トロムセ・ナップに産する正片麻岩の主要構成鉱物はざくろ石、白雲母、斜長石、石英である。ざくろ石は自形性がよく数十μmから1mm程度で、組成累帯構造が認められる；(1) Caに乏しくYに富み、包有物を多数含むコア、(2) CaとYに乏しく包有物をほとんど含まないリム、(3) Caに富みYに乏しい外部リム。コアの包有物は石英、白雲母、ジルコン、ルチルと稀に藍晶石が認められる。X線マッピング像によるCaやYの不連続面をコア‐リム境界と考えた。また不連続面の輪郭は丸みを帯びており、コア形成後にざくろ石が一旦溶融し、その後に再成長した可能性を示唆している。斜長石はCaに富むコアとCaに乏しいリムからなる。斜長石のリムはザクロ石の外部リムへのCaの供給源とみなすことができる。ざくろ石の形成過程について発表を行う。

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 Weathering is deeply related to global climate change. In the carbon cycle, silicate weathering, especially volcanic rock weathering, transfers carbon in the atmosphere (as CO₂) to the lithosphere, and oxidative weathering of organic matter releases carbon (as CO₂) from the biosphere to the atmosphere. Moreover, as an indirect effect of weathering on climate change, negative feedback in the climate system, which results from the dependence of weathering rate on temperature and evolution of terrestrial plants, is crucial. It has stabilized the long-term global climate throughout the Phanerozoic. Weathering rate is controlled by several geochemical external factors: tectonic forces such as lithology, continental uplift, and continental drift (paleogeography); climate forces such as temperature, runoff, and glaciations; and, biological forces such as terrestrial plant evolution. Regarding biological forces, accelerated weathering assisted by ectomycorrhizal fungi (EM fungi) and arbuscular mycorrhizal fungi (AM fungi), as well as vascular plants of gymnosperms and angiosperm, are emphasized. Variations of global weathering in the geological past are estimated using experimental approaches, such as isotope analysis (e.g., ⁸⁷Sr/⁸⁶Sr, ¹⁸⁷Os/¹⁸⁶Os, δ⁷Li), and theoretical approaches, such as numerical simulations (e.g., carbon cycle model). Each is used differently according the purpose of a study. Based on these estimates, geological past climate changes in the Phanerozoic are found to be closely related to weathering. For example, on the order of magnitude of 10⁷ years, changes in weathering patterns due to continental drift (paleogeography) have resulted in variations of atmospheric CO₂, hence climate change. On the order of magnitude of 10⁶ years, it is suggested that a decrease in atmospheric CO₂ from the mid- to late Cretaceous was caused by enhanced weathering according to terrestrial plant evolution and that variations of atmospheric CO₂ in the late Cenozoic were regulated by weathering directly or indirectly influenced by continental uplift. Additionally, contributions of weathering to global climate change involved in oceanic anoxic events in the Mesozoic have been investigated.

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The global carbon cycle on a geological age consists of an inorganic carbon cycle (continental weathering and metamorphism-volcanism) and organic carbon cycle (oxidative weathering of organic carbon and organic carbon burial). The GEOCARB, one of the global carbon cycle models, calculates these geochemical carbon fluxes and atmospheric CO₂ level in the period of Phanerozoic.
  Important parameters in the GEOCARB are those for the continental uplift, river runoff, evolution of vascular plants, weathering feedback, and CO₂ degassings. Seawater strontium isotope ratio and sedimentation rate of terrigenous sediments can be used to estimate the continental uplift parameter. Regarding the vascular plant, more quantitative studies are necessary to elucidate its effect on the global carbon cycle. Concerning the degassing parameter, not only subduction volcanism but also hot spot volcanism and igneous activity in back arc basin should be considered. Runoff is dependent on continental positions and terrestrial temperature, but the interrelationship among them is not fully considered in the GEOCARB. In this respect, another type of the model, namely, the GEOCLIM, may be more appropriate.
  Volcanic rock weathering and climate sensitivity are also crucial in the global carbon cycle. Volcanic rock weathering might have controlled the atmospheric CO₂ level in the Phanerozoic, although the value of the weathering flux has not been constrained. Regarding the climate sensitivity, a short-term feedback (Charney feedback) has been assumed in the GEOCARB. However, a long-term climate feedback, namely, the Earth System Sensitivity (ESS), should be incorporated.
  According to the recent version of GEOCARB (GEOCARBSULF), most influential parameters on the atmospheric CO₂ are those for the climate sensitivity and vascular plants. In this model, atmospheric CO₂ level in the Cenozoic is not well consistent with the results of geochemical proxies. This may be due to the insufficient estimation of degassing parameters, and/or a change in the climate sensitivity accompanied with formation of continental ice sheets in the Cenozoic.

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