Thermochronology of hydrothermal alteration zones in the Kii Peninsula, southwest Japan: an attempt for detecting the thermal anomalies and implications to the regional exhumation history

Earth, Planets and Space

Table 3 Summary of zircon U–Pb data for sedimentary rocks and alteration zones

Sample code	All grains	YC2σ		YSG
Sample code	All grains	n	Age ± 1σ [Ma]	Age ± 1σ [Ma]
HJG1-F	30	12	73.9 ± 2.7	68.6 ± 1.9
HJG1-0–5 cm	30	7	70.0 ± 2.9	65.5 ± 2.0
HJG1-5–10 cm	30	4	65.9 ± 4.3	59.6 ± 2.7
HJG1-0 m	28	6	72.0 ± 5.1	66.7 ± 2.1
HJG1-1 m	30	8	71.1 ± 3.7	64.3 ± 2.5
HJG1-3 m	30	10	74.7 ± 4.1	69.1 ± 2.6
HJG1-10 m	30	15	71.9 ± 3.7	65.9 ± 3.6
HJG1-20 m	30	4	66.4 ± 6.5	57.3 ± 3.2
HJG2-F	30	2	63.0 ± 4.2	60.3 ± 1.8
HJG2-0–5 cm	30	13	74.2 ± 2.0	70.4 ± 2.2
HJG2-5–10 cm	30	10	74.6 ± 3.6	69.0 ± 2.6
HJG2-0 m	30	5	63.5 ± 4.4	55.2 ± 3.8
HJG2-1 m	30	14	73.2 ± 5.0	67.0 ± 4.5
HJG2-3 m	30	7	71.2 ± 4.8	64.1 ± 2.7
HJG2-10 m	30	4	63.7 ± 5.1	57.8 ± 2.4
HJG4-0 m	30	4	69.1 ± 5.3	62.0 ± 2.8
HJG4-1 m	30	4	69.5 ± 5.4	61.7 ± 2.5
HJG4-3 m	30	5	71.2 ± 3.0	66.6 ± 2.6
HJG4-10 m	30	1	59.2 ± N/A	59.2 ± 4.0

YC2σ: youngest grain cluster at 2σ; YSG: youngest single grain (Dickinson and Gehrels 2009; Coutts et al. 2019). Bold font indicates the maximum depositional age adopted. YC2σ is expected to be calculated from three or more grains; therefore, the estimates for HJG2-F and HJG4-10 m were not adopted as the maximum depositional age (Additional file 3: Fig. S2)