The Senèze Maar and Paleontological Site (Massif Central, France): Their Volcanic Context and Studies of Related Tephras

The Senèze volcano is composed of a basanite flow, scoriaeScoriae deposits, phreatomagmatic tuffsTuff and a maarMaar crater. Recent fieldwork and mapping clarify the extension and the succession of these volcanic products. A first phreatomagmatic episode precedes the lavaLava flow which seems accompanied by the deposition of scoriaeScoriae. In a later phase, the maarMaar crater is formed and the main phreatomagmatic tuffs are emitted. The comparative study of the fossiliferous deposits exposed in newly excavated sections and of two other sections reveals the interstratified occurrence of 10 tephras and six reworked tephric layers issued from the Mont-DoreMont-Dorestrato-volcano strato-volcano, 60 km north-westwards. These mainly trachytic products are attributed to the Early Pleistocene pyroclastic activity of the strato-volcano, ca 2.1 Ma. Their distinct composition in the different outcrops evidences the polyphased deposition of the fossiliferous site.