The best way to learn geology is in the field. Recently, I was one of several leaders on our upper level field course to New Zealand. My first year on the trip and excitingly, the first year the trip did both the North and South Island. As faculty, we got to go a couple days early for a pre-trip to scout out the South Island (the new part of the trip for our group)- and what a success!!
We successfully located a marine sediment limestone outcrop (pictured above!; all those microscopic plankton floating around in the ocean can make for some impressive rocks given lots and lots of time!) that was deposited during the Paleocene and Eocene (many many million years ago). Known as the Amuri Limestone, this particular feature has many outcrops along New Zealand’s south Island. Near the transition between the Paleocene and Eocene was an interesting period in Earth’s climate history known as the PETM or Paleocene-Eocene Thermal Maximum. Scientists are particularly interested in this time period because of a large release of CO2 on very short (geologically!) timescales- potentially having implications on predictions for what the much much faster modern CO2 release from humans may mean in terms of climate. The PETM was characterized by a warmer Earth, even the deep ocean was several degrees warmer than present!
We also successfully found access to the K-T boundary! For my non-geology readers, this is exciting for many reasons. 1) The K-T boundary occurred ~65 million years ago, thats a long time. Its very hard to find outcrops that old. Only about 3 easily accessible outcrops from the K-T exist. 2) The K-T boundary was one of Earth’s great extinction events- the one that killed off the dinosaurs (not to mention most other life) and 3) the extinction event was caused my a large meteor slamming into Earth, slamming into Earth near the Yukatan peninsula to be more exact. How often do you get the opportunity to touch that much biological/chemical and geological history all at once?
We also scouted the glacial features around Mt Cook (Aoraki) before picking up the students and starting their trip with a couple of days in the Aoraki region. A highlight was the Tasman Glacier, which is retreating rapidly. No glacial lake was associated with the Tasman prior to the 1980s, now there is a large enough lake to take speed boats on (Look close to see the boat in the image below). The boat tours allow you to get up close to the icebergs calving off the Tasman glacier and bring you the the foot of the glacier. The guides have to adjust daily to account for new ice bergs and rolling risks! Remember only about 10% of an ice berg is visible above the surface of the water! That other 90% is pretty threatening to a small boat if the berg starts to roll!
And then to Christchurch, to see the ongoing challenges they face in recovering from the 2011 earthquake that devastated the city. Shown below are shipping container containment walls visible throughout the area around Christchurch to try to prevent debris from landslides and on going quakes (we missed another large quake by only about a week) from taking out the roads.
And geology trip to New Zealand would be complete without the North Island, and a hike across the Tongariro Crossing! Welcome to middle earth, and a new appreciation of just how much effort is involved in crossing it! My phone claims I did about 200 flights of stairs that day, and I believe it. An all day adventure, the crossing takes you through some spectacular volcanic landscapes, and if you have the time (and not a large group) you can take a detour up to the summit of Mt Doom (Mt Ngauruhoe). Later on in the crossing you see the red crater (last photo below), the emerald lakes (first photo below), and the crater from the 2012 (!!! still very active!!!) eruption.