Expedition Name (& Club): There and Back Again (Imperial College Caving Club)

Destination country: New Zealand
Region: Mount Owen

Lat: -41.5190 Long: 172.5613 Elevation: 1161 m
MEF funding: none

Leader: Mr Rhys Tyers

Brief Expedition objectives:

List a short summary of the main Expedition objectives.

Discovery and surveying of new caves on the north aspect of Mt Owen, one of the Marble Hills in the Kahurangi National Park. Dye tracing between Bulmer Cavern, the longest cave system in New Zealand reveals a link to the Blue Creek resurgence 8km to the north. We intend to surface bash for new caves which may lead into the master system below, or to horizontal fossil passage above the master system.

How can the GPF support your Expedition?:

Please explain the aspects of the trip which make it eligible for Ghar Parau funding.

We have obtained funding of £1050 per person from the Exploration Board of Imperial College London. The Board requires us to provide a further £500 per person of funding from personal contributions or other grants. We are looking for additional funding to meet this requirement, and lower the £500 barrier to entry for young cavers. Our expedition is ideal for the GPF, as we have a high potential to discover new caves, we will gain valuable experience with cave exploration, we have excellent connections with local groups and we will benefit the sport as a whole by training the younger generation of cavers with the skills they need to lead expeditions in the future.

Imperial College has had significant success with the Slovenia expedition for the last 20 years, which is a mature and well run expedition. The proposed expedition will enable young cavers to experience the first steps of setting up a successful expedition in almost virgin territory.

Detailed description of objectives:

Give a more detailed account of the purpose of the trip, including any particular known caves you intend to visit, specific areas where you will explore for new cave, and scientific experiments you will attempt.

New Zealand is home to the deepest caves in the southern hemisphere. In the last decade, Bulmer Cavern, on the south side of Mt Owen, has been surveyed as the longest cave system in New Zealand. Dye tracing indicates that there is an unexplored connection passingg under the north slope of Mt Owen, as the dye has been traced to the Blue Creek resurgence some 8km away. Some caves have been found on the Mt Owen massif in the period 1960-2000, but the exploration has been sporadic, and used older rope techniques. A thorough, focused expedition using SRT and modern equipment stands an excellent chance of discovering new caves in this practically unexplored region.

We will set up a base camp at around 1100 m, on the broad, unforested plateau that makes up the north aspect of Mt Owen. The terrain is broken and karstic, with plentiful streams for drinking water. The base camp will have solar panels for power, gas powered stoves for cooking and a tarpaulin to create a sheltered cooking space based around an overhanging rock identified as a suitable place by our local contact Kieran MacKay. Our equipment will be flown in by helicopter - our team will hike in along a well trodden track from the car park six hours to the north.

We will spend the first few days exploring the surface in groups of three, without caving equipment, geolocating potential leads using GPS, and marking them on topo-maps for consideration. We will then push any potential leads in teams of three, bolting using drills where necessary. Any lead longer than 100m will be surveyed to BCA grade 4-5 with compass, inclinometer and tape measure, and producing a centreline using survex. One group of three will remain on the surface at all times to provide back up, search for new leads and communicate with the outside world via satellite phone.

We hope to find vertical shafts leading to significant horizontal passage, either in the master system below the mountain, or fossil passage above the master system. We will preferentially push leads that contribute to this objective.

Previous work in this area:

Give details of any previous work in this area by your own and other teams. Include references to reports and articles published on the area, and the names of any local cavers or academics with whom you have discussed the Expedition.

The first cavern of Mount Owen to be explored in a systematic fashion is Bulmer cavern. In 1986 it reached its deepest point (-755 m). It is still actively explored and is the longest cave system in the country. Bohemia cave, the fifth deepest in New Zealand (-713 m) was pushed to its maximum depth in 1994. Other smaller caves such as Curtis Ghyll (-291 m) or Giant’s Staircase (-259 m) were quickly descended and explored in the 1960’s. In order to prevent exploration of caves by inexperienced hikers, the cave entrances do not appear on classic explorer maps. Our access to the cave entrance locations is through the Nelson Speleological Group. Exploration in New Zealand is generally organised around the availability of the cavers and expeditions are planned in advance and shared globally with the community. The latest development in the exploration of Mount Owen are related to the dye tracing experiments which show a connection between the far reaches of Bulmer cavern to the Blue creek resurgence.

The geology around Mount Owen is complex and still subject of active research. The Nelson district is comprised of rocks from all geological ages. The Alpine fault, a major tectonic plate boundary between the Indo Australian and Pacific plates strikes south westerly through the district and is causing the uplift of the Southern Alps. The Arthur Marble, of which Mount Owen is Ordovician in period (485-443 Ma) and is a heavily folded and faulted metamorphic rock derived from a pure limestone. It appears to have undergone an increasing metamorphic grade from low altitudes toward the heights. The limestone is believed to have undergone regional ( high grade ) metamorphism in the core of the range to which Mount Owen appertains. It is characterised by a series of folds, which have then undergone extensive brittle failure, hence the presence of major thrust faults, and fault propagation folds associated with them. It has since been uplifted and eroded by humid westerly winds of this particular latitude. The speleogenesis of the marble caves, of which Bulmer cavern is a prime example is mostly due to carbonic dissolution. Because of the high rates of uplift measured in this area of New Zealand, the karstification process is already well at work, leaving the potential for depth as well as horizontal development at depth. This potential is demonstrated by Mount Owen and Mount Arthur boasting both the three deepest and three longest caves in the country.

Structure, fabric, metamorphism of Arthur Marble in Pikikiruna Range, Nelson, New Zealand (David Shelley et al., 2010)