The World's Longest Sea Caves Part I

In celebration of my 100th blog post, I could not help but indulge the few regular visitors with a teaser of a project I have been working on for quite a while now in relative secret. What started as desperation to find local caves has turned into an obsession of sorts, as each subsequent visit has revealed an ever-extensive network of sea caves unlike the world has known. In terms of beauty and joy to explore, these sea caves are unrivaled in my opinion. Decorated halls, echo chambers, extensive mazes, long kayak-able passages, impressive squeezes, and abundant sea life, all guarded by unassuming entrances and formidable seas. Before I knew it I found myself exploring several of the world's longest sea caves, a list soon to be re-written. You heard it here first :)

Some of the caves are on sandy beaches or have good cliff access and have thus received repeated visits over the years. These caves have graffiti carved into their walls, some going as far back as 1872. The vast majority of the caves however are extremely well-protected by land access via high unbroken cliffs and frequent strong swells and surging waves by sea. Although some locals know of the caves, only a handful have entered and no one has realized the true extent of the caves until now. These are not places to go without the right knowledge and expertise, and as I have witnessed, even good conditions can change fast. Undoubtedly, we were the first to enter some of them, an exciting prospect to a caver who knows few greater thrills than exploring virgin passage.

Access is so finicky that the first several times we made attempts on accessing the caves by kayak we were turned back by waves breaking onto the caves and could not even get close. These trips at least helped to hone some confidence and paddling skills on open seas. Since then I have a much better appreciation of the specific conditions necessary to enter and have had a much higher success rate. My life at the moment is now ruled by tides and swells as the narrow window of perfect conditions happens but once every two to three weeks. If I need to ditch school mid-week, so be it; I can always work through the weekend.









These sea caves are unusual for their length, concentration and copious calcite formations. Many factors including rock type, fractures, coastal uplift and swell strength have been more or less perfect for the caves' creation. That said they are still anomalous and many mysteries remain. The caves can be extremely moody depending on swell and lighting conditions. At times they can suck light into their foggy darkness with tumultuous noises echoing around surging chambers causing much intimidation, at other times light can project far into calm passages, illuminating much.

These caves have been a great joy to explore. On three separate occasions I found a cave I was convinced was the longest sea cave in the world, only to return another day to find one even longer. I explored the undoubtedly longest sea cave completely alone one day, making for some of the most enjoyable exploration and one of the best days of my life. I went into a small unpromising entrance, that after swimming and wading through a maze of passages, connected to an extensive cave found on a previous day. Going further I came to a beautifully decorated collapse chamber. The most amazing thing about this cave is three times it seemed to end convincingly, and three times careful looking revealed a passage that just barely continued on to the rest of the cave. In this manner I passed two impressive squeezes to where the cave finally ended at a spectacular amphitheater-like, side-lit subterranean beach with stalactites overhead.









While most has now been explored, several areas remain to be checked and I have only just begun surveying and mapping these caves. Surveying these sea caves poses new challenges I have not had to deal with in cave surveying before. Keeping the precious instruments and all-important sketch dry can be quite a chore, especially when no part of you is dry. Being at the mercy of the tides usually leaves a narrow window in which to survey as low tide can pass quickly and the passages fill with water. Surveying by kayak was a new and novel approach for me and surveying while waist deep in cold water gets rather cold rather fast, even when wearing a wetsuit.

Several people have been involved in this project and will be dutifully acknowledged once the project wraps up. We still have much to explore and survey. Once I release the finished maps, New Zealand will not only host the world's most voluminous sea cave (Riko Riko Cave in the Poor Knights), but will also lay claim to the world's longest sea cave. To be continued...

***Thanks to all my friends and family who read and [hopefully] enjoy this blog. Any suggestions for improvement would be kindly appreciated.***





Palmerston Cave July 3

A short walk across paddocks, up a hill, along a farm track and into a valley led to Palmerston Cave, Otago's only known marble cave. The valley is mostly grassy hillsides but the marble bluffs are typically guarded by remnants of broadleaf bush with impressive bushlawyer in places. The rather impressive entrance is perfectly hidden by a broadleaf tree. A scree slope leads down into the well-lit main chamber floored with breakdown boulders. Bones found in this cave include many extinct or rare birds including kiwi, kereru, kakapo, laughing owl and several species of moa. The side passage to the north requires a bit of crawling to reach a small room. The side passage to the south at the back of the cave leads to graffiti (dating to 1929) and a moderately amusing 3.5m climb up old flowstone where another short but greasy climb led to more graffiti and a convincing end.

