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