Days 8-10: Kracking the Kase in Kaikoura

Day 8: The Journey from Westport to Kaikoura

We left Westport on another rainy, bleak west-coast morning to travel back to the east coast. After a trip to the local rubbish disposal, we began driving through Lewis Pass. Our first stop was the alpine fault (the boundary between the Australian and Pacific plates) where we saw the 80-foot wall running perpendicular to the fault line. The idea is that when there is movement along the fault, the wall will split, but it is currently still intact because the last known earthquake in that area was in the 1600s. 

Then we took a quick detour to see a scenic view that Lydia recommended but sadly was mostly obscured by the rain. Then we stopped at Culverdon and met up with our fellow geologists, Sandy and Josh. We had a quick lunch at a café and then made out way to Rebecca’s farm. Along the way, we saw loads of sheep and free roaming cows. Once at the farm, we took a walk to see a unique feature. It was a fault scarp. This was caused by an earthquake that occurred in 2016 and has been an area of geologic interest ever since. After thoroughly analyzing the scarp, we were able to determine that it was left-lateral strike-slip fault. We also saw evidence of the fault not just in the fault scarp, but also by the displacement of fence lines on the property. Last we ventured a little further into the farm to see a waterfall and the remains of a mass wasting event, both caused by the 2016 earthquake. It was very valuable to be able to see real-life repercussions of tectonic activity.

 

Day 9: Kicking it in Kaikoura Part 1 

The day started off with a short drive to see a mass wasting event, but instead, we were more captured by seeing the nearby seal colony. 

After at least fifteen minutes of looking at our furry friends, Josh recaptured our attention by explaining some of the unusual geologic features in the area. Adjacent to the seal colony, there were tall hills that had clear signs of mass wasting. Vegetation had been displaced and was shown in patches across the hills, rather than evenly distributed. Josh explained how this mass wasting was caused by the Kaikoura earthquake and this created many jobs in the geoengineering field. We saw people working on this area and attempting to make it safer in case of future events. We then traveled back into town to take a glance at the Kaikoura peninsula to begin our two-day mapping activity! Josh, Lydia, and Guil walked us through many outcrops, giving us a chance to analyze their distinct features and make inferences about their character and depositional environment. We started at each outcrop using the STC method and Josh even brought his trusty HCl to test for CaCO3 content. We enjoyed a nice lunch on the Warf, but not long after a nasty storm blew in and the weather headed south. With only a few stops left, we hurried to finish our observations and quickly wrapped up for the day. 

Day 10: Kicking it in Kaikoura Part 2

This was the big day. The culmination of everything we learned. The mapping activity… Our mapping activity took place in the South Bay and we were given six hours to determine the stratigraphic layout of the units we had seen the previous day. We stumbled about looking for contacts and recognizable features in order to distinguish which rocks matched up from what we saw from the day before. 

After hours of examining the outcrops and contacts closely, we determined that there were five visible sections. The oldest section was “saltine,” and was defined by its meter size concretions. The next section was “cottage cheese” and was characterized by its calcite mineral veins and silt-sized particles. The contact between these two sections was sharp, but showed evidence of a right-lateral strike-slip fault. The next visible section was “woody,” which displaced local deformity and lack of the black grains that were visible in previous layers. The contact between the two sections was covered with water and not visible, so we are unsure of exactly where it lies and what the nature of it is. 

The penultimate section was labeled “dragon stone” and also showed evidence of local deformity and was characterized by having black bands of coarse grained material in between the more prominent cream colored layers. The contact between “woody” and “Dragonstone” was sharp and provided evidence of a time gap based on the angular unconformity it showed. The final and youngest visible section was “seal rock” and was characterized by lack of divided surface weathering and a dark gray weathered surface color. The contact between these two layers was almost a meter wide in some areas and showed breccia. 

There was also multiple left-lateral strike-slip faults present. During our geologic journey, we were also given the task of taking strike and dip measurements every 75 meters or so to add to our final map. After exploring and gathering all our observations, we headed back to the office to complete our mapping activity. 

It was a challenging day, but we were rewarded with a medium-warm hot tub party at the end of the night.

Beth and Ellie!