Table 1.

40Ar/39Ar isotopic results of incremental heating experiments for hornblende separates from representative andesitic sample in the Shangcheng area, Northern Huaiyang Belt

T (°C)(40Ar/39Ar)m(36Ar/39Ar)m(37Ar/39Ar)m(38Ar/39Ar)m39Ark (10−12 mol)(40Ar*/39Ark) (±1σ)39Ark (%)Apparent age (t ± 1σ Ma)
03XY-69, hornblende, from Jingangtai Fm. in Shangcheng area
5009.3290.01400.55020.00120.1815.236 ± 0.2601.470125.5 ± 6.1
8007.6600.00870.61810.00150.3565.141 ± 0.1302.890123.3 ± 3.1
9007.6780.00730.65510.00130.4665.573 ± 0.1153.780133.3 ± 2.8
9507.3160.00640.41570.00080.7695.455 ± 0.0876.240130.6 ± 2.1
10007.0480.00570.19700.00041.9925.368 ± 0.05716.16128.6 ± 1.4
10506.9150.00550.20960.00042.3725.312 ± 0.04319.24127.3 ± 1.0
11006.8250.00510.25870.00052.1515.328 ± 0.04917.45127.6 ± 1.2
11507.1180.00630.27710.00052.0135.281 ± 0.04716.33126.6 ± 1.1
12008.0710.00910.37730.00091.2605.416 ± 0.07010.22129.7 ± 1.8
12508.4930.01060.90160.00310.3995.445 ± 0.1403.240130.4 ± 3.3
13007.4770.00781.08670.00320.2615.282 ± 0.0602.120149.5 ± 1.8
13507.7280.00880.79610.00680.1065.188 ± 0.2500.860146.9 ± 7.0

λ = 5.543 × 10−10, J = 0.0137613, weight = 0.075 g, plateau age = 128.8 ± 1.2 Ma.