Walking a short distance down the dry streambed from Palmerston Cave, one is abruptly bombarded by the sound of water. Two very sizable springs are encountered filtering between large marble boulders. Just below this point, the formerly-dry creekbed is now restored to its correct flow. Just up the hillside from the springs, a downward sloping leaf-litter pancake entrance with a bedrock roof was rediscovered and entered. This second cave is about 40m long with a few small side passages. The passage morphology and scallops on the walls suggest this was formerly a stream passage emerging from the hillside. A vertical squeeze near the entrance leads to a small room where the stream rises up through breakdown into a calm pool which probably drains out to the springs. Almost got my feet wet here!

Palmerston Cave seems to be a former submergence of the creek with the small resurgence cave being a part of the same system. The present day creek must sink into marble underlying its bed, (possibly several kilometers upstream of Palmerston Cave) flow directly underneath the cave and emerge more or less directly underneath its former resurgence. Sadly, the current karst system may be too youthful to enter. We continued walking down the creek to have a look at the marble downstream. While marble was abundant and we saw a sizable karst spring with a concrete weir marked “Blue Bell 1910,” no entrances were found. While karst features are few and much of the marble is visible, all it takes is one bush or tree to hide a cave.

Photo by Lara

Karitane-Warrington Coast July 1

What can I say, I had been working hard and was in desperate need to ditch school. I decided to traverse the coastline from Karitane to Warrington, a distance of about 12km, and then hopefully hitch a ride back to start. Despite topo maps and Google Earth images, I was still largely unsure of what I was getting myself into. Armed with a wetsuit, canyoning shoes, drybags and a bit of common sense, I set off south. Travel was good in most places, with lots of boulder hopping. Unfortunately I quickly managed to lose my printed maps, which would have helped me keep track of the geology and my progress along the coast.

Thanks to good planning I reached the hardest headland just as low tide peaked. This was a rocky 100m long headland heavily dissected by vertical-walled fissures. I started to climb up and around these obstacles but realized there was no immediate way to get back down beyond. So I went back to the start and put on my wetsuit. I had to start by traversing on pretty challenging rock, with my feet just above the crashing waves. Seaweed holdfasts made quick and desperate footholds between good rock holds. After this I had to swim or wade across several gaps. Here I spent considerable time learning the timing of the waves and waiting for my opening. It took me about a half hour to go these 100m!

The coastline then relinquished itself and soon I found myself back in the sandstone where I found three small sea caves up to 30m long, some with delicate formations and graffiti dating to 1951. Further on I passed several large landslide deposits. There was much more basalt and volcanics than I was expecting which generally made for more challenging coastline. Several portions of coast required me to carefully climb over or under house-sized boulders. These sections were really enjoyable with good rock to hold onto and many interesting features including tidal rapids, squeezes, swims, gap jumps and chimney climbs. Encountering cornered sea lions underneath boulders was enough to get the blood rushing. At one point I came across an entire cliff and shore platform of columnar basalt, some of the finest I had ever seen. Shortly before sunset I reached the sandy Warrington Beach and walked the streets up to Coast Road where I eventually caught a ride back to Karitane from a lovely Maori lady as the sun set. It was a good adventure and a more interesting stretch of coast than I would have guessed.




Start of the interesting headland


Boulders are larger than they appear



Tory Canyon Cave June 6

Unable to convince anyone to do the trip I wanted to do, I decided to tag along on a trip to an obscure and seldom-visited/found cave called Tory Canyon. Armed with someone who had been there only a year before, we thought we had a decent chance of actually finding it. A long, but pleasant, stroll in wet West Coast bush and light rain across tannin-brewed rivers and creeks found us in the general vicinity of the cave where overhangs, arches, bluffs and sculpted rocks line the gently cascading creek. Then the search began. Caves are easy things to lose in West Coast bush, but we were assured that the hole we were looking for was quite sizable, which led to much puzzlement as to why we could not find the cave. After realizing we needed to go a bit further up the creek before deviating up the correct side valley, we eventually found ourselves looking up at the impressive 15m by 15m arch entrance to Tory Canyon Cave. Oddly enough, the cave's dimensions rapidly diminish to a comparatively narrow canyon with a little bedrock stream. Some small waterfall climbs found us looking up a tomo skylight entrance. Continuing on we came to more squeezes and crawls and several branching passages. One of us did a short climb to discover a new entrance not marked on the survey. Once our curiosity was adequately satisfied, we headed out and began the somehow longer and wetter walk back to the car. Several of the party expressed amazement that we actually found the cave, sentiments I wish were made aware to me before I joined them! It is a beautiful region I will have to return to explore further.






