1. Introduction
Deserts, often thought of as barren and unchanging, are actually dynamic environments where even the smallest elements, like gypsum crystals, can move and shift. Gravel-sized gypsum crystals, found in certain arid regions, don’t remain stationary; they move across the desert floor, often leaving tracks behind them. This mysterious phenomenon has puzzled scientists for years. But what causes these crystals to move, and how do they travel across such harsh and dry terrains?
2. The Science of Gypsum Crystals
Gypsum is a soft mineral made up of calcium sulfate, often found in dry desert areas. When exposed to the elements, gypsum forms into various shapes, including gravel-sized crystals. In some desert regions, particularly in places like California’s Death Valley or the Sahara, gypsum can form large deposits on the ground, creating a surreal, crystalline landscape. However, these crystals don’t stay put for long—they slowly shift across the desert floor, leaving behind telltale trails.
3. Wind: The Power Behind Crystal Movement
The primary driver behind the movement of gypsum crystals is the wind. In desert environments, winds can blow at speeds strong enough to move loose particles and small rocks. The wind lifts and carries light particles, including sand and gypsum crystals, across the ground. As the wind gusts, the crystals are pushed and rolled along the desert floor, forming patterns that can span over large areas. This process, known as “saltation,” is common in desert landscapes and is responsible for moving a variety of materials, including gypsum.
4. The Role of Surface Moisture
Interestingly, the movement of gypsum crystals is not just about dry winds; moisture also plays a critical role. During brief rainfalls or periods of high humidity, a thin layer of moisture can form on the desert surface. This damp layer makes the ground slightly sticky, which allows the wind to better grip the gypsum crystals and propel them forward. As the moisture evaporates and the ground dries, the crystals can be left in place, having moved only a short distance, or they may continue to be carried by stronger winds until they reach their final resting position.
