## 5 Discussion
From our study, we infer a relative decrease in magnetite concentration in respect to the high coercivity components in TD7 based on the S-ratio and bulk susceptibility profile (Figure 6a). Based on the conventional wisdom, we could tentatively correlate level TD7 to a warm time interval. The results of the TD8 unit suggest a distinct magnetite content and a constant high coercivity concentration; moreover, the presence of a stalagmitic crust on the top suggests a warm to temperate climate [17], and it was tentatively attributed to MIS13 (Marine Isotope Stage; [58]). The higher concentration of magnetite and the slight decrease of high coercivity content found in TD8.9 unit can be considered a passage from a humid and cold period. Higher up in the section, the middle-upper part of TD9 unit stands out both because of its visible stratigraphic characteristics (Figure 12) and for its distinctive rockmagnetic properties as shown in this study. As far as stratigraphy, the upper part of TD9 constitutes a rather thick unit of finer grain sediments, in contrast to the underlying and overlying units made up by coarse breccias. Additionally, the lamination and the colour changes configure this level as a distinctive interval in the whole section. Resuming the results, the middle-upper part of TD9 unit presents the following: low magnetic susceptibility (Figure 6a) compared to the entire sequence; a decrease of the superparamagnetic contribution (as evidenced by frequency-dependent susceptibility in Figure 6c); and especially an abundance of hard ferromagnetic minerals (goethite and hematite) as shown by lower values of S-ratio (Figure 8a) and by IRM progressive acquisition curve (light blue in Figure 3), far from saturation. Moreover, such level presents the smallest magnetic particles of the entire profile, as detected by maximum values of IRM\({}_{\text{1T}}\)/x\({}_{\text{lf}}\) (Figure 8c) and by the King plot (Figure 11). Previous studies also conducted also cave environments [59; 60; 61] reveal that the increase in susceptibility, correlated to the presence of magnetite, could be due to warm climatic periods, possibly for the pedogenesis processes mentioned earlier. Therefore, the decrease of susceptibility observed in this middle-upper part of the TD9 unit could suggest a priori, the opposite, a cold interval inhibiting the formation and/or deposition of magnetite. An additional prominent feature distinguishes the TD9 unit, namely the presence of goethite as inferred from the coercivity study that shows extreme values of B\({}_{1/2}\) (more than 3000 mT, as summarized in Table 3). The presence of goethite could cover up the  
Figure 12: Detailed view of the TD9 unit and contact with TD10 (overlying breccias), showing the characteristic alternating colours and parallel lamination. SP particles present in this level and could indicate a rather humid environment for the conditions necessary to form this mineral. The age dating results could help our proposed environmental reconstruction. There exist a number of age data for the upper levels of the Gran Dolina cave. In particular, a first study [13] using ESR and U-series on teeth assigns to TD8 a mean age of 602 \(\pm\) 52 ka and 372 \(\pm\) 33 ka for TD10. For this last, the authors suggested a rapid sedimentation rate and a possible correlation to MIS11. Based on thermoluminescence (TL) and infrared-stimulated-luminescence (IRSL) methods [28], subsequent ages were obtained: 960 \(\pm\) 120 ka for TD7; 820 \(\pm\) 140 ka for TD8; 480 \(\pm\) 130 ka for TD9; and a time interval between 430 \(\pm\) 59 and 240 \(\pm\) 44 ka for TD10, although, later on, [62] discussed the validity of such TL results and furnished new ages based on thermally transferred optically stimulated-luminescence (TT-OSL), namely 856 \(\pm\) 75 ka for TD6, which is in excellent agreement with new paleomagnetic data [14]. In [63], a new age of 418 \(\pm\) 113 ka was added for the TD9 unit. Finally, ESR data on optically bleached quartz grains extracted from sediments (ESR-OB, [29]) furnished new values.