The geological structure of France goes back 2,000 million, which is the age of the oldest rocks known. After the Pre-Cambrian Orogeny, which is represented in the north of the Armorican Chain, the Caledonian and above all the ian Orogeny formed the crystalline and metamorphic ossature of the country. All that is visible of this now is a few brought into relief after the peneplanation of the greater part of the chain. These are the Armorican Chain, the• Massif central, the Vosges, and the Ardennes. From the end of the Primary Era, some 270m. years ago,succeeding the peneplation phase, a process of subsidence in certain regions, accompanied by the formation of geosynclines in other regions, became evident during the secondary.
Ketersediaan
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Pusat Sumber Daya Mineral, Batubara dan Panas Bumi - Jln. Soekarno Hatta No. 444, Bandung, Jawa Barat
PMB 01 - 1978 Prosiding