Depositional environment of Stelloglyphus llicoensis isp. nov.: a new radial trace fossil from the Neogene Ranquil Formation, south-central Chile.

Abstract

ABSTRACT. Stelloglyphus llicoensis isp. nov. is a large radial, discoidal to ellipsoidal trace fossil with a central shaft and single to bifurcating branches radiating from different levels. A 30 m thick measured section of the Ranquil Formation at Punta Litre contains an associated trace fossil assemblage including Zoophycos, Chondrites, Phycosiphon, Nereites missouriensis, Lockeia siliquaria, Psammichnites(?), Parataenidium, Ophiomorpha, and Rhizocorallium, some of which reworked the Stelloglyphus traces. The sedimentology, together with micro-and macrofossils and the associated trace fossil assemblage, suggest that the succession was deposited in an outer continental shelf to slope environment in subtropical to tropical waters.

Tectonic controls on the Maastrichtian-Danian transgression in the Magallanes-Austral foreland basin (Chile): Implications for the growth of the Southern Patagonian Andes

“…The fine-grained nature of FA1 and degree of bioturbation related to the Zoophycos ichnofacies suggest a low-energy and open marine environment below storm-wave base (Bann and Fielding, 2004;Buatois and Mángano, 2011). The thick mudstone facies (Fm) and internally graded units (Fh and Sm) reflect settling of hemipelagic mud and deposition by mud-rich, low-density turbidity currents (Shultz et al, 2005;Romans et al, 2009;Malkowski et al, 2017a) in an outer shelf setting, as supported by the slump and contorted structures, as well as the abundant presence of Stelloglyphus llicoensis commonly found in this kind of environments (Le Roux et al, 2008). The relative abundance of silt and sand grain sizes, as well as storm-(Shcs) and wave-generated (Sw) structures in FA2, indicate that the depositional setting was shallower than that of FA1, above storm wave base and close to fair-weather wave base (Rossi and Steel, 2016).…”

Unravelling Phanerozoic evolution of radial to rosette trace fossils

“…-This consists of several very closely or partially overlapping spaced multi-level tunnels radiating from a central shaft ( Fig. 5E; Vyalov 1964;Le Roux et al 2008). This is a shallow-to mid-tier trace fossil that is preserved as negative epirelief and full relief (Fig.…”

“…5E). It is probably a backfilled burrow system of a stationary deposit-feeding animal (Le Roux et al 2008). A lower Cambrian occurrence of Stellophycus was mentioned by Crimes (1992), but the absence of description or illustration precludes confirmation.…”

“…recorded in offshore deposits of the Lower Pennsylvanian Atoka Formation, Oklahoma, United States (Chamberlain 1971a). The youngest record corresponds to deep-marine deposits of the Pliocene Ranquil Formation, south of Concepci on, Chile (Le Roux et al 2008), and probably it is present in the recent.…”