THE RECENT PALAEOLIMNOLOGY OF RED LAKE (ROMANIA); ASSESSING CHANGING SEDIMENT SOURCES FOR ENVIRONMENTAL MANAGEMENT

S.M. Hutchinson, University of Salford, Salford, UK
A. Frantiuc, A. Haliuc, M. Mindrescu, University of Suceava, Romania.
Gh. Romanescu, University of Iasi, Romania

Red Lake is probably one of the best known lakes to have been formed by land sliding in the Eastern Carpathian Mountains in north eastern Romania (Romanescu et al. 2010). It is also a popular tourist destination so that the lake has multiple user groups with an interest in the site’s effective environmental management. The lake was created following heavy rainfall in 1837 when a landslide blocked the Bicaz Brook (Bojoi, 1968; Pisota & Nastase 1957).  The lake has two main limbs running approximately north-south (1.0 km in length) and east-west (0.4 km in length) The average depth of the lake is 5.4 m (max. depth 9.6 m) with a surface area of 11.6 ha (Begy et al. 2009). Many aspects of the site have been investigated e.g. Pandi & Buzila (2004). This study presents an examination of the characteristics of recent sediment cores taken across the bed of the lake in the summer of 2011.
Four gravity cores deployed from a small inflatable boat were taken at locations (logged by GPS) along both the two main limbs of the lake. Sectioned at 2 cm intervals dried sediment samples have been characterised via XRF analysis (Niton XL3t 900), mineral magnetic measurements (Bartington Instruments Ltd MS2 System, Molspin Ltd Pulse Magnetiser and Minispin Fluxgate Magnetometer), the determination of the total organic and carbonate content (LOI) and sediment particle size distribution (Horiba Partica LA-950V2).
The mineral magnetic and geochemical characteristics of the site allow variations in the sediment sources contributing to the lake to be assessed. The sediments of the two main limbs of this infilling water body have differing characteristics as do basal and near surface sediment. These characteristics, together with the organic content and particle size distribution of the sediments, inform the sedimentation history of this reputedly rapidly in-filling lake. The key core appears to record a full sequence of siltation following the creation of the lake basin. Furthermore, an apparent change in sediment provenance can be observed when the rate of sedimentation has been identified as accelerating due to upstream forest clearance post 1989 (e.g. Begy et al. 2009). These insights provide guidance for future water policy decision making, catchment and channel management for the longevity and efficient environmental management of this important water body. This study also suggests the optimum location for further, chronologically controlled sediment-based studies.

Keywords: sediment provenance, environmental management and policy, sediment-based investigation, landslide-formed lake