綱木坂向斜は気仙沼市東方唐桑地域に位置し,日詰-気仙沼線の東側にあたっている.ここでは,二畳系の登米層群から白亜系の鼎ケ浦層までが,同一のしゅう曲軸をもつ大きな向斜構造をなしている。下位の二畳・三畳系では,しゅう曲軸面に平行なスレートへき開が一様(N10°E,80°〜90°E)に密に発達しているのが特徴であり,その変形様式は種々の小構造からしても,また,地層の分布から知られる大構造からしても,東翼で厚く西翼で薄い,非対称せん断しゅう曲である.中部ジュラ系の唐桑層群では,スレートへき開は,下位層中のものと同一の方向に発達するが,それにくらべて発達が弱く,不規則断続的である.また,一部では層理面での滑りを伴なう.したがって,その変形様式は,典型的なせん断しゅう曲と曲げしゅう曲の中間型に相当する.上部ジュラ系の鹿折層群では,もはやスレートへき開は存在せず,層理面での滑りを伴なった典型的な曲げしゅう曲である.顕微鏡でスレートへき開の密度を測定すると,下位層から上位層にゆくにしたがって漸次減少し,ついにはまったくゼロになる.また,稲井層群や唐桑層群の基底には不整合面が存在するが,これらの面を境にして変形の様式が急に変るようなことはない.以上の観察から,下位から上位にゆくにしたがって,せん断しゅう曲から曲げしゅう曲に変り,両者の関係は漸移的であることがわかった.さらに,綱木坂向斜は一回の(あるいは一つづきの)地殻運動によってできたもので,両老の変形様式の相異は,主として封圧など"深さ"による物理条件の相異によると考えられる.

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The Plio-Pleistocene strata in Japan is typified by the marine Kazusa group in Kanto district and the aqueous Osaka group in Kinki district. On these groups, numerous studies of stratigraphy, paleontology, paleomaganetism, and so on, were reported, and the Plio-Pleistocene boundary was discussed from several view points. The pollen flora of the Kazusa group along the Yoro river was investigated by the writer and the results are summerized as follows. 1) There are two steps in the disappearance of the Pinus trifolia flora; a) Keteleeria and Pseudolarix? become extinct at the middle part of the Umegase formation (between U6 and U10), and b) Metasequoia and Picea A, at the middle of the Kokumoto formation. 2) By the sequence of the disappearance of the Pinus trifolis flora and the pollen composition, the Kazusa group is divided into six zones. 3) The correlation of the pollen zone of the Kazusa group and the Plio-Pleistocene flora in Kinki district may be shown as follows; Zone 1...Pinus trifolia flora and Transitional flora 1 Lower half of Zone 2...Transitional flora 2 Upper half of zone 2 and Zone 3...Metasequoia flora Zone 4 ...Paliurus nipponicus flora and 4) The Plio-Pleistocene boundary, as defined in the Osaka group, should be drown between U6 and U10.

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Thermal conductivity, elastic wave velocities, and density of andesites are measured at the room temperature and pressure condition. Samples are colected from the Miocene andesitic rocks at the Noto Peninsula and many of them are identified petrographically as augite-hypersthene andesite. Thermal conductivity is measured by devidedbar or steady state method. Error of our apparatus for individual measurement is assured less than 5%. Average of 26 samples is 4.13±0.76 (s.d.)×10^-3 cal/cm. sec. deg.. Elastic wave velocites are determined by ultra-sonic-pulse method. 1 Mc TiBaO3 exciter and reciever are used. Error is estimated less than 3% for langitudinal wave and 5% for transvers wave. Average velocities are 5.47±0.34(s.d.) km/sec and 3.30±0.18(s.d.) km/sec for longitudinal and transverese wave, respectively. Average density and porosity are 2.62±0.06(s.d.) gr/cm³. and 2.03±1.20(s.d.)%, respectively. Relation between thermal conductivity and elastic wave velocity is discussed based upon solid-state physics. As a result, phonon conductivity of present samples has an approximately linear relation with velocity as Kph=1.13×10^-8×W, where W=3^1/3(1/Vp³+2/Vs³)^1/3. Palaeomagnetism at the Noto Peninsula is also studied for the same samples as measured physical properties. Natural remanent magnetization is measured by astatic magnetometer and stability is tested by AC-demagnetization method. Conclusions are as follows ; Anamizu formation (about 2.5×10⁷ years ago) was formed under geomagnetic reversal field: Yanaida formation (about 2.0×10⁷ years ago) and Kurosaki andesites (about 1.0×10⁷ years ago) were formed under geomagnetic normal field.

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