## 5 Results
### End-Member Modeling Analysis  
The final end-members model accounts for 66% of the variance among different classes and 81% of the variance among samples (Figure 12). It identifies five dominant end-members (EMs) with peak modes--at 17 \(\upmu\)m (medium silt), 61 \(\upmu\)m (very coarse silt), 93 \(\upmu\)m (very fine sand), 100 \(\upmu\)m (very fine sand), and 130 \(\upmu\)m (fine sand). Each EM also includes minor modes. The explained variance for the five EMs is distributed as follows: EM1 (22%), EM2 (20%), EM3 (31%), EM4 (22%), and EM5 (5%). In the core CHA01, EM1 and EM2 dominate, accounting for 42% of the total variance. These end-members represent medium-to-very-coarse silts. EM3 to EM5 contribute to the remaining 58% of the total variance and correspond to very-fine-to-fine sands (Figure 12). Further division of the core reveals four major units (Figure 5).  
U1 (900-869 cm) exhibits a patchy distribution of EM abundances. However, EM1 and EM3 dominate the upper part of the unit, while EM4 and EM5 (the coarser end-members) have higher contributions in the lower part.  
U2 (868-488 cm) mainly consists of a combination of EM1, EM2, and EM3. The proportion of EM1 increases from the base to the top, while the contributions of EM2 and EM3 decrease. EM5 has a minor contribution, but it indicates the discrete recording of high-energy events (i.e., fine sand layers). Based on the relative proportions of EM1, EM2, and EM3, U2 can be further divided into three sub-units. U2a (868-744 cm) shows a significant contribution from EM2 and EM3, while the contribution from EM1 is negligible (less than 10%). In U2b (743-594 cm), the contributions of EM2 and EM3 remain dominant, but there is a slightly higher contribution of EM1, ranging from 50% to 60%. In U2c (593-488 cm), the contribution of EM1 remains high (more than 70%), while the contributions of EM2 and EM3 decrease compared to those of the two previous sub-units.  
U3 (487-189 cm) predominantly consists of a mixture of EM3 and EM4 (Figure 5). The abundance of EM4 decreases from the bottom to the top of the unit, while the contribution of EM3 increases. EM1, EM2, and EM5 remain minor components. Based on these observations, U3 can be divided into three sub-units. The upper sub-unit (487-406 cm) is dominated by EM4. The middle sub-unit (405-290 cm) exhibits a high contribution of EM3, while the contribution of EM2 is lower compared to U3a. The lower part (289-189 cm) is predominantly composed of EM3. Both U3b and U3c show prominent peaks of EM1, which account for 15-25% of the composition but are distributed unevenly within the two sub-units.  
Figure 11: CM image of the alluvial plain deposits of the Charente River.  
U4 (188-0 cm) is composed of a mixture of EM2, EM3, and EM4. The contribution of EMS is negligible. U4 can be subdivided into three sub-units (Figure 5). U4a (188-142 cm) exhibits a high contribution of EM2 and a low contribution of EM3 and EM4. In U4b (141-50 cm), EM3 dominates with a contribution of approximately 50-60%, while EM2 contributes between 40% and 50%. The abundance of EM4 is very low--less than 10%. Finally, the top sub-unit (U4c, 49-0 cm) shows a significantly high contribution of EM2. EM4 and EM5 are minor components, accounting for less than 20%, while EM3 is absent.