PERSONAL DE APOYO
MARTINIONI daniel Roberto
artículos
Título:
Late Albian inoceramid bivalves from the Andes of Tierra del Fuego: Age implications for the closure of the Cretaceous marginal basin.
Autor/es:
E. B. OLIVERO; D. R. MARTINIONI
Revista:
JOURNAL OF PALEONTOLOGY
Editorial:
The Paleontological Society
Referencias:
Lugar: Boulder; Año: 1996 vol. 70 p. 272 - 274
ISSN:
0022-3360
Resumen:
SUMMARIZED CONTENT: At the southernmost tip of South America, a thick pile of deep marine volcaniclastic rocks called the Yahgan Forrnation was deposited during the Early Cretaceous in a small marginal basin developed between the continent and a Pacific facing volcanic arc. North and northwest of Tierra del Fuego, in the adjacent Austral or Magallanes Basin, this unit is laterally replaced by coeval, fine-grained deposits representing basinal, slope, and platforrn marine settings. The geometry of the basins changed markedly with a cornpressional event that produced the tectonic inversion of the marginal basin and the formation of a retroarc foreland basin in front of the rising cordillera. Closure of the marginal basin and strong deforrnation of the Yahgan Formation apparently occurred in the mid-Cretaceous however, the timing of the opening and closing of the basin is poorly constrained because of the scarcity of fossil evidence. So far, a Late Jurassic-Neocomian age was favored for the Yahgan Formation on the basis of the record of belemnites and ammonites. Also, the timing of the transition from rnarginal to foreland basin is not well documented. On the basis of indirect evidence the initiation of the fore1and basin stage was assigned to the Albian in the Última Esperanza region of Chile and to the Late Cretaceous in northern Tierra del Fuego. Recent field work by the authors in the area has resulted in the first record of diagnostic late Albian inoceramids in the Yahgan Formation. The objecfive of this paper is to document this fauna and to briefly discuss its implications on the control of the timing of the transition from marginal to foreland basin in the area.