Controls on Deep-Water Stratigraphic Architecture
B.W. Romans, A. Fildani, S.M. Hubbard, 2009. "Controls on Deep-Water Stratigraphic Architecture", Stratigraphic Evolution of Deep-Water Architecture: Examples of controls and depositional styles from the Magallanes Basin, southern Chile, Andrea Fildani, Stephen M. Hubbard, Brian W. Romans, J.A. Covault, W.H. Crane, A. Bernhardt, Z.R. Jobe, D.A. Armitage, J.C. Fosdick, M.R. Shultz, J. Clark, D.R. Lowe, S.A. Graham
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The effect of inherited attenuated crust from the closure of the predecessor backarc basin led to a relatively narrow orogenic belt during the Magallanes foreland development and a short distance from arc to foredeep. The attenuated crust heritage also provided continuous basinal subsidence (contributed to by fold-thrust belt loading and ophiolitic block obduction),which permitted long-lived (>20 my) deep-marine deposition and accumulation of >4000 m of turbiditic sediment that filled the basin axially in a north to south direction (Figs. ii.1A and C). Three distinct formations that reflect three distinct phases of deep-water deposition with different stacking patterns are featured in this document: the Punta Barrosa Formation, the Cerro Toro Formation, and the Tres Pasos Formation.
These three formations were deposited with contrasting stratigraphic architectures that we relate to two general factors: (1) variability in amount and type of source material (i.e., changes in provenance and/or staging area) and (2) variations in the basin shape throught time. Changes in the source and staging areas are represented by clear sedimentological differences, including the sandstone-and mudstone-dominated Punta Barrosa Formation with banded slurry beds, the conglomeratic channel-fill deposits of the Cerro Toro Formation, and the sandstone packages and mudstone-rich mass transport deposits of the Tres Pasos Formation slope system (Figs. ii.1B and C; see following page).
Basin morphology controls the general lay-out of depositional systems (e.g., channel dimensions, degree of confinement, dispersal patterns, etc.), which influences the distribution of sediment and resultant stacking patterns. We suggest
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Stratigraphic Evolution of Deep-Water Architecture: Examples of controls and depositional styles from the Magallanes Basin, southern Chile
This large format (11 × 17 inch) all color outcrop atlas and field guide was produced for the SEPM Research Conference held in Chile in February, 2009. It contains a wealth of information on the world class deep water outcrops of the Cretaceous of the Magallanes Basin in the Ultima Esperanza District, Chilean Patagonia. This book covers the significant outcrops in the region the Punta Barrosa Formation, CerroToro Fm., and the Tres Pasos Fm.