## 4 Results and Interpretation
### AFT Age Data
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Samples/** \\ **Mineral** \\ \end{tabular} } & \multirow{2}{*}{**N**} & \multicolumn{2}{c}{**Spontaneous**} & \multicolumn{2}{c}{**Induced**} & \multicolumn{2}{c}{**Dosimeter**} & \multirow{2}{*}{**P(\(\chi^{2}\))**} & \multicolumn{2}{c}{**Central**} & \multicolumn{2}{c}{**Pooled**} & \multicolumn{2}{c}{**Mean Track**} & \multicolumn{1}{c}{**Mean**} \\  & & **p\({}_{\text{s}}\) (105\({}^{\circ}\)/cm\({}^{2}\))** & \(\rho_{\text{s}}\) (10\({}^{\circ}\)/cm\({}^{2}\))** & \(\rho_{\text{d}}\) (10\({}^{\circ}\)/cm\({}^{2}\))** & **(\%)** & **Age (Ma)** & **Age (Ma)** & **Length (\(\mu\)m)** & **Dpar** \\  & & **(Ns)** & **(Ni)** & **(Nd)** & **(\%)** & **(\%)** & **(\(\pm\) 1\(\sigma\))** & **(\(\pm\) 1\(\sigma\))** & **(N)** & **(\(\mu\)m)** \\ \hline LS–82–Ap & 35 & 3.207 & 11.291 & 9.107 & 69.9 & 52 \(\pm\) 3 & 53 \(\pm\) 3 & 12.8 \(\pm\) 1.8 & 1.37 \\  & & (1491) & (5250) & (6788) & & & & (102) & 1.37 \\ LS–86–Ap & 35 & 2.275 & 7.558 & 9.524 & & & & 12.2 \(\pm\) 1.7 & \\  & & (1773) & (5889) & (6788) & & & & & (107) & 1.30 \\ LS–94–Ap & 37 & 6.182 & 13.565 & 9.93 & & & & & 12.2 \(\pm\) 1.5 & \\  & & (1808) & (3967) & (6788) & & & & & (101) & 1.25 \\ LS–95–Ap & 35 & 8.222 & 17.848 & 10.36 & & & & & 12.7 \(\pm\) 1.5 & \\  & & (1774) & (3851) & (6788) & & & & & (108) & 1.24 \\ LS–96–Ap & 35 & 15.856 & 52.177 & 10.714 & & & & & 12.2 \(\pm\) 1.6 & \\  & & (4266) & (14,038) & (6788) & & & & & (112) & 1.32 \\ LS–97–Ap & 35 & 8.585 & 12.343 & 8.573 & & & & & 11.8 \(\pm\) 1.8 & \\  & & (2049) & (2946) & (6788) & & & & & (112) & 1.49 \\  & & 6.371 & 11.648 & 8.923 & & & & & 11.9 \(\pm\) 1.5 & \\ LS–98–Ap & 35 & (1719) & (3143) & (6788) & 0.7 & 99 \(\pm\) 6 & 99 \(\pm\) 5 & 11.0 & 1.28 \\ LS–94–Zr & 36 & 146.74 & 61.537 & 12.792 & & & & & (110) & 1.28 \\  & & (7645) & (3206) & (8055) & & & & & \\ LS–95–Zr & 24 & 177.869 & 66.518 & 13.282 & & & & & \\  & & (4511) & (1687) & (8055) & & & & & \\ LS–96–Zr & 20 & 169.687 & 65.0 & 13.773 & & & & & \\  & & (2869) & (1099) & (8055) & & 171 \(\pm\) 13 & 161 \(\pm\) 8 & - & - \\ LS–97–Zr & 35 & 127.275 & 56.667 & 14.263 & & & & & \\  & & (5067) & (2256) & (8055) & 0 & 143 \(\pm\) 9 & 144 \(\pm\) 6 & - & - \\ LS–98–Zr & 34 & 176.761 & 71.525 & 14.875 & & & & & \\  & & (10,130) & (4099) & (8055) & 0 & 166 \(\pm\) 8 & 165 \(\pm\) 6 & - & - \\ LS–99–Zr & 35 & 156.345 & 66.188 & 15.488 & & & & & \\  & & (4918) & (2082) & (8055) & 0 & 162 \(\pm\) 12 & 164 \(\pm\) 7 & - & - \\ \hline \hline \end{tabular} Note: N = total number of analyzed grains. \(\rho\) represents track density. P(\(\chi^{2}\)) is chi-square probability. “-” is not data. Apatite ages calculated with \(\zeta\) (zeta) = 410 \(\pm\) 17.6 (yr cm\({}^{2}\)/tr) and zircon ages calculated with \(\zeta\) (zeta) = 90.9 \(\pm\) 2.8 (yr cm\({}^{2}\)/tr).  
\end{table} 
Table 2: Fission-track data of apatite and zircon from the central and south HTB. Figure 4: Histogram of the AFT age and ZFT age (N = number of analyzed grains in the correspondent age intervals). (**A**) It is shown that 4 AFT age groups of 147 Ma, 120–109 Ma, 92–77 Ma, and 65–50 Ma. (**B**) It is shown that 5 ZFT age groups of 279 Ma, 222–213 Ma, 193–169 Ma, 151 Ma, and 130–110 Ma.