Drilling Lake Ohau

Lake Ohau site map

Lake Ohau site map

In February 2016, we are carrying out a research programme of scientific drilling on Lake Ohau. Two sites will be drilled, which you can see on the map. The timing of events may vary due to weather and logistics, but the drilling is scheduled to take place between 18 February and 4 March. More information can be found here.

Latest News:

Updates on the project can be found below. For the latest news articles and community events on the project, please see the Media & Outreach page.

Update 4 (7 March 2016): Drilling is complete! At approximately 6:00 AM Thursday 3rd of March the night shift drill crew hit rock bottom - literally. The hydraulic piston corer recovered Ice Age gravels at 80 m below lake floor. The drilling has been a complete success with recovery of the full Ice Age to modern geological record at two sites. We have found leaf and woody material from deep in the section for radiocarbon dating to help accurately date the record. The Drill barge and support boat will be removed from Lake Ohau by Tuesday 8th of March. You can see a short fly-over video of the drilling operation here.

We are obviously thrilled at the outcomes of the project. A big thanks to the drilling operations team, the science and support team and the local Twizel and Ohau community for their efforts and support.

Piston core

Setting up the next piston core.

The rig at night

Beginning the final night shift.

Core hand-over

Core hand-over after collection.

Final Ohau cores

Final cores recovered from 80 m deep.

Update 3 (29 February 2016): The first core site is a complete success! We started coring hole A on Monday and finished coring hole B on Wednesday, resulting in two 42 m long cores in the refrigerated storage container at our site office on the lake shore. Cores from the two holes are offset by approximately 80 cm per run so we have a complete record to the base of the sedimentary sequence. Thin sediment layers (laminations) persist down to approximately 41 m below the lake floor. The first indication of gravel, likely to have been carried by icebergs from the retreating Ohau glacier, appears below 38 m. By 41 m we encounter gravels deposited at the end of the last Ice Age when the glacier was close to the position of the terminal moraines found along the southern margin of the lake. We are confident we have a complete record spanning from the end of the last Ice Age approximately 17,000 years ago to the present day, with laminations preserved throughout the record.

We are currently waiting for the Norwesters to die out so that we can move the barge to the second, deeper water site and hope to have coring underway there in the coming week.

Core examination

Sediment from the end of the corer is examined on board the Beryl Brewin.

X-ray image of core

An x-ray image of core at 41.8 m depth. This image was collected using a mobile x-ray machine set up in the site office.

Mobile x-ray of core

The mobile x-ray machine operated by scientists in the site office.

Core curation

Core curation aboard the Beryl Brewin.

Webster Drilling operating the drill rig

Webster Drilling staff operate the drill rig in perfect weather conditions.

Water siplling out of drill pipe

Water spills out of the drill pipe on board the barge.

Update 2 (20 February 2016): Our new anchors have arrived and look like they will hold an ocean liner! We have tested the piston corer on land and all is well. The blustery northwesterly winds are causing a fair bit of chop on the lake, making conditions unsuitable for drilling and the barge is currently moored at its storm anchorage near Port Bryson. However, the weather forecast looks better for the next couple of days, with light winds and sunny skies. We hope to continue our “sea” trials and position the barge over our first drill site tomorrow.

Fun Facts:
Drill Barge: 27000 kg
Beryl Brewin: 11000 kg
Lake Ohau is living up to its name

Update 1 (18 February 2016): So far so good! We have launched the drilling barge and its support vessel with the help of a 25 tonne crane. The barge is now loaded with drill pipe and we are awaiting some stronger anchors to better resist the famous Ohau wind. We plan to test the hydraulic piston corer on land today and if the new anchors do their job, we could be testing the complete coring system by the weekend.