Middle- to late-Holocene relative sea-level changes at Puerto Deseado (Patagonia, Argentina)

Abstract

Stratigraphic, morphologic and radiocarbon data from Puerto Deseado coastal area (Santa Cruz Province, Argentina) indicate that the Holocene coastline formed in response to the discontinuous aggradation of coarse gravely beaches since c. 6300 cal. yr BP related to a progressive falling of relative sea level. Beach ridge crests crudely approximate to the sea level showing at least three steps of aggradation and relative sea-level lowering. Two inactive abrasive notches at c. 7.9 and 3.4 m a.s.l. have recorded this sea-level trend, suggesting two important phases when sea level was stationary. This allows the estimation of a rate of relative sea-level fall in the last c. 3500 years of c. 1.8 mm/yr. Moreover, notches and morphological data indicate that the crest of the beach ridges exceeded the sea-level height by c. 2 +/- 0.5 m. This value provides a reasonable regional estimate to be applied to produce comparable relative sea-level curve for Atlantic Patagonia coast

Abrasive notches along the Atlantic Patagonian coast and their potential use as sea level markers: the case of Puerto Deseado (Santa Cruz, Argentina)

“…It is shaped in the form of rocky marine terraces sparsely covered by Quaternary marine and subaerial deposits Zanchetta et al, 2014). It is shaped in the form of rocky marine terraces sparsely covered by Quaternary marine and subaerial deposits Zanchetta et al, 2014).…”

“…The study area and the location of the11 abrasive notches analysed (red points). On the northern coast there are littoral deposits of Quaternary age that seaward cover a modern intertidal-lower supratidal shore platform (Feruglio, 1950;Codignotto et al, 1988;Zanchetta et al, 2014). com/journal/espl Figure 2.…”

“…The volcanic and volcanoclastic substratum dominates the area of Puerto Deseado settlement and part of the Rio Deseado river mouth. It is shaped in the form of rocky marine terraces sparsely covered by Quaternary marine and subaerial deposits Zanchetta et al, 2014). A rocky Figure 1.…”

Tectonic Processes along the South America Coastline Derived from Quaternary Marine Terraces

“…In the Chubut Province, Holocene beach plains were dated in Puerto Lobos (Codignotto, Kokot, and Marcomini, 1992), Caleta Valdés (Codignotto, 1983;, Chubut River estuary (Monti, 2000), Bustamante Bay (Codignotto, Kokot, and Marcomini, 1992;Schellmann, 1998a,b), and Solano Bay (Codignotto, Kokot, and Marcomini, 1992). At the Deseado River estuary, gravel ridges indicate a sea-level drop since 6300 YBP of about 4-7 m (Zanchetta et al, 2014). Along the Santa Cruz Province similar highstands were recorded at San Julián Bay (Schellmann and Radtke, 2003) and Río Gallegos (Gonzá lez Bonorino et al, 1999).…”

Late‐pleistocene wedge structures along the patagonian coast (argentina): chronological constraints and palaeo‐environmental implications

“…; Zanchetta et al . and references therein). Particularly relevant here are gravel and sandy gravel marine deposits belonging to the MIS 5 transgression ( c .…”