Pierre-Olivier Combelles Posted February 19, 2017 Share Posted February 19, 2017 (edited) Hi! In the same (calcareous) region of Lake Junin (or Lake Chinchaycocha, in quechua), in the High Central Andes of Peru, where I was investigating Maca (Lepidium meyenii Walpers) I found in tne 1990's this nice coral fossil specimen at the altitude of 4200/4300m. Measure below in cm. What do you think about it ? Thank you in advance ! Warmfully Pierre-Olivier Combelles Institut Andin d'Etudes Ehnobiologiques (France) Edited February 19, 2017 by Pierre-Olivier Combelles Link to comment Share on other sites More sharing options...
Guguita2104 Posted February 19, 2017 Share Posted February 19, 2017 Hi! It looks like a branching coral. Do you know the age of the layers? Regards, Link to comment Share on other sites More sharing options...
Pierre-Olivier Combelles Posted February 20, 2017 Author Share Posted February 20, 2017 (edited) No, I don't know. I found it on the ground (the puna). This region is calcareous. Edited February 22, 2017 by Pierre-Olivier Combelles Precision Link to comment Share on other sites More sharing options...
Pierre-Olivier Combelles Posted February 23, 2017 Author Share Posted February 23, 2017 Measure below the coral in cm. Link to comment Share on other sites More sharing options...
FossilDAWG Posted February 23, 2017 Share Posted February 23, 2017 Hi Pierre-Olivier, Your coral is a nice specimen, but unfortunately corals cannot be identified just from a side view. You need to see the internal structure, showing both cross and longitudinal sections. Can you photograph any parts of the specimen that would show any detail like that? Close-up views of the top and the bottom would also perhaps be helpful. For a really confident identification, thin sections would have be cut and mounted on slides. It is possible that your specimen has been replaced by silica, that is suggested by the way it has weathered out of the encasing limestone. Unfortunately silicification often obscures the original detailed structure, though there is no way to know for your specimen based on the one photo. There are thousands of described species of coral, which is why so much detail is needed for a confident identification. Don 3 Link to comment Share on other sites More sharing options...
Pierre-Olivier Combelles Posted February 25, 2017 Author Share Posted February 25, 2017 On 23/02/2017 at 11:51 PM, FossilDAWG said: Hi Pierre-Olivier, Your coral is a nice specimen, but unfortunately corals cannot be identified just from a side view. You need to see the internal structure, showing both cross and longitudinal sections. Can you photograph any parts of the specimen that would show any detail like that? Close-up views of the top and the bottom would also perhaps be helpful. For a really confident identification, thin sections would have be cut and mounted on slides. It is possible that your specimen has been replaced by silica, that is suggested by the way it has weathered out of the encasing limestone. Unfortunately silicification often obscures the original detailed structure, though there is no way to know for your specimen based on the one photo. There are thousands of described species of coral, which is why so much detail is needed for a confident identification. Don Thank you very much Don, for your kind explainations ! This specimen is in my collections in Peru and I am actually in France. But when I shall be back in S. AM., I shall do it with some paleobiologist friends. So, keeping in touch, all the best ! Link to comment Share on other sites More sharing options...
Pierre-Olivier Combelles Posted August 10, 2017 Author Share Posted August 10, 2017 An interesting paper from french IRD (Institut de Recherche pour le Développement) of 2005: The Lower Carboniferous of the western edge of Gondwana in Peru and Bolivia: Distribution of sedimentary basins and associated magmatism Alberto Zapata M. \ Agapito Sanchez F. '. Segundo Carrasco V. 1, Agustin Cardona 2, Jorge Galdos H. 1, Fredy Cerrôn Z. 1, & Thierry Sempere 3 1 Direction of Regional Geology, Instituto Geologico Minero Metalurgico (INGEMMET), Lima, Peru 2 Phd student of the University of Sâo Paulo, Brazil 3 IRD, LMTG, Observatoire Midi-Pyrénées, 14 avenue Edouard Belin, 31400 Toulouse, France 6th International Symposium on Andean Geodynamics (ISAG 2005, Barcelona), Extended Abstracts: 817-820 http://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers09-03/010040372.pdf Would date the fossils of this area and our coral, in the Carboniferous, somewhere between Tournaisien (-358.9) and Serpoukhovien (-323.2). See the extract below ("Junin-Huancavelica Sector"): Ambo Group. As said in the abstract of the paper, we are here in the western edge of Gondwana: "During the Early Carboniferous, the tectono-sedimentary and rnagrnatic configuration of the western edge of Gondwana (Eastern Cordillera of Peru and Cordillera Real of Bolivia, between latitudes 3°S and 24°S; Figure 1) associated a marine and continental sedimentation (Ambo Group), a volcanic arc (Lavasen Formation) and a related plutonism (Pataz-Balsas-Buldibuyo batholith, Higueras pluton , Amparaes and Cadenas granites). " Link to comment Share on other sites More sharing options...
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