As graveyards for marine organisms as well as prehistoric plants, reserves can be viewed as mounds of ancient plants. Many bodies of water and oceans have contained this substance which has remained there for thousands of years. The resulting pressure and temperature were caused by the sediments that covered those remains over time. Once the oil had been formed, the pressure and temperature were important factors. Oil is currently being consumed more quickly than it. As a result, oil has been considered a non-renewable resource.