Presenting at the 2024 Geoscience Society of New Zealand Annual Conference offered me a delightful opportunity to catch up with friends and colleagues in Dunedin, my other side of the world home. It was a grand nostalgia tour overall with lots of long missed faces. A quiet morning in the conference schedule aligned with a low tide, giving an opportunity for a morning hike to a very rarely visited beach with Alan, one of my former PhD advisors. This Caversham Sandstone cliff-lined beach is only possible to visit by a steep grass-covered slope accessible through the active seaside Blackhead Quarry. I managed to get in touch with the quarry manager to secure us permission and the weather held out to a merciful intermittent spitting. My hope was to visit the interesting sea cave chamber at the far side of the beach past the first headland, which I mapped and last visited...in 2010! When we showed up at the quarry office it turned out the manager was quite eager to show us a few interesting outcrops and so we actually started with a quarry tour. We checked out the exposure of the Blackhead Fault which juxtaposes the Caversham Sandstone against the thick pile of basaltic lava that is being quarried. We then drove down towards the bottom of the quarry to check out a few interesting breccia outcrops and the fantastic columnar basalt that makes up the remaining headland of Blackhead.
After the quarry tour we parted with the manager and drove up to the edge of the quarry nearest our slope to the beach. I brought my trekking poles which came in handy for both of us to descend the steep wet grass slope. We made our way slowly, soon reaching the basalt cobble beach, atypical for Dunedin. Awkwardly we clambered over the shifting cobbles towards the far end of the beach as seagulls swirled above us.
Occasionally we came across pieces of kelp washed up on the shore that were completely coated in gastropods jockeying for a prime eating position which made an unusual sight. We dodged the occasional wave as we made our way along. When we got to the headland that splits the beach in half I was quite disappointed to see that for even this current low tide there was no way on without swimming. The headland had a sea cave tunnel through it in the past but we found this filled up to the ceiling with large cobbles we weren't going to be moving and less sand on the beach meant that it was not feasible to round the headland (which I had also done in the past). I shrugged and apologized to Alan; I wish I got to show him the cave beyond but oh well.
For our return we decided to walk across the top of the beach cobbles instead of along the foreshore slope. This also had some animal surprises as we encountered no fewer than twenty seagull nests built directly on the cobble beach, most with one to three just born chicks or eggs with beak pecks that would likely hatch by the end of the day. It was quite surprising to see them out in the open and apparently was a predator free beach.
We went back up the slope, out the quarry and drove on to the conference in time for morning tea and the rest of the day's events. I was thrilled to get to spend the time with Alan. The day ended quite nicely with a run through Ross Creek and reservoir with Genevieve and my old officemate Tammo, and then a nice catch up with my friend Lara over dinner as we worked to plan our next week of travel. The weather forecast made a very clear case for us to head north and not south! Many thanks to all those mentioned.
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