**4.1 Lithology of the sediment–water interface core BAF-3B**

The lithology of the sediment–water interface core "BAF-3B" from the northeastern part of the lake predominantly contains fine-grained sediments, with averages of 18% sand, 34% silt, and 40% clay. The uppermost 0.15 m of the core contains gray and greenish-gray homogeneous sandy silty clays. Sediments from the lowermost parts were characterized by light to dark gray laminated sandy silty clay layers, enriched with small bivalve shell fragments [8].

### **4.2 Lithology of the core BAF37**

The sedimentary section of core BAF37 consists of five main lithostratigraphic units (**Figure 2**). The uppermost 1.2 m of the sediment section is a greenish-olive gray homogeneous sandy, clayey silt. A 15 cm thick, black, banded, homogeneous clayey silt layer follows this unit downward. The third unit (UII:1.35–1.90 m) is a light bluish gray to yellow, laminated clayey silt. The following unit (UIV:1.90–3.56 m) consists of intercalations of bluish gray homogeneous sandy silty clay and olive-green clayey silt and clay. The lowermost unit below 3.56 m (UV) has variable lithological layers changing from homogeneous to laminated and from sands to clays, with beige and light gray to black colors. In detailed lithological observations including the grain size composition data (averages of 4% sand, 68% silt, and 28% clay), this unit is composed of predominantly fine-grained sediments [8, 9].

#### **4.3 Lithology of the borehole (swamp) section (BS)**

The swamp section is divided into four main lithological units. The uppermost 2.7 m of the sequence (Us I) is mainly characterized by brown sandy clay (**Figure 3**). Unit "Us I" includes a topsoil formation and is rich in plant residues in the uppermost part. Lowermost parts include a well-sorted sand layer and partly oxidized clay layers. The second unit (Us II; 2.7–7.2 m depth) contains laminated,

partly organic-rich or oxidized clay layers, enriched in gastropod shells and shell fragments. The third unit (Us III; 7.2–8.7 m) is characterized mainly by a gray to brown, homogeneous clay, which is partly interrupted by either thin laminated clay layers or sandy, silty clay layers. It is enriched in Vermetidae or bivalve shell fragments. The lower parts of this unit (8.9–10.4 m) consist predominantly of homogeneous sand layers, containing abundant bivalve shells. The lowermost unit (Us IV; 10.4–11.9 m) is a gray, well-sorted homogeneous sand, with the abundant

*"Geo-archives of a Coastal Lacustrine Eco-system": Lake Bafa (Mediterranean Sea)*

*DOI: http://dx.doi.org/10.5772/intechopen.85589*

A total of five radiocarbon ages measured on mollusk shells were considered for the chronology (**Table 1**) [8, 9]. Three *Cerastoderma glaucum sp. shells* from three different depths in core BAF-37 were radiocarbon dated. A single valve of *Cerastoderma glaucum sp. from* 1.98 m depth provided a conventional age of 1570 (+/ 30) BP. Additional two AMS radiocarbon dates from single valves of

*Cerastoderma glaucum sp. from* 3.38 m and 3.83 m core depths yielded 2250 (+/30) and 2330 (+/30) year BP. The 14C ages show a regular increase with depth. Furthermore, these age estimates indicate a low sedimentation rate during the deposition of lake sediments (0.24 cm/year); this rate is in agreement with the results of previous measurements [22]. Two AMS radiocarbon dates from single *Cerastoderma glaucum sp. shells* collected at the 4.81 m and 7.53 m depths of swamp section (BS) yielded conventional dates of 2780 (+/ 30) and 3070 (+/ 30) BP, respectively. According to the radiocarbon dates, together with visual observations, the swamp and lake sequences represent continuous sedimentary records of the last

rock fragments and bivalve shells.

*Lithostratigraphic description of the swamp section (drill core BS).*

4.5 and 2.5 cal. ka years, respectively.

**33**

**5. Chrono-stratigraphy**

**Figure 3.**

**Figure 2.** *Lithostratigraphic description of core BAF37.*

*"Geo-archives of a Coastal Lacustrine Eco-system": Lake Bafa (Mediterranean Sea) DOI: http://dx.doi.org/10.5772/intechopen.85589*

**Figure 3.** *Lithostratigraphic description of the swamp section (drill core BS).*

partly organic-rich or oxidized clay layers, enriched in gastropod shells and shell fragments. The third unit (Us III; 7.2–8.7 m) is characterized mainly by a gray to brown, homogeneous clay, which is partly interrupted by either thin laminated clay layers or sandy, silty clay layers. It is enriched in Vermetidae or bivalve shell fragments. The lower parts of this unit (8.9–10.4 m) consist predominantly of homogeneous sand layers, containing abundant bivalve shells. The lowermost unit (Us IV; 10.4–11.9 m) is a gray, well-sorted homogeneous sand, with the abundant rock fragments and bivalve shells.
