Early cementation and accommodation space dictate the evolution of an overstepping barrier system during the Holocene

Falco, Giovanni De; Antonioli, Fabrizio; Fontolan, Giorgio; Presti, Valeria Lo; Simeone, Simone; Tonielli, Renato

doi:10.1016/j.margeo.2015.08.002

Cited by 48 publications

(34 citation statements)

References 47 publications

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“…1a). The gulf represents the western boundary of the Campidano graben, a Pliocene -Quaternary structural depression oriented NW-SE (De Falco et al, 2015), filled by transitional, marine and continental deposits. The area is part of the transitional environment, bounded seaward by sandy shoreline and eastward by the Tirso alluvial plain.…”

Section: Study Areamentioning

confidence: 99%

Mid to late Holocene environmental changes along the coast of western Sardinia (Mediterranean Sea)

Melis

Depalmas

Rita

et al. 2017

Global and Planetary Change

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Multiproxy analysis composed of biostratigraphy and pollen analysis allowed reconstructing the palaeoecological and palaeoenvironmental evolution of the Tirso river coastal plain in Sardinia (NW Mediterranean) in the last 6 millennia. We demonstrated that interplay between littoral and fluvial processes have significantly controlled the environmental evolution of the area and have played a key role in the pattern of historical and prehistorical settlements of this wide portion of western Sardinian coastline. At the end of Neolithic period (ca. 6.0 to 5.5 cal. ka BP) the area close to the shoreline was most likely characterized by large coastal lagoons intermittently connected to the open sea. Such saltwater influence is corroborated by faunal and pollen assemblages found in the landward portion of the Tirso coastal plain up to 2 km inland from the modern shoreline. Our data robustly document the end of the transgressive trend at ca. 5.5 cal. ka BP, and a dominant fluvial sedimentation since Final Neolithic period. At this time, a progradational trend started, causing the seaward migration of shoreline and, consequently, of the barrier-lagoon system. The major landscape modification tracked along the last 6 millennia may also explain the low density of historical and prehistorical remains in the Tirso coastal plain, especially if compared to the nearby rocky area of Sinis Peninsula densely inhabited since the Neolithic. Our data further provide new insights into the Relative Sea Level (RSL) evolution in this sector of the Mediterranean. In particular, we improved the mid-Holocene RSL record in Sardinia, where only scarce data were previously available

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Section: Study Areamentioning

confidence: 99%

Mid to late Holocene environmental changes along the coast of western Sardinia (Mediterranean Sea)

Melis

Depalmas

Rita

et al. 2017

Global and Planetary Change

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“…Of relevance to this study, late Pleistocene/early Holocene sealevel pulses are believed to be coincident with the deposition of relatively small remnant barriers found at steeply sloping sites in South Africa and Sardinia (De Falco et al, 2015;Pretorius et al, 2016). Future modeling explorations may therefore provide insight on whether autogenic partial overstepping interacting with sea-level pulses could play a role in driving deposit size/spacing on high-gradient coastlines.…”

Section: Discussionmentioning

confidence: 96%

“…Submerged and remnant transgressive barrier island deposits can be a major component of shelf bathymetry and stratigraphy, commonly found on continental shelves across the world (Rampino and Sanders, 1980;Mellett et al, 2012a;De Falco et al, 2015). Formation of these barrier deposits is typically attributed to changes in allogenic forcing, such as changes in the rate of sea-level rise, alteration of sediment supply, or variation in antecedent topography (Cattaneo and Steel, 2003;Storms et al, 2008;Mellett et al, 2012a).…”

