Jurassic 201.3 Mya - Named after Jura Mountains of France & Switzerland

• William Smith’s faunal succession - At the begging of the 1800s he continued the work of the coal measures cross-section of John Strachey. Smith noted the massive amount of marine fossils including reptiles, ammonites while exploring the newly exposed earth from coal mining and canal digging across western England. He noticed that certain types of fossils only occurred in certain layers of rock. He got so familiar with the section that he could tell what rock he was in just by looking at the fossils. He continued his work towards mapping the entire surface of England and Wales.

• PRINCIPAL OF FAUNAL SUCCESSION - is a fundamental law of biostratigraphy, the science of dating rock formations by referencing a known sequence of fossil evolution. The principle states that layers of sedimentary rock contain fossilized flora and fauna, these fossils evolved over geologic time in a specific way and that evolution is captured in the rock record with changes over time recorded vertically from lower to higher formations. The fossils can be compared over broad horizontal distances. Diagnostic Species, once that evolved rapidly can be most useful to pinpoint specific ages of rock.

Evaporite deposits in the GOM

Spreading ridges - asymmetric shape, one side significantly thinned relative to the other.

Many rifted margins, that turned into passive margins, are covered in Cretaceous sediments