ISLA Federico Ignacio
The Gravels of the Rio De La Plata: The Holocene Beaches of Bella Vista, Uruguay
ISLA FEDERICO; ESPINOSA, M
JOURNAL OF COASTAL RESEARCH
COASTAL EDUCATION & RESEARCH FOUNDATION
Lugar: Tampa; Año: 2021 vol. 37 p. 987 - 992
The R´ıo de la Plata has a r´ıa-type estuary, with a coastal plain dominated by ﬁne to very-ﬁne sands to the south and a tectonic coast to the north dominated by ﬁne to coarse sand. Although the headlands of the river were dominated by ﬂuvial processes related to the deltaic lobes of the Parana River, the Parana´ Guaz ´u, and Parana´ de las Palmas, the outer estuary is subject to wave action that increased signiﬁcantly during storms from the SE. Wave statistics conﬁrmed a littoral drift responsible for the spits at the outlets of afﬂuent rivers deﬂected to the west (Solís Grande,Solís Chico). At the northern Uruguayan coast the interval between Bella Vista and Las Flores is composed of gravel that is described here. Bella Vista beach has two berms; the upper berm is partially covered by eolian sands. Las Flores beach consists of a single berm where gravels segregate upward and sand moves toward the river coastline. The storm berm of Bella Vista includes ﬁner gravels (3?6 cm) whereas the gravels from the tidal berms (both beaches) are coarser, from 6 to 15 cm. According to the Zingg diagram, oblate and tabular gravels abraded by the wave action dominate. Considering old photographs, these gravel berms are stable and relicts from the highstand of the Middle Holocene. They were, therefore, derived by waves from submerged deposits originally derived from the Complex Sierra de las Animas.