Right now, science can slim down potential oil reserves with stunning accuracy — particularly in the case of shale oil, discovered embedded inside sedimentary rock. By learning sediments in China’s Sichuan Basin, researchers discovered that variations within the Earth’s orbit might help prospectors higher predict the place shale oil is most probably to kind.
In contrast to crude oil, which swimming pools in subterranean reservoirs, shale oil is discovered inside shale rocks. Shale types from layers of fantastic sediment deposited in historic lakes or seas, the place low-oxygen situations permit natural matter to build up and, over tens of millions of years, generate oil throughout the rock.
Milankovitch cycles are regularly occurring variations in Earth’s orbit and tilt that influence our planet’s long-term climate, including the timing of ice ages. The cycle of orbital eccentricity — the stretching and shrinking of Earth’s elliptical orbit — operates over hundreds of thousands of years.
The rock record revealed that during periods of high orbital eccentricity, stronger seasonal contrasts produced warmer, wetter conditions that boosted nutrient delivery to lakes. Biological productivity surged, leading to the deposition of finely layered, organic-rich mudstones — the types of rocks most favorable for shale oil.
When eccentricity decreased, the climate shifted toward drier conditions. Lake levels dropped, sediment supply changed, and sand-rich deposits spread across basin slopes and into deeper waters, transported by gravity-driven flows. Together, these alternating wet and dry phases created a predictable stacking pattern of rock types across the basin.
The study also showed that sediment accumulated at an average rate of just over four centimeters per thousand years, allowing researchers to align individual rock layers with specific orbital cycles. Using a newly-developed framework based on this research, scientists can better identify where high-quality shale reservoirs are likely to occur.
It’s worth noting that shale oil is not only a fossil fuel, however can also be extracted by means of hydraulic fracturing, or fracking, which carries environmental concerns. Nonetheless, till the world absolutely transitions to renewable vitality, oil will stay a serious vitality supply — and mixing astronomy with geology is rising as one of the vital highly effective instruments for locating it.
The group’s analysis was revealed within the Journal of Paleogeography (Chinese edition) on Sept. 30, 2025.