Returning to the entrance

Babylon June 5

I co-led a youthful group of 5 into Babylon Cave. Although I would have preferred to go somewhere I have not been before, I thought this a good opportunity to check some leads I had in the back of the cave. The cave has an impressive trunk passage that ends at a enormous rockfall with a fortunate hole that leads down into the continuation of the cave. We climbed up Ray's Reach, an exposed climb/traverse leading to the decorated upper level, much less scary now that new bolts and a traverse line have been installed. The group then de-booted and de-suited and went for a stroll through the very pretty Naked Lady Series. Then we went back down Ray's Reach to probe a way through the terminal breakdown pile. We systematically ruled out over a dozen different possibilities and I checked out some further holes in the floor to no great advancement. Ditching packs, we crawled/stooped our way down the impressively muddy Shady Lane. We all had a great appreciation for the slurping sound effects. I went quite a distance down this passage to where water nearly reached the ceiling- I was not so keen in this instance, especially with my headlamp with loose wiring. Although leads still remain, particularly in the upper levels, I am much less optimistic about finding a back entrance. It was a good trip anyway.


Ray's Reach


In the Naked Lady Series

Cascade Coast & Tops May 27-June 3

8 days of backpacking through the heart of my field area without a single drop of rain. If you asked me before I would have said it was impossible!

What a stellar trip! An 8 day off-trail loop traversing rivers and ridges, bush and beaches. It was 8 glorious days of geologic bliss. My boots were even dry most of the time!

Do not let the photos mislead you. Despite dry skies and low rivers, it was still a demanding trip. We absolutely had to make the most of every bit of daylight as not only did we need to travel 120km, but I also had to find the time to look at the geology along the way. This meant waking up before dawn and being ready to walk at first light (8AM), usually until well after it got dark at 5PM, sometimes hiking as late as 7PM to reach a reasonable camp spot. The upside to the cold and dark winter months- generally more stable weather and manageable sandfly populations.

To take advantage of the favorable forecast, this trip began with a 3:30AM departure from Dunedin and a long drive in the dark until we hit sunrise somewhere around Haast. While the east coast was getting hammered with weeks of rain and extensive flooding, west of the divide it was sunny skies and fine weather when we arrived. Although there had been a major storm on the West Coast mid-week prior, as evidenced by the large tree trunks not present on river banks a week before, the rivers were surprisingly low, lower in fact than I had ever seen. This was great news considering so much of this trip hinged on being able to cross rivers.

The route we chose, despite having all the makings of being a classic (shhh!), is only done on average once a year. The route is a 120km circuit, only 15% on tracks, the rest following either deer trails, ridges, rivers or coastline. We decided to do the route clockwise, which got the harder, more remote Cascade River crossing out of the way and gave us a better chance of good weather crossing the tops of the Gorge Plateau.


The route. Red dots mark the Alpine Fault. 10km grid.

This trip would allow me to do some touch-up fieldwork along the Cascade, scout for a future rafting trip down the river, document recent fault scarps crossing the Gorge Plateau, do some reconnaissance in Durwards Creek (which best I know has not been visited by a structural geologist), acquaint myself with the stratigraphic sequence exposed along the coast and verify previous mapping of the area (which definitely has room for improvement).

This would be a faster, lighter, more streamlined breed of fieldwork than I have been accustomed to. Since this was an 8-day backpack trip, weight mattered greatly and so my field gear was limited to a compass, map, field notebook, GPS and camera. I only sampled the most important rocks, frequently deciding that detailed photos were a lot lighter than rocks to carry (I took a lot of photos!). Because we had a large amount of ground to cover in the short winter days, my field notes had to be succinct, often leaving vague descriptions I could decipher later via outcrop photos. That said I still managed to come home with several kgs of rocks!

