Denver is home to some of the oldest ice in the world. It’s true!
Ice collected from the depths of the coldest regions in the world tell the story of our planet’s history, and those stories are collected and stored right here in Denver.
Here’s all you need to know about the Ice Core Facility here in Denver!
Denver’s ice core facility
What is the NSF-ICF?
The National Science Foundation Ice Core Facility (NSF-ICF) was first established in 1993 as the U.S. National Ice Core Laboratory in Lakewood, Colorado, before being renamed in 2018.
The main purpose of the NSF-ICF is to store, curate and study ice cores from all over the world, most of which are collected from glaciated regions in Greenland, Antarctica and various places in North America. These ice cores are used to study the history of the world through trapped gasses in the ice, and they’re frequently used to gather information on climate change from past millennia.
The NSF-ICF facility itself is massive, with the core storage chamber measuring over 55,000 cubic feet of space. Nearly 13.67 miles’ worth of ice cores are stored in the chamber in a cool -32.8 degrees Fahrenheit, and additional research and exam rooms make up the rest of the sprawling facility.
It’s here that scientists from all over the country come to cut sample slices from ice cores in order to study their chemical compositions, as well as to run the core processing line (CPL) that catalogues any new ice cores arriving from the polar regions.
What are ice cores, exactly?
Glad you asked!
Think of your high school science lessons on geology and sedimentary rocks; you know, the ones that have all those layers and streaks of color. Those layers were created one by one over an extended period of time, and the different colors and chemical compositions of those layers are snapshots of what the surface of the Earth looked like as they were forming. Fossils, petrified wood and imprints of leaves all tell us what type of fauna and flora existed during that time period, and eventually we can start assembling a geological calendar based on the timelines these rocky layers give us.
Ice works the same way.
Over time, layers of snow and snowmelt pile onto each other to create a massive layered sheet of ice. In Antarctica where the ice is thickest, the ice sheet alone (not even counting the land beneath it all!) is almost three miles thick! That means that enough snow has fallen and frozen to climb halfway up Mount Everest. And it’s all ice!
An ice core is collected by drilling straight down into that sheet of ice and removing a solid cylinder of ice. This cylinder shows layers of ice as it’s frozen, melted and refrozen, plus any layers of debris that may get trapped in there. In the same way that a tree’s rings can tell us how much water it had to grow each year, each layer of ice shows a winter or summer season, and the thickness of those layers can tell us how much snow fell during those seasons.
More importantly, these layers of ice can trap tiny little air bubbles in them that are perfectly preserved from thousands of years ago. By studying those pockets of air and their icy layers, scientists can determine things like air chemistry, air temperature and even snow accumulation for that period!
The further down the core is collected, the further back in time one can travel. The oldest ice core yet was taken from Antarctica in 2017, and it dates back nearly 2.7 million years!
How ice cores are collected
Since ice cores are studied for their layers, sites for ice core drilling must be flat and fairly stable. As in, regular snowfall must have fallen on a flat plateau consistently, without any slanting or sliding away.
Essentially, it’s like one of those sand artworks in a glass box, where you can see the colorful layers of sand sitting neatly on top of each other. If that sand was layered like a hill, all the layers would mix and mingle on the sides, while the center remained fairly stable. That center is what ice core scientists are looking for, and the best places to find these consistently icy conditions are in the polar regions like Antarctica and Greenland.
Once the location is chosen, it’s time to drill.
Coring is done by using a rotating pipe with cutters at the end to drill straight down into the ice. Once that section of pipe has cored as much ice as can fit in the pipe, the drill is lifted from the ice and the ice core is removed. The drill is then re-inserted into the drill hole and lowered to drill the next section of ice. The process continues and the drill lowers further and further each time.
Of course, different drills are required for different depths of ice, especially when collecting ice from several miles below the surface! And while there are many models and styles of drills used all over the world, there are three main categories of ice drills.
These drills are powered by hand (using a lever) or a small motor, and are generally about a yard long. These drills can be lowered to a maximum of 130 feet below the surface.
Shallow coring refers to coring anywhere between 130-980 feet below the surface, a process requiring a higher level of technology and manpower. Drills used in shallow coring are suspended by a winch directly above the drill hole, which allows scientists to efficiently and effectively collect sections of ice without requiring heavy equipment.
Deep ice coring
Deep ice coring is anything from 980 feet onwards, with some drills designed to go as far as 2.4 miles below the surface!
These projects are no small matter, as they often take years’ worth of seasonal drilling to reach their required depths. The West Antarctic Ice Sheet (WAIS) Divide ice core project took six seasons of 24-hour drilling to complete, requiring a team of nine drillers and an absolutely massive drill stored in a makeshift warehouse in the heart of the Antarctic.
These drill projects require a near-constant stream of drill fluid running through the hole to keep the walls from freezing together again.
Once the ice cores are collected, they're shipped to the NSF-ICF right here in Denver, where they are stored and protected for scientists all over the world! And the best part is that if you live in our luxury Denver apartments, you can take a tour of this fascinating ice core lab and see them all for yourself (once tour operations are resumed).
Featured photo courtesy Unsplash/Derek Oyen