In general, irregular periods are very common during the perimenopause. The most common early menstrual irregularity noticed in the perimenopause is a shortening of cycle length.
Abiogenic petroleum origin. Abiogenic petroleum origin is a term used to describe a number of different hypotheses which propose that petroleum and natural gas are formed by inorganic means rather than by the decomposition of organisms.
As the Earth cooled, geological activity caused gases from the Earth's interior to come to the surface to form a second atmosphere, composed mostly of carbon dioxide, ammonia, and water vapor.