(U–Th)/He thermochronometric mapping across the northeast Japan Arc: towards understanding mountain building in an island-arc setting

Earth, Planets and Space

Table 3 Summary of all samples’ parameters

Sample (“A02-”)	Tectonic units	Geology	E-lon. (°)	N-lat. (°)	Elevation (m asl.)	Weighted mean age ± 95% CI (Ma)		T_c of AHe (°C)	Grad.^a (°C/km)	Grad.^b (°C/km)	dD/dt^a (mm/year)	dD/dt^b (mm/year)
Sample (“A02-”)	Tectonic units	Geology	E-lon. (°)	N-lat. (°)	Elevation (m asl.)	AHe	ZHe	T_c of AHe (°C)	Grad.^a (°C/km)	Grad.^b (°C/km)	dD/dt^a (mm/year)	dD/dt^b (mm/year)
FST03	Back-arc	CrGr	139.95400	40.45519	48	3.2 ± 0.2	21.3 ± 3.3	68.8 ± 10.3	50 ± 10	45 ± 5	0.37 ± 0.11	0.41 ± 0.10
FST04	Back-arc	CrGr	140.34781	39.74967	167	N/A	83.9 ± 8.3	–	–	–	–	–
FST05	Back-arc	CrGr	140.54808	39.73444	196	4.9 ± 0.8	9.9 ± 1.0	68.0 ± 12.4	50 ± 10	55 ± 5	0.24 ± 0.08	0.21 ± 0.06
FST06	OBR	CrGr	140.83033	39.59797	487	6.2 ± 0.6	N/A	64.2 ± 2.1	50 ± 10	55 ± 5	0.18 ± 0.04	0.16 ± 0.02
FST07	Fore-arc	CrGr	141.25269	39.45172	321	88.6 ± 8.8	–	50.7 ± 10.7	30 ± 10	45 ± 5	0.02 ± 0.01	0.01 ± 0.00
FST08	Fore-arc	CrGr	141.69792	39.35217	507	43.7 ± 4.3	–	54.5 ± 10.3	30 ± 10	35 ± 5	0.03 ± 0.01	0.03 ± 0.01
FST09	Fore-arc	CrGr	141.94769	39.40333	131	45.0 ± 4.5	–	56.4 ± 20.0	30 ± 10	35 ± 5	0.03 ± 0.02	0.03 ± 0.01
FST10	OBR	CrGr	140.89867	39.22128	595	0.9 ± 0.1	N/A	78.3 ± 8.6	50 ± 10	55 ± 5	1.44 ± 0.43	1.31 ± 0.32
FST11	OBR	CrGr	140.85497	39.47828	411	5.1 ± 0.5	14.7 ± 2.3	68.8 ± 1.9	50 ± 10	45 ± 5	0.23 ± 0.05	0.26 ± 0.04
FST12	OBR	CrGr	140.49842	39.09986	268	3.7 ± 0.4	17.2 ± 2.7	70.2 ± 6.5	50 ± 10	65 ± 5	0.33 ± 0.08	0.25 ± 0.04

E-lon. and N-lat. indicate the east longitude and the north latitude of every sample. Weighted mean ages are from Tables 2 and 3, calculated from single grain ages of each sample with IsoplotR (Vermeesch 2018). Ages in parentheses are average ages indicating that weighted mean ages were not adopted because of less reproducibility. T_c denotes the closure temperature of the AHe system based on the Dodson (1973)’s method. Grad.: Geothermal gradients
^aUsing the database of Tanaka et al. (2004)
^bUsing the layer data of GSJ (2009). dD/dt shows the mean denudation rates since the apparent AHe ages. CrGr Cretaceous granite. OBR Ou Backbone Range. N/A denotes a weighted mean age was not adopted because of a poor reproducibility