The watershed of the Seine River in northern France occupies much of the Paris Basin, a long-lived geologic feature that forms the fairly flat landscape of that country. It is about 500 km by 300 km in area, and extends from the Belgian Basin in the northeast south to the Massif Central province.
In the Carboniferous period, the Variscan/Hercynian orogeny occurred in parts of what would eventually become Europe as that landmass collided with Laurentia to form part of the supercontinent Pangaea.
As this mountain building pulse ended, North America and Europe gradually began pulling apart. The Paris Basin sits along a platform: an area at the edge of a craton where the land subsides enough to allow the ocean to lap up onto the continent. Beginning in the Permian as the continents began separating, the waters of the ocean started occasionally intruding far enough onto the continent to deposit marine sediments throughout that basin.
A couple deep faults beneath the Paris basin have assisted in allowing subsidence over the past 200 million years, creating additional accommodation space for new sedimentary deposition.
In the early 1800s, Georges Cuvier, whom Wikipedia grants the title “The Father of Paleontology”, spent several years mapping fossils and rock outcrops within the Paris Basin, eventually concluding that the sequences represented alternating pulses of ocean water and fresh water. This work was published shortly after William Smith’s geologic map of the United Kingdom and helped lay out the principles of stratigraphy that would be used to interpret sedimentary sequences around the globe.
Much of the pale white building stone of the City of Lights owes its origin to one of these pulses. The “Lutetian” stage is a subdivision of the Eocene Epoch that occurred about 41-47 million years ago. It is named for the Paris Basin: Lutetia was the Roman/Gallic name for the community that would eventually become Paris.
The official marker for the Lutetian on the geologic column is established in a quarry near Paris where blocks of Lutetian aged limestone are quarried to be used in building stone throughout the area, giving photos like this one their distinctive color. The sediments of the Paris Basin also contribute to the development of soil throughout the area, creating the fertile soils of northern France, and they have also been tapped for limited oil and gas resources.
Image credit: http://bit.ly/1N3DLoi
References: A past post on the topic: http://on.fb.me/1HPOJWH http://bit.ly/20TjzJE http://evolution.berkeley.edu/evolibrary/article/history_08 http://tmblr.co/Zyv2Js1xF_Sf- http://bit.ly/20TjENB http://bit.ly/1PHouYR