And so we set off. Traveling through dry bush was such a delight. We made great time going along the lower Cascade, easily crossing Woodhen Creek. Above Woodhen Creek, the Cascade River has abandoned its river bed and carved a new channel straight through the bush- we both considered this 1km walk up the middle of a dry river bed an eerie 1km of freebie travel. We then entered the dark lower gorge of the Cascade with its deep blue waters, frothy whitewater and sizable boulders. At one point we found ourselves clinging to weakly-rooted plants as we attempted to traverse subvertically bushed slopes to detour the worst of the gorge. We continued on well into the dark, eventually finding a suitable campsite in the gorge. I remember falling asleep thinking how weird it was to be a day's journey into the wilderness when I was in Dunedin just that morning.

Day 2 found us surrounded by frost, which would be a frequent occurrence most mornings of the trip. We found a very easy place to cross the Cascade River, which I learned was not one of my favorite things to do early on a frosty morning. We then continued up river through familiar territory to me, and then found the good spur ridge which made easy (but relentless) travel of the 800m elevation gain up to the start of the Gorge Plateau. Here we broke out of the bush into land reminiscent of a golf course. We crossed "fairways" of discontinuous swamps and meadows with tarns surrounded by stunted beech trees, the "rough" that was to be generally avoided. With our good luck the swamps were frozen at this altitude, providing us easy and dry travel across what would otherwise have been unpleasant swamp. We camped adjacent to a fault scarp and witnessed a fiery sunset on the already red ultramafic rocks of the Olivine Range. A cheeky kea kept sneaking up on our camp well into the starry night.


Going up the Cascade


Sub-alpine beech trees and the Olivine Range






Fault scarp in left foreground



Day 3 was perhaps my favorite as we traversed a 12km long ridge through the Olivine Wilderness with endless views of the coast, Southern Alps, the Darrans, the undulating tussocky slopes of the Gorge Plateau and spectacular views of one of my favorite mountains anywhere, the mystical Red Mountain. Granted it was a bit cold and windy, but the sights kept my mind sidetracked from such inconveniences. From one vantage you could pretty much see our whole 8 day loop. Along the way we passed some spectacular fault scarps including very impressive scarps of the Hollyford Fault System.

Although Red Mountain is not particularly tall at 1700m, it stands alone and demands full attention. This former chunk of the Earth's mantle sits between creamy pastels of serpentinized ultramafics and a snowy backdrop of blue schist mountains. It is hard to take your eyes off of and gives one a strange, almost ghostly, sense of place when looking at it. Photos do not do it justice. Best I know there is no Maori name for the mountain, which is a shame- I bet they would have had a great name and story for it. This is a place I really hope to return to and one with great geology to follow up on. We reluctantly left the tops via aptly-named Telescope Hill and camped at a very fortuitous (but alas, dry) campsite a few hundred meters below bushline.


More fault scarps










Fault scarp! Note far side has gone up and to the right.


Frozen moss and tarnlet




Telescope Hill Trig

Day 4 we continued down the hill, faithfully following my GPS down discontinuous ridges to Durwards Creek. Here we ditched the packs thrice (resulting in sighs of relief) and explored nearby creeks for traces of the Alpine Fault. Although the fault trace itself appears to be buried by omnipresent glacial, river and landslide deposits, some interesting Australian Plate fault rocks were documented and collected. Durwards Creek was pleasant travel, but demanded caution as the boulders had unusually low coefficients of friction. Eventually we reached the Pyke River and the start of the track to Big Bay just as the light began to fade in the darkening bush. Here we made the decision to continue hiking the 8km to Big Bay by headlamp along the rutted ATV track. Fortunately the track was easy to follow as an ATV had used it recently and we stayed to it the whole way (veering off the track would involve a nightmare scenario of trying to navigate in the dark through a swamp). Crossing the Dry Awarua gave me strong flashbacks to wandering up a dry desert wash under a starry sky. We made great time as going fast kept us warm and put us that much closer to food and sleep. We arrived at Big Bay Hut at 9:30PM where I slept wonderfully. In the end we made the right decision to continue on to Big Bay in the dark as this was pretty much the only stretch of the trip that would be feasible to do at night (and was least interesting with no geology), and helped us gain enough ground that we had amazing places to sleep the next 2 nights.


