Age-depth relationship and accumulation rates in four sediment sequences from the Retezat Mts, South Carpathians (Romania)

Katalin Hubay, Mihály Molnár, Ildikó Orbán, M. Braun, T. Bíró, Eniko Magyari

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

This study summarizes the results of radiocarbon dating and age-depth modelling in four mountain lakes (Brazi, Gales, Bucura and Lia) in the Retezat Mountains. Altogether 69 AMS 14C measurements were performed on these deposits, mostly on terrestrial plant macrofossils. In several cases, plant macrofossils, aquatic animal remains (Cladoceran eggs) and bulk sediment were measured from the same depth allowing for the comparison of various sediment components in terms of their dating potential. Age-depth models were developed using both Bayesian modelling with the BACON and smooth spline curve fitting with the CLAM software. In this study Bayesian models are applied to identify outlier 14C dates, while smooth spline models are used to model sediment accumulation age-depth relations, as these are more likely to follow natural deposition time changes of lake sediments. Changes in sediment deposition times (DT) in relation to catchment size and climate are also studied.DT varied considerably in the late glacial (LG) part of the records. The sediment sequence characterised by high deposition rates during the late glacial (DT maximum around 100-110 years cm-1) was defined by small catchment size (Lake Brazi, 6 ha; surface area: 0.5 ha). In contrast, much slower LG sediment deposition in the southern slope lake characterised by large catchment area (Lake Lia, 171 ha, 20 years cm-1), principally reflecting strong erosion in these catchment areas at times when vegetation cover was scarce. Holocene was characterised again by variable DT values, but only Lake Gales showed extreme values: 62-110 years between 10,900 and 6050 cal yr BP, followed by much slower sediment deposition in the last 6000 years (av. 29 years cm-1). Generally, sediment deposition times were largely dependent on the stability and vegetation cover of the slope in the case of high altitude deep lakes, while lower altitude, shallow lakes showed slower sediment deposition time in the early and mid-Holocene, when summer insolation was higher than today. This reflects that in these shallow lakes in-lake organic production probably increased with summer insolation, which was a significant driver in the rate of deposition.

Original languageEnglish
JournalQuaternary International
DOIs
Publication statusAccepted/In press - 2016

Fingerprint

accumulation rate
sediment
lake
late glacial
insolation
vegetation cover
Holocene
catchment
mountain
summer
glacial deposit
accelerator mass spectrometry
radiocarbon dating
outlier
modeling
lacustrine deposit
surface area
egg
erosion
software

Keywords

  • AMS C dating
  • Carpathians
  • Glacial lake sediments
  • Holocene
  • Late glacial

ASJC Scopus subject areas

  • Earth-Surface Processes

Cite this

Age-depth relationship and accumulation rates in four sediment sequences from the Retezat Mts, South Carpathians (Romania). / Hubay, Katalin; Molnár, Mihály; Orbán, Ildikó; Braun, M.; Bíró, T.; Magyari, Eniko.

In: Quaternary International, 2016.

Research output: Contribution to journalArticle

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