Final answer:
Marine fossils are found in deserts due to past geographical changes where seas once existed. Over time, these areas dried up or were raised, and erosion exposed fossilized sea life. The Delaware Basin in west Texas is one such example of an ancient marine environment now observed as a fossil-rich desert.
Step-by-step explanation:
Marine fossils can end up in the desert due to the geological history of the Earth, where areas that are now arid deserts were once covered by oceans. Tiny sea plants and animals died and settled on the ocean floor, becoming buried under layers of sediment over time. Geological processes such as plate tectonics and erosion could elevate these former seabeds and expose the fossils within them.
The Delaware Basin, for example, was once an ancient reef system home to various marine life forms, which over time became exposed through tectonic activity and erosion, resulting in the fossil-rich mountains that we see today in regions of west Texas.
Fossils preserved in sedimentary layers are often exposed by weathering forces, such as wind and water erosion, which can rapidly remove surrounding materials that have buried them for eons, as seen in the 2020 discovery in California. Erosion processes can significantly influence how and where fossils are found and provide clues to the paleoenvironments where these organisms once thrived.
Ultimately, changes in the planet’s climates and geography, combined with eons of geological activity, can transform marine habitats into dry land, accounting for marine fossils found in current desert climates.