Durwards Creek

The next 3.5 days we walked the coast over surprisingly varied terrain of large boulders, small boulders, cobbles and sand beaches with the occasional bush sidle to bypass cliffs. The stretch of coast from Big Bay to Awarua Point was particularly plagued with uber-slippery ultramafic rocks. A heel injury made this travel significantly more treacherous. Sidle tracks are marked with fishing bouys, which seem to wash ashore in abundance. Crayfish Rock was a welcome lunch respite as it was curiously devoid of sandflies. Along much of this coast we followed the remnants of a 1970s bulldozed mining road from the Cascade to the Pyke. The road is essentially a discontinuous boulder-free strip of beach in the intertidal zone. It is hard to imagine it ever functioned as a road! This coastline was wild and immensely satisfying. I was brimming with a sense of adventure and at times felt I could have been a 100 years back in time. Something in the low light on the red boulders and the clouds flirting with the hills enhanced these feelings. I enjoyed a beautiful sunset as we approached the home stretch to Hackett River, where we were brutally ambushed by sandflies while crossing the river. Here we found a superb campsite beneath giant cabbage trees, had a driftwood fire and a much needed bathe in the river.


Awarua Point looking very distant


Crayfish Rock


Big Bay. Old "road" in foreground.




"Shangri la"



Day 6 we hiked along my two favorite stretches of coast. The beauty was in the details between the Hackett River and Ryans Creek where the waves have sculpted the sandstone rocks into exquisite and seemingly-deliberate shapes revealed only at low tide. The bit of coast surrounding the Gorge River area is probably the most spectacular, with its high hills, gorged river mouth, limestone bluffs and large offshore rocks. We arrived at the Gorge River Hut in early afternoon giving us a bit of time to explore the area. Next door to the hut is the residence of the Long family who have the distinction of being New Zealand's remotest family. Robert Long has lived in this humble house 2 days travel from a road for 30 years! He was later joined by wife, son (17) and daughter (14), the latter two of which have lived their whole lives at the Gorge River. A pretty incredible story and people I would have really enjoyed meeting. Unfortunately the Long family were not home (as we later found out they were in Dunedin!), so hopefully another time. They live off the land as best they can and have an impressive garden. Fences, hammocks, rugby goals and even a 2m tall toy helicopter made out of driftwood recall the craftiness of the Swiss Family Robinson. I think I partly understand the attraction of this place to them. We checked out some small stalactited caves in a limestone bluff nearby and then enjoyed a fantastic fire in the cosy Gorge River Hut.


Social limpets










Wish I knew where half these rocks came from...




House of the Kiwi Family Long


The Steeples

At the start of day 7 we borrowed the Long's leaky dinghy to cross the Gorge River and continued up the coast. I found some interesting rocks at Cutter Rocks where I was once again abused by sandflies. Stretches of this beach had very steep banks of beach cobbles which we walked on top of. The waves would rush up the steep side, lose momentum, then rush back down carrying cobbles down with them as they made a distinctive clattering/grinding noise that is hard to describe. We ran into a group of 3 trampers (people!) at Sandrock Bluff and continued on to Cascade Bay where sunset forced us to camp on the only suitable place we could find, a tent-sized patch of grass a touch above high tide.








Cascade Bay




The track in the Lower Cascade

We got an early start the last day as we had over 20 km to travel. We walked the few kilometers to the Hope River and then along the surprisingly pleasant (but seemingly endless) 4WD track through the bush. Across farmed flats with distant views, we eventually reached the Cascade River, which we once again were fortunate to be able to cross with ease. Shortly after crossing, we hitched a ride back to our car with the good farmer who farms the south side of the river, who spared us walking the least interesting bit of the whole trip.

I was obviously limited in what I could accomplish geologically, but the trip was successful in that I was able to do some reconnaissance of a large portion of my study area so that I have more specific goals for future fieldwork. I collected some good structural data and I think the samples I did collect should prove to be very interesting. Aside from being some of the most enjoyable fieldwork to date, this trip was also some of the nicest backpacking I have ever done. Thanks to field assistant Lara. Photos of me were taken by her.