon viewpoint point at Malham Cove.
Also at the bottom of the Cove, when we walked up to the source of the the stream that runs from its base, we spotted a couple of climbers practicing their moves. Malham Cove is a popular climbing spot and offers significant challenges.
This is an amazing landscape feature, carved out of limestone by ice and water. It is difficult to do it justice.
Youtube clip of the peregrine watch at Malham Cove:
After visiting Earthquakes near Duntroon, we drove about six kilometres further south to an area in the Maerewhenua Valley known as The Elephants. A short walk from a parking bay led to an amazing set of large grey boulders. These limestone rock formations vary from one to ten metres across and lie scattered across a grass paddock on a gently-sloping hillside over an area of about 200 metres. The rocks are rounded from weathering but, despite their names, do not specifically resemble elephant shapes. A set of limestone outcrops borders the area on two of its sides.
As noted on the Information Sign, these large rocks are the weathered remnants of the Otekaike Limestone formation which lies above the Oligocene Kokoamu Greensand (we encountered reference to this sequence at the Information Panel at Earthquakes). Thus the rocks originated at the bottom of the sea some 25 million years ago. When these strata lifted and surfaced, the forces of wind and water did their part in shaping the limestone boulders. The boulders are much larger than a person and walking amongst them makes you feel but a small actor in a large landscape. The following photos convey some sense of this:
The Elephants is a popular site for limestone bouldering (climbing). One climbing website refers to Elephants having “over 300 problems with 80% of them being V3 or below [not too difficult], hence it is a paradise for social climbers looking to improve their skills”.
There is a recent great drone-shot video clip of the Elephants on YouTube:
In 2005, The Elephants were used as the site for the filming of part of “The Lion, the Witch and the Wardrobe”. The scenes of Aslan’s camp were filmed here. When we visited, a deserted film set could be seen up a nearby valley:
Stone polishers become interested in geology and geological formations as therein lie the origins of the stones that have caught our imagination. I have also long felt drawn to limestone landscapes, their outcrops and their caves. Limestone often holds fossils which turn out to be vital to geological dating of strata.
In February 2016, when Petra and I spent a few weeks in the South Island of New Zealand, we visited the Duntroon area in the Waitaki Valley to see the limestone landscapes there. The local community had formed the Vanished World Society in the early 2000s to help raise public awareness about the very interesting geology of the Waitaki district. The Society is active in promoting the science, conservation and appropriate use of local geological resources. The fossils, limestone landscapes and volcanic sequences of the area have been important in the conceptual origins and ongoing development of geological understanding at a national level. Geologists from the University of Otago have developed a positive and ongoing relationship with the landowners in the Waitaki district, primarily as part of a research programme on local fossils.
The Vanished World Trail is a set of more than 20 sign-posted freely-accessible locations spanning coastal localities from Moeraki to Oamaru and extending inland through the Waitaki Valley. After visiting the Vanished World Centre in the village of Duntroon, Petra and I drove 6.5 kilometres down a gravel road to a place known as “Earthquakes”.
As explained in the roadside information panel (see below), the name “Earthquakes” reflected an early-held belief that the limestone cliffs here were a fault escarpment, but it is now thought that a massive landslide created them.
On one side of the road, a locality sign
On the other side of the road, two signs providing information about Earthquakes
We walked up hte lefthand side of this fence
In a 2010 newspaper article, a local historian, Elizabeth McCone, said that visitors needed to take care when wandering through the various crevasse and fault scarps of Earthquakes. “It’s a typical limestone formation and it’s got sinkholes.” Ms McCone reported that there was a commonly held belief among geologists that there was an underground river or waterway originally in the area and the “roof” collapsed, resulting in the unique land formations. “Limestone areas have huge caves and underground rivers. Duntroon has huge caverns underneath it. You can walk under Duntroon for quite a length – almost from the bridge up to the Presbyterian church.”
Petra and I walked up to the Earthquakes cliffs from the roadside and came upon another information panel sited opposite the fossil of an ancient baleen whale.
On the threshold of Earthquakes
On a boulder, looking back downhill, over the roof of the fossil whale towards the Information Panel
The caged fossil whale, embedded in the limestone
We then pressed on, cameras in hand, along the great cliffs, keeping to the narrow pathway worn by previous visitors as it snaked around boulders and crevices. To the right of us ran the long clean line of the towering cliffs. After perhaps just less than a kilometre, they ran out and we turned to look back down the valley before making our return.
The first part of the cliff-face
One of the darker deeper crevices
Looking back down the valley
A smaller set of cliffs on the other side of the valley
