## 5 Results
### Textural Triangles  
Textural analysis, which involves determining the relative proportions of sand, silt, and clay, is a commonly used method to represent grain size data. However, there is no consensus regarding the boundaries between different grain size categories and sub-categories. To identify the most suitable classification scheme that maximizes the contrast between the samples, six textural classifications were tested on the 158 samples. The resulting membership in each class was encoded to assess the sensitivity of each system and enable a comparison between them (Figure 5). The Folk scheme divides sand-silt-clay samples into 10 sub-categories (Figure 6). For the samples from core CHA01, only seven sub-categories are present, and three of them include only a limited number of samples (one to three individuals). Among the remaining four categories, sandy silt and silts dominate, accounting for 55% and 25%, respectively (Figure 7), while mud and sandy mud are poorly represented (less than 11% and 6%, respectively). This classification scheme was not used to propose a division of the core. The European soil map (HYPRES) proposes a classification system with only five sub-categories (Figure 6). All of them are represented in core CHA01, but the extreme sub-categories (very fine and coarse) have only one individual each and are of limited usefulness. The remaining three sub-categories are medium-fine (49%), medium (41%), and fine (9%) (Figure 7). According to the HYPRES sub-categories, the core can be divided into four main units (Figure 5). U1 (900-869 cm) appears highly heterogeneous, encompassing a mixture of all sub-categories. Most of U2 (868-488 cm) is predominantly composed of an alternation between sub-categories 3 and 4 (U2a, 868-594 cm), except for its upper section, which displays a combination of sub-categories 2 and 4 (U2b, 593-488 cm). U3 (487-189 cm) exhibits a composition similar to U2a, except in its base. Consequently, U3 can be further divided into U3a (487-189 cm) and U3b (405-189 cm). U4 represents the most homogeneous unit and is dominated by sub-category 3. However, the presence of sub-category 2 in its middle portion (U4b, 136-90 cm) leads to its subdivision into three sub-units. Additionally, the ISS texture triangle provides a 12-sub-category classification system. Among these, only seven are represented in core CHA01, with the top three accounting for 96% of the samples, namely silty clay, silty clay loam, and silt loam (Figure 7). Figure 6: Trigons showing the samples of the core CHA01 classified using several texture classification schemes: (**a**) Gradistat, (**b**) HYPRES, (**c**) ISSS, (**d**) USDA TT, (**e**) UK SSEW, and (**f**) AISNE. According to the ISSS classification scheme, the core can also be subdivided into four main units (Figure 5). U1 (900-869 cm) exhibits some fluctuations in sample classification. U2 (868-488 cm) can be divided into three sub-units. The upper sub-unit (868-761 cm) predominantly consists of silty clay loam samples, the middle sub-unit (760-682 cm) varies between containing silty clay and silty clay loam samples, and the lower sub-unit (681-488 cm) primarily comprises silty clay samples. U3 (487-189 cm) can also be divided into three sub-units. U3 (487-394 cm) is composed of silt loam samples, U3b (393-290 cm) exhibits variations between silty clay, silty clay loam, and silt loam samples, and U3c (289-189 cm) consists predominantly of silty clay loam. U4 (188-0 cm) represents a globally homogeneous unit dominated by sub-category 7. However, the presence of sub-category 4 in its middle section (U4b, 141-60 cm) implies in its division into three sub-units. The USDA Texture Triangle classifies sediments into 12 sub-categories. However, on core CHA01, only seven of these sub-categories are represented, with the top two accounting for over 93% of the samples. The predominant groups are silt loam (67%) and silty clay loam (26%), while silty clay represents a smaller proportion (less than 4%).