Sea level controls on buried geomorphology within the Swan River estuary during the Late Quaternary

Vast areas of the shallow Adriatic shelf were exposed at the time of the Last Glacial Maximum lowstand. This enabled formation of lakes, river valleys and river floodplains that were submerged during the Holocene transgression. Here we present a study of the karst estuary of the Krka River located in central Dalmatia on the eastern Adriatic coast. The Krka River creates a 23 km long estuary extending north from the &#352;ibenik Channel, over the Prokljan Lake, up to the tufa waterfall Skradinski buk. We used high resolution acoustic methods including sub-bottom profiler (SBP) coupled with multibeam echo sounder (MBES) (MBES bathymetry and MBES backscatter) and side-scan sonar (SSS) to investigate the submerged karst river valley and lake system that existed before the Holocene relative sea level rise. A total of 70 km of SBP profiles and a point cloud of 241 991 638 points in the area of 6.2 km2 were collected during the surveys. Water depth ranges from 5 m b.s.l. in the most northern part of the study area, to 25 m b.s.l. in the southern part of the Prokljan lake.To create a better geomorphological and geological classifications of the seabed, we made a network of 36 ground truthing stations where we sampled sediments with Van Veen grab sampler and obtained underwater images. Sediment samples were analyzed for grain size, bulk density, carbon and nitrogen concentrations, as well as mineralogical XRD analysis and magnetic susceptibility. We combined gathered data with GIS classification tools to create accurate seabed maps of the area. Our results also showed that well-defined submerged river canyon in the Prokljan Lake area was filled with three sedimentary units: fluvial, brackish and marine. Quaternary sediment thickness is up to 15 m. Seabed geomorphology of the investigated area is characterized by many submerged tufa barriers. They are similar to present barriers upstream of the Skradinski buk waterfall. These unique karst geomorphological features, that grow as algae and mosses are encrusted by carbonate, enabled formation of lakes, as well as prevented a marine flooding during the Holocene sea-level rise. The depth of each barrier (4.5 to 12 m b.s.l.), in connection to the onset of marine sedimentation within the estuary, can be used as an indicator of sea level. Barriers are emphasized on the MBES backscatter data as strong reflectors. Grain size of sampled sediments ranges from poorly sorted sand and gravel on underwater barriers to fine silt sediments in the deeper parts of Prokljan Lake. Larger sediment size on barriers is caused by tufa debris while fine silt is sedimented in the deeper parts of the basin. Grain size results vary for different geomorphological provinces, allowing for a more precise (GIS) classification and description of the seabed.This work was supported by the Croatian Science Foundation Project &#8220;Sediments between source and sink during a late Quaternary eustatic cycle: the Krka River and the Mid Adriatic Deep System&#8221; (QMAD) (HRZZ IP-04-2019-8505).

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Submerged landscapes of the eastern Adriatic – from the river across the lake all the way to the sea

10.5194/egusphere-egu21-12177 ◽

2021 ◽

Author(s):

Slobodan Miko ◽

Keyword(s):

Sea Level ◽

Environmental Changes ◽

Late Quaternary ◽

River Estuary ◽

Integrated System ◽

Submarine Channels ◽

Side Scan Sonar ◽

Sedimentary Sequences ◽

Marine Sedimentation ◽

Geophysical Surveys

Submerged paleolandscapes constitute records of long-term paleoenvironmental change, climate, and sea level. To date, there is a very limited knowledge concerning the submerged karst paleolandscapes of the eastern Adriatic coast and the Late Quaternary sedimentary sequences along the eastern part of the Mid Adriatic Deep (MAD). We aim to improve this through the project &#8220;Sediments between source and sink during a Late Quaternary eustatic cycle: The Krka and the Mid Adriatic Deep System&#8221; (QMAD). The QMAD project supports multidisciplinary research by application of the high-resolution geophysical surveys (multibeam, side-scan sonar and sub-bottom profiler), in combination with sedimentological, petrophysical, geochemical (trace elements and isotopes), micropaleontological (ostracod and foraminifera), mineralogical and aDNA techniques. This suite of analyses will enable tracking of the paleoenvironmental evolution from fluvial/lake to deeper marine environments, on a short transect less than 100 km in length (Lake Prokljan in the Krka River estuary to the eastern part of MAD). The submerged Late Pleistocene and Holocene environments that occur include isolation basins, lagoons, deltas, estuaries, submarine channels and shelf. The continuous marine sedimentation during the Late Quaternary is investigated in the MAD. In the case of the central part of the eastern side of the Adriatic Sea (Krka catchment - MAD) these different environments compose an integrated system; thus, they can&#8217;t be analysed separately. The main goals of this project fill the existing gaps in understanding of the climatic and environmental changes, including sea-level related landscape changes and their interplay during the Late Quaternary eustatic cycle. More data on the Pleistocene environments, especially from the region of Krka estuary that was land during the Last Glacial Maximum (LGM), will complete the picture of the evolution and environmental adaptation of Paleolithic humans and their relationship with vegetation changes. Attention is also paid to potential anthropogenic environments, recent sedimentation rates, landscape features and artefacts. All results of the multi-proxy approach applied in this project will eventually be merged into a comprehensive Late Quaternary paleoenvironmental and paleoclimatic reconstruction of the eastern Adriatic landscapes that contribute to the understanding of these changes in the Mediterranean region.

