If you have any questions about this list of geological events, please contact Tom Sienkewicz at Monmouth College, Monmouth, Illinois at toms@monm.edu.




4.6 billion years ago-----------------Earth Formation

4.0 billion years ago-----------------Oldest Igneous rocks

3.5 billion years ago-----------------Oldest sedimentary rock/stromatolites

2.7 billion years ago-----------------Abundant algae plants

1.2 billion years ago-----------------First known animals(jellyfish)


600 million years ago-----------------First animals with hard parts (shells) (first abundant fossil evidence)

425 million years ago----Ordovician Period--Petroleum and natural gas formed in ancient oceans

350 million years ago----Devonian Period--Petroleum now found in dry land areas like Pennsylvania

280 million years ago----Mississippian/Pennsylvanian Period--coal deposits formed

230 million years ago----Permian Period--uplift of Appalachian Mountains (source of iron ore for steel industry)


180 million years ago----Jurassic Period--dinosaurs abundant

70 million years ago----end of Mesozoic Era--Uranium ore deposits


60 million years ago-----------------Mammals dominate land (some are early relatives of farm animals of today)

25 million years ago-----------------Last oil deposits to form in areas such as Persian Gulf, Russia, Mexican Gulf

19th/century (1800's)----------------Industrial Revolution-England (metal used in manufacturing and steam engines)

1903-----------Wright Brothers--First Airplane

1908-----------Henry Ford Model T (leads to assembly line production of automobiles)

1959-60---Nuclear submarine Nautilus sails under North Pole coal widely used in 20th/century to produce electricity forenergy in homes and factories.

1974-----------energy crisis---higher prices for fuel

1986-----------more countries using fossil fuel, modernizing (more people using fuels) supply may not exceed needs by 2000, when the greatest need will exist.

Back to Monmouth College Classics Dept. Homepage