A recent study revealed a sedimentary layer composed of fine soil and sand beneath most of the island's ice sheet. The study confirmed that this layer, which ranges in thickness from 5 meters in some areas to over 300 meters in others, reduces friction between the ice and the bedrock, allowing the massive ice sheets to move more rapidly as meltwater seeps down.
“If larger quantities of water reach the bottom of the ice sheet, these deposits could weaken the ice’s cohesion, accelerate its flow, and increase its loss to the ocean,” said researcher Yan Yang of the University of California, San Diego. She added, “This means that some areas of Greenland may be more vulnerable to the effects of climate change than current models suggest.”
The study indicated that the distribution of sediments is not uniform, as the thickest layers are found in areas where the ice bed is warmer and wetter, while the sediments are thinner or absent in colder areas, which explains the varying speed at which glaciers break up.
Scientists have warned that the presence of these layers could hinder the exploitation of the island's natural resources, including oil, gold, copper, graphite, and rare earth elements, as drilling operations require a solid, stable base. Previous studies have shown that thick layers of soil and sand, reaching hundreds of meters in thickness, can clog and damage drilling equipment, causing frequent operational shutdowns.
To gather the data, Yang's team used more than 370 seismic monitoring stations spread across Greenland over the past two decades. The team analyzed the transmission of seismic vibrations through the ice and soil, and by comparing the results with computer models that assume ice is directly on the rock, the scientists were able to pinpoint the location and thickness of the hidden sediment layer with precision.
The findings indicate that the Greenland ice sheet is less stable than previously thought, and that its melting could accelerate global sea-level rise, place significant constraints on the extraction of natural resources, and increase the challenges to any economic or strategic operations in the region.
These findings take on added significance in the context of US ambitions in the Arctic, where the Trump administration seeks to annex Greenland due to its strategic location and rich resources.
The study was published in the ournal Geology.