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Sea level controls on palaeochannel development within the Swan River estuary during the Late Pleistocene to Holocene

CATENA ◽

10.1016/j.catena.2017.02.008 ◽

2017 ◽

Vol 153 ◽

pp. 131-142 ◽

Cited By ~ 2

Author(s):

Giada Bufarale ◽

Michael O'Leary ◽

Alexandra Stevens ◽

Lindsay B. Collins

Keyword(s):

Sea Level ◽

Late Pleistocene ◽

River Estuary ◽

Late Pleistocene To Holocene ◽

Swan River

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LATE QUATERNARY SEA-LEVEL HIGHSTANDS OF THE MID-ATLANTIC US COASTAL PLAIN AND SUB-ORBITAL VARIABILITY WITH IMPLICATIONS FOR ICE SHEET SENSITIVITY

10.1130/abs/2016am-281640 ◽

2016 ◽

Author(s):

Robert K. Poirier ◽

◽

Thomas M. Cronin ◽

Miriam E. Katz ◽

...

Keyword(s):

Sea Level ◽

Coastal Plain ◽

Late Quaternary ◽

Ice Sheet

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A global sea-level curve for the late Quaternary: the impossible dream?

Marine Geology ◽

10.1016/0025-3227(95)00057-6 ◽

1995 ◽

Vol 125 (1-2) ◽

pp. 1-6 ◽

Cited By ~ 25

Author(s):

Daniel Jean Stanley

Keyword(s):

Sea Level ◽

Late Quaternary ◽

Level Curve ◽

Global Sea Level

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Molluscan aminostratigraphy of the US Mid-Atlantic Quaternary coastal system: Implications for onshore-offshore correlation, paleochannel and barrier island evolution, and local late Quaternary sea-level history

Quaternary Geochronology ◽

10.1016/j.quageo.2021.101177 ◽

2021 ◽

pp. 101177

Author(s):

John F. Wehmiller ◽

Laura L. Brothers ◽

Kelvin W. Ramsey ◽

David S. Foster ◽

C.R. Mattheus ◽

...

Keyword(s):

Sea Level ◽

Late Quaternary ◽

Barrier Island ◽

Coastal System ◽

Island Evolution ◽

The Us

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Late Quaternary Landscape Dynamics at the La Spezia Gulf (NW Italy): A Multi-Proxy Approach Reveals Environmental Variability within a Rocky Embayment

Water ◽

10.3390/w13040427 ◽

2021 ◽

Vol 13 (4) ◽

pp. 427

Author(s):

Veronica Rossi ◽

Alessandro Amorosi ◽

Marco Marchesini ◽

Silvia Marvelli ◽

Andrea Cocchianella ◽

...

Keyword(s):

Sea Level ◽

Environmental Variability ◽

Late Quaternary ◽

Landscape Dynamics ◽

Last Interglacial ◽

Core Depth ◽

Coastal Bay ◽

Nw Italy ◽

Global Sea Level ◽

Geomorphological Features

The Gulf of La Spezia (GLS) in Northwest Italy is a rocky embayment with low fluvial influence facing the Mediterranean Sea. Past landscape dynamics were investigated through a multi-proxy, facies-based analysis down to a core depth of 30 m. The integration of quantitative ostracod, foraminifera, and pollen analyses, supported by radiocarbon ages, proved to be a powerful tool to unravel the late Quaternary palaeoenvironmental evolution and its forcing factors. The complex interplay between relative sea-level (RSL), climatic changes, and geomorphological features of the embayment drove four main evolution phases. A barrier–lagoon system developed in response to the rising RSL of the Late Pleistocene (likely the Last Interglacial). The establishment of glacial conditions then promoted the development of an alluvial environment, with generalised erosion of the underlying succession and subsequent accumulation of fluvial strata. The Holocene transgression (dated ca. 9000 cal year BP) caused GLS inundation and the formation of a low-confined lagoon basin, which rapidly turned into a coastal bay from ca. 8000 cal year BP onwards. This latter environmental change occurred in response to the last Holocene stage of global sea-level acceleration, which submerged a morphological relief currently forming a drowned barrier-island complex in the embayment.

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