Access

Cave Stream is 3km from Castle Hill Village towards Arthurs Pass.

Track

A loop over Broken River and above the cave is furnished with interpretation panels on the geology and Maori travellers.

Two short tracks lead from the reserve carpark to the cave entrances. The track to the upstream entrance goes north, through a diverse karst (limestone) landscape of solution holes, rillenkarren (water-grooved rocks) and sculptured rock formations.

The other track leads to the edge of a terrace overlooking the outflow entrance of the cave. It drops down the face of the terrace to the junction of Cave Stream and Broken River.

Geology

The rock itself was formed around 30 million years ago from successive layers of marine organisms, mud and sand, which were compressed, heated and then uplifted at the same time as the Craigeburn and Torlesse Ranges. Once surfaced, the weathering agents of wind, water and frost have sculpted the rounded forms of the karst landscape.

Polynesian History

The area around Cave Stream was a stopping off place on the journeys of Maori travellers on their search for greenstone or pounamu. Arthurs Pass was a known crossing of Ka Tiritiri O Te Moana.

In geologist’s speak, greenstone means ‘the fine grained rocks consisting essentially of either tremolitic amphiboles or serpentines’. It occurs is many different forms, including nephrite, semi-nephrite and talc schists. All forms come under the banner jade.

Other forms of pounamu include the harder nephrite, which found use in adzes and axe heads. Apart from obsidian, sourced mainly in the North Island, nephrite was the only stone that could be fashioned into a sharp point, durable enough to withstand felling trees or excavating waka.

The revered toughness stems from its formation, deep within the Earth’s crust. New Zealand/Aotearoa lies on a gash in the Earth’s crust known as the Alpine Fault. Along this line of weakness the Indo-Australian plate crashes with the Pacific Plate in a battle of tectonic proportions. The pressures are immense. When minerals such as peridotite, pyroxenite, hornblendite and serpentine, locked up in igneous rocks, are subjected to intense heat and pressure, the rocks melt. As the crystals reform, they realign, linking in a tightly woven tapestry. The weave is known to geologists as felting. When this process occurs completely, it forms true nephrite.

The unique geological recipe and method from which greenstone can be concocted is rare. Sources of the stone are scarce, the rarity enhancing its value and desirability as a commodity. Coupled with the fact most locations of greenstone happened to occur in isolated inaccessible areas, then we can begin to understand how precious the stone was.

The Arahura River was reckoned to be the richest source, with other main fields occurring around the Taramakau River, the New River, the Hokitika River, the Dart River and the Routeburn. In each location the raw ingredients differed slightly, the nuances of the recipe changed, as did the type of oven. The stones were prized for their array of qualities, some Arahura and Wakatipu varieties known as inanga, relating to the similar colouring of whitebait.

Pounamu’s rarity also made it a very tradable commodity, especially for tribes who knew where to source it. In raw form, it was moved throughout Aotearoa, over Cook Strait and throughout the North Island. After its long travels through the arterial river systems, it may finally have found exchange for coastal products such as dried fish, seaweed or sea birds. Some pounamu was even carried to the Polynesian homelands.

In today’s world of roads, cars, manicured tramping tracks, huts, Gore-Tex and freeze-dried fodder, we can blissfully overlook the physical hardships Maori would have faced on their journeys to source the sacred pounamu. The entire trip was only undertaken when the correct spiritual signs were aligned and those tohunga in possession of the appropriate knowledge had received guidance that the timing was appropriate.

The Maori pounamu gatherer would then have to undertake a journey of significant danger. The travels to remote sources were often a considerable distance from settlements and, in a culture without the written word or maps, the journeys were attempted with mental maps and song, their GPS and topographical maps of today. Kura Tawhiti was one such place the reverence associated with the stone was observed.

At the source, those entrusted with the task, had to know of the pounamu’s peculiarities. In raw state the stone looks completely different to the polished form of a finished article. They had to see beneath the oxidised rind or rutted surface to imagine the final object. Stone transported down the rivers and onto the beaches had received a natural cut and polish, and was best found after storms or on the outgoing tide. River beds were best scoured after rain, when the pounamu would shine, beacon-like from the jumble of surrounding river stones. Submerged quarry, glinting beneath the ripples of a shallow beach, often caught the eye.

Now came the hard bit - returning with the goods. The migration routes plied by the pounamu hunters are known as the ‘greenstone trails’. We should take a step back however and consider briefly the nuts and bolts of the journeys these early explorers undertook. Imagine being abandoned on a west coast fiord during a downpour. To physically survive, you would need shelter, food and warmth. How would you make fire, catch fish, trap eels or snare birds? Let alone find a navigable route through uncharted wilderness. When we understand how useless we are as Westerners, ignorant of even the most basic survival skills, we can then begin to realise how closely linked Maori must have been with the land. In our society, this passing of generational knowledge and nurturing of spiritual ties with the land is now lost.

In his book The Greenstone Trails, Barry Brailsford says “The Maori trails that traversed Aotearoa were the arteries of economic and social relationships. The language is studded with references to huarahi, or ara – the trails – and the folklore of travel.”

Journeys were undertaken in teams, led by an experienced traveller, who marked the route for future parties. Protruding twigs and branchlets were snapped, a process known as kowata or whati, in a form of route marking known as ara pawhati. Subsequent parties, by curtailing the new growth, could define a route for single file lines. Swamp travel was eased by raising the track using manuka fascines. Chasms were bridged with pole girders and bridge construction sourced vines as the suspension cables. Vertical faces were structured with vine and rope ladders and wooden pegs (ara tiatia) were the olden day hex or cam anchors. Other signposts were more subtle. Early observers such as William Colenso, noted where trials led over moss, those wearing bare feet could sense it’s reluctance to return to the former shape, despite negligible difference in the appearance. What bushcraft!

To cross the numerous rivers, mokihi or flax stalk rafts were used as floats. A tuwhana, or breast pole held horizontally also steadied parties in the turbid currents. Forest clearings (traumata) or wide river flats (okiokinga) were preferred resting places, sited as today’s backcountry huts are. Most routes followed river valleys, as ridges were often too high for safe travel.

The Maori Gore-Tex jacket was a poncho-like cloak, layered with other garments for alpine travel. Tramping boots were worn in the harsher conditions, sandals known as paraerae woven from flax, ti or toi. These were stuffed with tussock (patiti) as the sole liner. A type of woven leg shield (taupa) formed a gaiter. The topographical map, compass and GPS unit were all hardwired to the travellers brain. Mental maps of complicated watersheds, river systems, coasts, resting places, place names and the minutiae of the trails were all committed to memory or passed on through song.