02658nmc a2200241 4500 20260520010331.0 260224s xxu CD I116 64 0015469 Sedimentología y perfiles de rayos gamma de la formación pozo D-129 (aptiano) en la Sierra de San Bernardo, Chubut 10/11/2016 ; 10/11/2016 25 p. Sedimentology and gamma-ray logs of the Pozo D-129 formation (Aptian) in the Sierra de San Bernardo, Chubut The study provides an outcrop analogue of productive hydrocarbon succesions of the uppermost part of the Pozo D-129 formation (Aptian) in the Golfo San Jorge basin. Although widely distributed in the subsurface of the basin, the Pozo D-129 formation is just exposed in three areas of the San Bernardo Fold Belt; this contribution presents the result of a sedimentological analysis carried out in the Sierra Silva (43 m thick) and Codo del Senguerr (140 m thick) anticlines. Facies analysis allowed the identification of thirteen lithofacies, which were grouped in three main lithofacies associations: (A) deep lacustrine, (B) sub-litoral lacustrine, and (C) shallow lacustrine. The later association consists of four sub-associations: C1 (carbonatic lake), C2 (distributary channels), C3 (distributary mouth bar) and C4 (interdistributary bay). Incomplete shallowing-upward cycles are common in both study areas, evidencing sedimentary progradation. Total and spectral gamma-ray (GR) measurements were obtained using a hand-held device. In Sierra Silva the shape of the U and total GR logs is similar, reflecting that minerals containing U are responsible of most of the emissions of this rocks; diagenetic enrichment of U occurred in a 4,5 m thick section, with measurements up to 500 ppm of U (378 g/tn de U3O8). At Codo del Senguerr, Th and K measurements in fine-grained rocks display better correlation with the total GR log than U, evidencing a different source of radioactive minerals. Integration of sedimentology and gammaray measurements bring data and lithological correspondences that could be useful for regional correlations and subsurface facies models. CONGTP Paredes, José M. 55748 Allard, José O. 55749 Foix, Nicolás 765 Álvarez, Bruno 55750 Olazábal, Sabrina X. 55751 Congreso de Exploración y Desarrollo de Hidrocarburos (9no. : 2014 nov. 3-7 : Mendoza) 54287 189824 189824 https://biblioteca.iapg.org.ar/ArchivosAdjuntos/CONEXPLOR2014/455-Sedimentologiayperfiles.pdf 0 0 0 0 257643 BAAB BAAB CD I116 64 0015469 2026-03-06 200062070 0 CD I116 64 0015469 200062070 2026-03-06 00:19:59 2026-03-06 ARCHIVO