Supplementary files for ``Late Cretaceous–Paleogene terrestrial sequence in the northern Kitakami Mountains, Northeast Japan: Depositional ages, clay mineral contents, and vitrinite reflectance.''

This includes supplementary files for the research article of "Late Cretaceous–Paleogene terrestrial sequence in the northern Kitakami Mountains, Northeast Japan: Depositional ages, clay mineral contents, and vitrinite reflectance."</p

Ascent of migmatites of a high-temperature metamorphic complex due to buoyancy beneath a volcanic arc: a mid-Cretaceous example from the eastern margin of Eurasia

<p>Mixtures of melt and residue in a high-<i>T</i> metamorphic complex have a lower density and viscosity than the surrounding host crust, and the mixtures should ascend due to buoyancy. The mixtures are recognized as migmatites in the high-<i>T</i> metamorphic complex. To confirm ascent of migmatites, we conducted numerical simulations of ascent of a model migmatite (buoyant viscous fluid). The numerical simulations show that the model migmatite could rise to shallow levels of a model crust so long as it is continuously produced at the bottom of the model crust. Otherwise it ceases to rise at depth due to loss of buoyancy by cooling. The numerical simulations also show that the model migmatite experiences vertical thinning during the ascent. The ascent mechanism proposed in this paper requires the continuous production of partially melted rocks at the base of the crust, which is provided by a continuous input of energy into the crust from the mantle. Given that high-<i>T</i> metamorphic complexes are associated with igneous activity beneath a volcanic arc, the igneous activity reflects the energy input into the lower crust from the mantle. A high-grade part (migmatites) of a high-<i>T</i> metamorphic complex in the Omuta district of northern Kyushu, southwest Japan, experienced thinning during ascent. Large amount of igneous rocks, such as plutonic and volcanic rocks, are also distributed in northern Kyushu. Zircon U–Pb ages of igneous rocks from northern Kyushu reveal that igneous activity continued from 115 to 93 Ma, and that peak igneous activity at 110–100 Ma was synchronous with the ascent of migmatites of the high-<i>T</i> metamorphic complex in northern Kyushu. Therefore, the numerical simulations may provide an appropriate model of the ascent of migmatites of the high-<i>T</i> metamorphic complex beneath a volcanic arc, at the eastern margin of Eurasia in the mid-Cretaceous.</p

LA-ICP-MS zircon fission-track (FT) data of three tuff and tuffaceous sandstone samples in Memanbetsu and adjacent areas, Hokkaido, Japan.

Appendix 1. LA-ICP-MS fission-track zircon data. A: ID No. 2089. B: ID No. 19091812-1. C: ID No. 19061601.  The sampling locations are as follows; ID No. 2089: 43°55'63.82"N, E144°1'25.14"E. ID No. 19091812-1: 43°43'39.86"N, 144°1'13.18"E. ID No. 19061601: 43°59'58.29"N, 144°13'23.27"E.    Appendix 1A [Foot Note]  *Particles excluded from dating **E.S.: External Surface Ns: Number of counted fission tracks  ρs: Spontaneous fission track density Nu-sp: Number of area-corrected 238U counts on unknown sample ρu-sp: Density of area-corrected 238U counts on unknown sample Nu-std : Total count of 238U on Uranium Standard sample ρu-std: Density of 238U counts on Uranium Standard sample P (χ2) : probability of obtaining the χ2 value for ν degrees of freedom (ν = number or crystals - 1)  Zeta value for fission track age calibration : 43.8 ± 2.0 (yr・cm-2) age: t = (1/λD)・ln [1+λD・ζ・(Ns /Nu-sp)・ρu-std ] error: σt = t×[1/ΣNs + 1/ΣNu-sp + 1/ ΣNu-std +(σζ/ζ)2]1/2  total decay constant of 238U: λD = 1.55125×10-10 yr-1 Appendix 1B [Foot Note]  *Particles excluded from dating **E.S.: External Surface Ns: Number of counted fission tracks  ρs: Spontaneous fission track density Nu-sp: Number of area-corrected 238U counts on unknown sample ρu-sp: Density of area-corrected 238U counts on unknown sample Nu-std : Total count of 238U on Uranium Standard sample ρu-std: Density of 238U counts on Uranium Standard sample P (χ2) : probability of obtaining the χ2 value for ν degrees of freedom (ν = number or crystals - 1)  Zeta value for fission track age calibration : 41.5 ± 1.5 (yr・cm-2) age: t = (1/λD)・ln [1+λD・ζ・(Ns /Nu-sp)・ρu-std ] error: σt = t×[1/ΣNs + 1/ΣNu-sp + 1/ ΣNu-std +(σζ/ζ)2]1/2  total decay constant of 238U: λD = 1.55125×10-10 yr-1 Appendix 1C [Foot Note]  *Particles excluded from dating **E.S.: External Surface Ns: Number of counted fission tracks  ρs: Spontaneous fission track density Nu-sp: Number of area-corrected 238U counts on unknown sample ρu-sp: Density of area-corrected 238U counts on unknown sample Nu-std : Total count of 238U on Uranium Standard sample ρu-std: Density of 238U counts on Uranium Standard sample P (χ2) : probability of obtaining the χ2 value for ν degrees of freedom (ν = number or crystals - 1)  Zeta value for fission track age calibration : 43.9 ± 1.4 (yr・cm-2) age: t = (1/λD)・ln [1+λD・ζ・(Ns /Nu-sp)・ρu-std ] error: σt = t×[1/ΣNs + 1/ΣNu-sp + 1/ ΣNu-std +(σζ/ζ)2]1/2  total decay constant of 238U: λD = 1.55125×10-10 yr-1</div