Lake Neusiedl Area: A Particular Lakescape at the Boundary Between Alps and Pannonian Basin

Nanoscale Pathway of Modern Dolomite Formation in a Shallow, Alkaline Lake

“…To gain further insight into nanoscale growth pathways of dolomite in modern environments, we investigated the structure and compositional domains at high resolution in single carbonate crystals in sediments cored at the bottom of a shallow (average water depth ca. 1 m), episodically evaporative, and slightly alkaline lake located in the Pannonian Basin between Austria and Hungary (Lake Neusiedl or Fertő; Figure S1; see Draganits et al for a detailed review on the lake system). The lake sediments mostly consist of fine-grained Mg-calcite and protodolomite (e.g., Schroll and Wieden; Müller et al; Löffler et al). − In general, the lake water is supersaturated with respect to several Mg/Ca-carbonate minerals due to its relatively high pH (>8.5) and high Mg/Ca ratio (>0.5 mmol/l Ca 2+ and >4 mmol/l Mg 2+ ; Fussmann et al), but salinity, pH, and Mg/Ca ratio strongly vary between the seasons (Blohm) .…”

“…To gain further insight into nanoscale growth pathways of dolomite in modern environments, we investigated the structure and compositional domains at high resolution in single carbonate crystals in sediments cored at the bottom of a shallow (average water depth ca. 1 m), episodically evaporative, and slightly alkaline lake located in the Pannonian Basin between Austria and Hungary (Lake Neusiedl or Ferto; Figure S1; see Draganits et al 35 for a detailed review on the 36−38 In general, the lake water is supersaturated with respect to several Mg/Ca-carbonate minerals due to its relatively high pH (>8.5) and high Mg/ Ca ratio (>0.5 mmol/l Ca 2+ and >4 mmol/l Mg 2+ ; Fussmann et al), 34 but salinity, pH, and Mg/Ca ratio strongly vary between the seasons (Blohm). 39 Near the sediment/water interface, pH is lower than in the water column above and the water is undersaturated with respect to low-Mg calcite, while remaining supersaturated with respect to the other carbonate phases, in particular protodolomite and dolomite (Fussmann et al).…”

Radiocarbon ages of microcrystalline authigenic carbonate in Lake Neusiedl (Austria) suggest millennial‐scale growth of Mg‐calcite and protodolomite

“…Three samples were investigated in this study; two were taken from sediments in the modern lake (samples KR7-D and SEE8-1) and one in older lake sediments exposed in a construction pit at the northern shore, near the village of Jois (sample ED05/JOIS/3; Draganits et al, 2022). At the two sites in the lake, KR7 (N 47°48 0 53.68 00 /E 016°42 0 19.42 00 ) and SEE8 (N 47°52 0 27.97 00 /E 016°44 0 01.61 00 ; Fig.…”

“…; at Trieste, Adriatic Sea) and the water body covers 321 km 2 (143 km 2 open water, 178 km 2 reed area; Bácsatyai et al ., 1997). Despite its large surface area, its water depth is only about 1.4 m on average (Heine et al ., 2014) with a maximum depth of 1.8 m. The lake area and the wetlands to the east, including diverse saline ponds (‘Seewinkel’), represent a highly dynamic system where the present‐day extent of the water body and tributaries is very different from past conditions (Draganits et al ., 2022). At present, the catchment comprises 1120 km 2 (Herzig, 2014) and only the river Wulka and a few very small tributaries in the west and south of the lake provide surface water inflow (e.g.…”

“…Calcium-magnesium carbonates often form in evaporative marine and lacustrine environments, where they exhibit a diverse mineralogy, including hydrous, amorphous to poorly crystalline carbonates, aragonite, calcite and dolomite (e.g. Eugster & Hardie, 1978;Warren, 1990Warren, , 2010Teal et al, 2000;Gierlowski-Kordesch, 2010, and references therein). Calcite often shows a variable Mgcontent, ranging from low-Mg calcite (LMC) to high-Mg calcite (HMC) and 'very-high-Mg calcite' (Lumsden & Chimahusky, 1980).…”