Ammonites in the High Andes of Peru

[Pierre-Olivier Combelles]

During the same years (1997-2000) and in the same region of the High Andes of Peru, I discovered the fossil fern and the fossil coral presented in my two other topics:

 

http://www.thefossilforum.com/index.php?/topic/72054-fossil-fern-in-the-high-andes-of-peru/#comment-758432

http://www.thefossilforum.com/index.php?/topic/72061-coral-fossil-of-the-high-andes-of-peru/#comment-758464

 

, I took this picture (slide poorly scanned, sorry) of ammonites in the stone wall of San Pedro de Parish, an old little abandonned church of the beginning of the Hispanic Colony, on the shore of Lake Junin (or Chinchaycocha, en quechua), altitude 4125m.

 

What do you think about it, especially in relation with the branching coral ?

 

Thanks

 

[Pierre-Olivier Combelles]

Lake Junin (orL. Chincaycocha) is on the right, Lima on the left. Peruvian map, 1855.

[JarrodB]

That's cool. 

[Pierre-Olivier Combelles]

The church of San Pedro de Parish, on the shore of Lake Junin (4125 m). May be XVIIe century. The ammonites are on a stone of the abutment at the right side of the entrance. This stone had been especially choosed for its decorative effect, of course...

 

[Pierre-Olivier Combelles]

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 ammonites, 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). "