The oldest Ordovician foraminifers (Oepikodus evae conodont Zone, Floian)

NESTELL, G.,; HEREDIA, S.; MESTRE, A.; BERESI, M.; GONZÁLEZ, M.

GEOBIOS

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Año: 2011 vol. 44 p. 601 - 608

0016-6995

The oldest foraminifers of the monothalamous species Amphitremoida longa Nestell 16 and Tolmacheva and A. laevis Nestell and Tolmacheva are found in the San Juan 17 Formation together with conodonts of the Oepikodus evae Zone of the Floian, the 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 17 Formation together with conodonts of the Oepikodus evae Zone of the Floian, the 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 17 Formation together with conodonts of the Oepikodus evae Zone of the Floian, the 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 17 Formation together with conodonts of the Oepikodus evae Zone of the Floian, the 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 17 Formation together with conodonts of the Oepikodus evae Zone of the Floian, the 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 17 Formation together with conodonts of the Oepikodus evae Zone of the Floian, the 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 17 Formation together with conodonts of the Oepikodus evae Zone of the Floian, the 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 17 Formation together with conodonts of the Oepikodus evae Zone of the Floian, the 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the oldest record for 20 foraminifers in South America. The foraminifers, species of which were originally 21 described from the Lower Ordovician of northwestern Russia, are found in shallow high 22 energy carbonate platform deposits in the Precordillera with a North Atlantic province 23 conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta 24 region is interpreted as a succession ranging from shallower tidal deposits to carbonate 25 crinoidal shoaling bar deposits. 18 second stage of the Lower Ordovician, in the Salagasta 2 section, southern 19 Precordillera, Argentina. These discoveries also represent the