How Ice Needles Create Spontaneous Zen Gardens

Live Science

Some of the most breathtaking zen garden patterns on the planet owe their existence to an unlikely artist: thousands of tiny "ice needles."   Credit: Quan-Xing Liu of East China Normal University

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00:00In high-latitude permafrost environments and high-altitude mountains, there are a large

00:12number of mysterious regular surface patterning, also known as patterning, such as the Qinghai-Tibet

00:20Plateau and other freezing regions in China, the Svobod Islands in Norway in the Arctic

00:27and the Alpine regions in Ethiopia. The patterned ground is made up of different kinds of stones

00:34and soils, some arranged in polygonal net, stone circles, and others in strapped spatial

00:43patterns. The origin of these regular patterns has long been puzzling scientists, but recently

00:51this enigma is starting to be solved. Scientists now attribute the spontaneous regular patterns

01:00to a process called spatial self-organization. In the periglacial environment, winds gathering

01:08together with soil-freezing thawing cycles are speculated to drive the aggregation and

01:14separation movements of granular particles in the soil, which eventually result in a

01:20sordid spatial patterns of stones on the land surfaces.

01:32This idea has been sparked by theoretical and empirical studies in physics, chemistry,

01:38biology and ecology. However, it is notoriously difficult to test this idea in the field.

01:47The geomorphological systems in cold regions often evolve at extremely slow rates, largely

01:54forbidden human observers to record the processes. Many existing numerical models have suggested

02:02that differential frost heave and radial expansion of the fine-grained soils can lead to the

02:08movement of surface particles to the margins of the plugs and the formation of the self-organized

02:14patterns. This mechanism can reproduce a variety of large-scale sordid patterns, such as polygons

02:22and sordid circles, but direct experimental evidence for this model is still lacking.

02:30Scientists have long speculated that needle ice formed in the permafrost layer could play

02:35a role. A new research led by an international team from China, Japan, the US and the Netherlands

02:43revisited this old idea with brand new evidence and theory. The researchers designed an elegant

02:51experiment system that allows for the formation of needle ice in well-controlled lab conditions.

02:58This system can mimic a time machine with which the observers can push the fast-forward

03:04button to speed up the process of land surface evolution within a microcosm. Within a couple

03:10of weeks, the researchers can now observe the years or even decades-long process happening

03:16in nature. They use video camera and computer program to automatically track the movement

03:24trajectory of every single stone and reproduce such observed processes in computer with mathematical

03:31models. The researchers found that driven by the freezing-thaw cycles in soils, the

03:36granular particles migrated towards the stone-rich areas from stone-poor areas. This is exactly

03:43the process where a variety of older spatial patterns of stones arises from.

03:50This group of scientists have replicated the experiment numerous times with all kinds of

03:56settings of needle ice properties and stone field concentration. They put together these

04:01nonlinear relationships between different needle ice height and stone field concentration

04:07to demonstrate that the geomorphological pattern formation process has the same physical principle

04:13as that underpins the water-oil separation process.

04:27Known as phase-separation mechanism, the phase-separation theory perfectly reproduced

04:32the different types of sorted patterns and found that the activity of needle ice plays

04:37a dominant role in shaping this pattern ground. What makes the scientists more exciting is

04:44that their phase-separation model can also perfectly reproduce the similar sorted patterns

04:50found in the Martian boulders by curiosity. Can this seen as another evidence reinforcing

04:57the existence of soil-water on Mars? Does this mean freezing-thaw cycles also drive

05:03the evolution of Martian landscapes? It's still too early to answer this question, but

05:10the study does open many opportunities to look into geological and geomorphic evolution

05:16of Earth-like planets.

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