Section: Introductionmentioning

confidence: 99%

Interaction of Sea-Level Pulses With Periodically Retreating Barrier Islands

2019

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Submerged barrier deposits preserved on continental shelf seabeds provide a record of paleocoastal environmental change from the last glacial maximum through the Holocene. The formation of these offshore deposits is often attributed to intermittent periods of rapidly rising sea levels, especially glacial meltwater pulses, which are expected to lead to partial or complete drowning-overstepping-of migrating barrier islands. However, recent cross-shore modeling and field evidence suggests that even for constant sea-level rise and shelf slope, the internal dynamics of migrating barriers could plausibly drive periodic retreat accompanied by autogenic partial overstepping and deposition of barrier sediment. We hypothesize that the interaction of periodic retreat with changes in external (allogenic) forcing from sea-level rise may create novel retreat responses and corresponding relict barrier deposits. Specifically, we posit that autogenic deposits can be amplified by an increased rate of relative sea-level rise, while in other cases internal dynamics can disrupt or mask the production of allogenic deposits. Here, we model barriers through a range of autogenic-allogenic interactions, exploring how barriers with different inherent autogenic periods respond to discrete, centennial-scale sea-level-rise pulses of variable magnitude and timing within the autogenic transgressive barrier cycle. Our results demonstrate a diversity of depositional signals, where production of relict sands is amplified or suppressed depending on both the barrier's internal dynamic state and the pulse magnitude. We also show that millennial-scale autogenic periodicity renders barriers vulnerable to complete drowning for relatively low pulse rates of rise (<15 mm/year).

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“…The expected sea level rise by the year 2100 for the study area ranges from 0.54 to 1.3 m (Antonioli et al, 2017;De Falco et al, 2015). This will determine an adaptation of the whole coastal system.…”

Section: Discussionmentioning

confidence: 97%

Biogenic sediments from coastal ecosystems to beach–dune systems: implications for the adaptation of mixed and carbonate beaches to future sea level rise

et al. 2017

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Abstract. Coastal ecosystems produce and store carbonate particles, which play a significant role in the carbonate dynamics of coastal areas and may contribute to the sediment budget of adjacent beaches. In the nearshore seabed of temperate zones (e.g. Mediterranean Sea and South Australia), marine biogenic carbonates are mainly produced inside seagrass meadows. This study quantifies the contribution of biogenic sediments, mainly produced in Posidonia oceanica seagrass meadows and secondarily in photophilic algal communities, to the sediment budget of a Mediterranean beachdune system (San Giovanni beach, western Sardinia, western Mediterranean Sea). A set of geophysical, petrographic and sedimentological data was used to estimate the sediment volume and composition of the beach-dune system as a whole. The San Giovanni beach-dune system contains 3 797 000 ± 404 000 t of sediment, 83 % (3 137 000 ± 404 000 t) of which is located in the coastal wedge, 16 % (619 000 ± 88 000 t) in the dune fields and 1 % (41 000 ± 15 000 t) in the subaerial beach. The sediments are composed of mixed modern bioclastic and relict bioclastic and non-bioclastic grains from various sources. The system receives a large input of modern bioclastic grains, mainly composed of rhodophytes, molluscs and bryozoans, which derive from sediment production of present-day carbonate factories, particularly P. oceanica seagrass meadows. Radiocarbon dating of modern bioclastic grains indicated that they were produced during the last 4.37 kyr. This value was used to estimate the longterm deposition rates of modern bioclastic sediments in the various beach compartments. The total deposition rate of modern bioclastic grains is 46 000±5000 t century −1 , mainly deposited in the coastal wedge (39 000 ± 4 000 t century −1 ) and dunes (7000 ± 1000 t century −1 ), and 46 000 t represents ∼ 1.2 % of the total beach-dune sediment mass. Carbonate production from coastal ecosystems was estimated to be 132 000/307 000 t century −1 , 28 % (15 % / 34 %) of which is transported to the beach-dune system, thus significantly contributing to the beach sediment budget.The contribution to the beach sediment budget represents a further ecosystem service, which our data can help quantify, provided by P. oceanica. The value of this sedimentsupply service is in addition to the other important ecological services provided by seagrass meadows. The dependence of the beach sediment budget on carbonate production associated with coastal ecosystems has several implications for the adaptation of mixed and carbonate beaches to the loss of seagrass meadows due to local impacts and the changes expected to occur over the next few decades in coastal ecosystems following sea level rise.

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Early cementation and accommodation space dictate the evolution of an overstepping barrier system during the Holocene

Cited by 48 publications

References 47 publications

Mid to late Holocene environmental changes along the coast of western Sardinia (Mediterranean Sea)

Mid to late Holocene environmental changes along the coast of western Sardinia (Mediterranean Sea)

Interaction of Sea-Level Pulses With Periodically Retreating Barrier Islands

Biogenic sediments from coastal ecosystems to beach–dune systems: implications for the adaptation of mixed and carbonate beaches to future sea level rise

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