The foraminiferal record in the Holocene evolution of the Mecklenburg Bay (south-western Baltic Sea)

Robert Kostecki; Teresa Radziejewska

doi:10.2478/oandhs-2021-0016

Figures & Tables

Location of the Core 317980-3 collection site in the Mecklenburg Bay (south-western Baltic Sea)

Decalcified tests of Ammonia foraminifera from Core 317980-3

Distribution of dominant foraminiferal assemblages in Core 317980-3 [age–depth model developed from radiocarbon dates after Kostecki et al. (2015) using CALIB 8.1 radiocarbon calibration programme (Stuiver and Reimer 1993) as well as Marine20 and IntCal20 curves (Heaton et al. 2020; Reimer et al. 2020)]; C/A ratio – calcareous to agglutinated foraminifera ratio

CCA ordination plot for the analysis of foraminifera and biogeochemical variables in Core 317980-3; LOI – loss on ignition; Mean grain – mean grain size; Si ter – terrigenous silica; Mg – magnesium content; Ca – calcium content; Si biog – biogenic silica; geochemical data description published in Kostecki et al. (2015)

Results of Canonical Correlation Analysis

	Dimensions
	1	2	3	4
Cumulative percentage of variance explained	0.82	0.92	0.96	0.99
Environmental parameters
Si ter	−0.28	0.02	−0.10	0.87
Si biog	0.56	−0.66	−0.20	−0.41
Mg	0.58	−0.01	0.01	−0.56
LOI	−0.30	0.21	−0.05	−0.91
Ca	0.23	0.25	−0.21	0.05
Mean grain size	0.20	0.87	−0.08	0.34
Foraminifera taxa
Ammonia group	0.77	−0.61	−0.18	−0.02
Eggerelloides scaber	−0.76	−0.55	−0.32	−0.06
Trochamminacea	0.55	0.07	−0.80	0.25
Reophax sp.	0.33	0.05	−0.65	−0.69

Foraminifera-based stratigraphy of Core 317980-3

Foraminifera – based unit (F) and age (cal yrs BP)	Core layer (cm)	Assemblage characteristics	Sediment characteristics	Notes and comments
F1+10 700–c. 8100	620–540	No foraminifera	Admixture of fine sand; sulphide micronodules in the deepest layer; abundant fine and coarse plant remains (including seeds and characean oogonia), freshwater mollusc shell fragments	Abundant cladoceran fauna (600–540 cm); occasional shells of limnic ostracods
F2c. 8100–c. 6900	540–470	Foraminifera present; abundance fluctuates, but gradually increases to peak at 475–480 cm, and to decline thereafter; almost 100% domination of the Ammonia group, with a slight admixture of arenaceous forms; C/A ratio strongly in favour of calcareous forms	The lowest layer still with cladoceran fragments; mud with admixture of fine sand; abundant plant remains	Occasional hydrobiid snail shell fragments
F3c. 6900–c. 6300	470–410	Maximum abundance; highest taxon richness; domination of the Ammonia group (occasionally not decalcified), but contribution of arenaceous forms fairly well visible; C/A ratio strongly in favour of calcareous forms	Mud; some plant remains; admixture of fine sand	Occasional brackish-water ostracods and mollusc shell fragments
F4c. 6300–c. 3000	410–175	Abrupt decline in abundance; C/A ratio still in favour of calcareous forms, but agglutinated forms gaining in importance	Mud; occasionally abundant plant remains; admixture of fine sand	Fragments of mollusc shells; occasional valves of fresh- and brackish-water ostracods as well as cladoceran ephippia and carapace fragments
F5c. 3000–present	175–0	Fluctuating, generally low abundance (except for one layer with an exceptionally high abundance peak); domination of Eggerelloides scaber; C/A ratio very strongly in favour of agglutinated forms	Plant remains; admixture of fine sand; occasional sulphide micronodules	Mollusc shell fragments (e.g. Cardium), occasionally abundant; valves of fresh- and brackish-water ostracods

The foraminiferal record in the Holocene evolution of the Mecklenburg Bay (south-western Baltic Sea)

Figures & Tables

Figure 1

Figure 2

Figure 3

Figure 4

Results of Canonical Correlation Analysis

Foraminifera-based stratigraphy of Core 317980-3

Paradigm

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