Deposition and stratigraphic architecture of an outcropping ancient slope system: Tres Pasos Formation, Magallanes Basin, southern Chile

Abstract

The Tres Pasos Formation, Magallanes Basin, Chile, represents the deposit of a submarine slope depositional system. The formation is approximately 1500 m thick where exposed in the Ultima Esperanza district of southernmost Chile. It is characterized by a basal turbiditic sandstone unit up to 200 m thick that shows a north-to-south, proximal-to-distal facies evolution from turbidite channel-fill complexes to sheet-like sandstone units. This unit is interpreted as having been deposited at or near the base of slope. Overlying the basal sandstone unit is approximately 500 m of amalgamated mass transport complexes, fine-grained strata, and channelized and non-channelized turbidity current deposits, collectively comprising the middle part of the formation. Mass transport complexes exert a primary control on the character and grain size of turbidite sandstone bodies in the basal and middle part of the formation. In the southern part of the study area, a 300 m thick coarse-grained unit interpreted as a turbidite channel-fill complex partially replaces the middle part. The upper part of the formation is approximately 500 m thick and consists primarily of fine-grained strata. Failure scarps and thin turbidite channel-fill units are present in this upper part, interpreted as upper slope deposits.

The Role of Mass Wasting In the Progressive Development Of Submarine Channels (Espírito Santo Basin, Se Brazil)

“…Turbidity flows can be captured by depletion zones on the headwall domains of basal scars (Shultz et al 2005;Kertznus 2009;Kneller et al 2016), where bathymetric lows develop due to sediment evacuation and local extension (e.g., Lewis 1971;Martinsen and Bakken. 1990;Frey Martinez et al 2005;Bull et al 2009).…”

“…To better understand accommodation space as a function of MTD geometry and internal structure, the interaction between MTDs and turbidity currents has been documented in a number of studies based on outcrop analogues (e.g., Shultz et al 2005;Lucente and Pini 2008;Jackson and Johnson 2009), seismic data (e.g., Kertznus 2009;Bernhardt et al 2012;Masalimova et al 2015;Ortiz-Karpf et al 2015;Kneller et al 2016), bathymetric data (Corella et al 2016), well and core data (Eggenhuisen et al 2010;Corella et al 2016), and numerical models (Stright et al 2013). These studies have shown that turbidity flows can deposit upstream and above MTDs (e.g., Bernhardt et al 2012;Ortiz-Karpf et al 2015;Corella et al 2016), or, instead, can be erosive to create large-scale scours above MTDs (e.g., Shultz et al 2005).…”

“…These studies have shown that turbidity flows can deposit upstream and above MTDs (e.g., Bernhardt et al 2012;Ortiz-Karpf et al 2015;Corella et al 2016), or, instead, can be erosive to create large-scale scours above MTDs (e.g., Shultz et al 2005). Furthermore, turbidity flows can be diverted by topographic highs created by MTDs, leading to the generation of new sediment routes (Hansen et al 2013;Masalimova et al 2015;Kertznus 2009;Corella et al 2016).…”

Sedimentology, architecture, and sequence stratigraphy of coarse-grained, submarine canyon fills from the Pleistocene (Gelasian-Calabrian) of the Peri-Adriatic basin, central Italy

“…Similar deposits are commonly inferred to represent a transitional stage within the evolutionary continuum from slumps to fully homogenised muddy debris flows (López-Gamundì, 1993;Tripsanas et al, 2008;Strachan, 2008) and referred to as mass-transport deposits or mass-transport complexes (e.g. Posamentier, 2003;Pickering and Corregidor, 2005;Shultz et al, 2005).…”

Sedimentary Facies and Architecture of a Gigantic Gravelly Submarine Channel System in a Cretaceous Foredeep Trough (the Magallanes Basin, Southern Chile)

“…The Cerro Toro Formation includes a lens of Lago Sofia conglomerate (LSC), which extends for more than 100 km from north to south of hemipelagic mudstones and thin interbeds of turbidite sandstones deposited during the late Cretaceous (Cenomanian-Campanian) (Cecioni 1957;Katz 1963). The formation is underlain by deep-water clastic sediments of the Punta Barosa Formation (Albian-Cenomanian) and overlain by a shallowing-upward clastic succession of the Tres Pasos Formation (Santonian-Maastrichtian) (Katz 1963;Scott 1966;Winn and Dott 1979;Shultz et al 2005). A study of foraminiferal assemblages indicates that the water depth in the Magallanes Basin was 1000−2000 m during the deposition of the Punta Barosa and Cerro Toro Formations (Natland et al 1974).…”