巻号一覧
41 巻, 1 号
選択された号の論文の9件中1～9を表示しています
- |<
- <
- 1
- >
- >|
-
Nd同位体比による検討加々美 寛雄, 小出 良幸原稿種別: 本文
1987 年 41 巻 1 号 p. 1-22
発行日: 1987/01/25
公開日: 2017/06/06
ジャーナル オープンアクセスSm/Nd system is more suitable than Rb/Sr system to clarify the formation process of upper mantle. We have collected many Nd isotopic data for intermediate, basic and ultra-basic igneous rocks from many parts of the world. These data have been re-calculated as εNd value (DEPAOLO & WASSERBURG, 1976a) using bulk earth's parameters as follows; 143Nd/144Nd (present ratio)=0.512640, 147Sm/144Nd=:0.1967, λ(147Sm)=6.54×10_-12 y_-1. These εNd values have been plotted in Fig. 2. Fig. 1 is shown more precisely than Fig. 2. We have examined this figure and field relationships for rocks quoted in this figure in detail, and furthermore, examined the εNd values for rocks as follows; intermediate and basic igneous rocks being younger than late Cretaceous (Fig. 3), acid igneous rocks (Fig. 4), kimberlites, alkali basalts, mantle origin nodules (Fig. 7). As the result, two models for the formation process of upper mantle are proposed, which are shown in Fig. 5 (Model-1) and Fig. 6 (Model-2). These models are reasonable in normal region, but unreasonable in Dupal anomaly (HART, 1984) and its surrounding regions. The difference between Model-1 and Model-2 is mainly due to that of the formation process of oceanic lithosphere. For determination of real model, it is necessary to study the ophiolites which are older than l.3 Ga.抄録全体を表示PDF形式でダウンロード (2449K) -
佐野 栄原稿種別: 本文
1987 年 41 巻 1 号 p. 23-34
発行日: 1987/01/25
公開日: 2017/06/06
ジャーナル オープンアクセスThe auther has examined mantle heterogeneity by using the neodymium isotope data of oceanic region. It has been stated that the εNd values of MORBs originating from the most depleted mantle are characterized by the range between +9 and +12, However, from many collected data, it has been recognized that the εNd values of +10 and over are rare. The most depleted MORBs are distributed in restricted region of the Northern Hemisphere. On the other hand, the MORBs of the Southern Hemisphere are characterized by low εNd values as compared with those of the Northern Hemisphere, and form the isotopically anomalous zone. The most of new εNd data concentrate between +7 and +10, and the ranges of those values are different in each ocean. The εNd values of OIBs in the Southern Atlantic and the Indian Oceans are +1 to -2. They are lower than those of the other OIBs. It has been suggested that large-scale Pb and Sr isotopic mantle anomalies (Dupal anomaly) exist in the Southern Hemisphere. On neodymium isotopic composition, the auther also has been recognized the anomalous zone in the Southern Atlantic and the Indian Oceans. Furthermore, it has been clearly that the anomaly on OIBs is found in the same area on MORBs.抄録全体を表示PDF形式でダウンロード (1578K) -
渡辺 寧, 岩田 圭示原稿種別: 本文
1987 年 41 巻 1 号 p. 35-47
発行日: 1987/01/25
公開日: 2017/06/06
ジャーナル オープンアクセストムラウシ地域の日高累層群は主として,黒色頁岩,灰色珪質頁岩,細粒砂岩,緑色または赤色頁岩,チャート,緑色岩より構成される.この地域の日高累層群は,整合一連の堆積物のようであり,次の7つのユニットに分類できる.(1)珪質頁岩,砂岩を含む黒色頁岩層,(2)黒色頁岩優勢砂岩・頁岩互層,(3)黒色頁岩を含む緑色岩層,(4)礫岩を含む黒色頁岩層,(5)緑色又は赤色頁岩層,(6)砂岩優勢砂岩・泥岩互層,(7)珪質頁岩を含む黒色頁岩層.この地域の日高累層群の年代は放散虫化石によると後期白亜紀と考えられる.これらの堆積物中には,前期アルビアンから後期セノマニアンを示すチャートの外来岩塊が含まれる.堆積岩の全岩化学組成の検討によると,緑色(赤色)頁岩やチャートは,黒色頁岩,珪質頁岩よりも,より深海底の堆積物の特徴を示す.この地域の日高累層群の砂岩は,湧別・サロマ層群のものとは明らかに異なり,メナシュマン層や,函淵・中の川層群の一部と類似性を示す.抄録全体を表示PDF形式でダウンロード (1368K) -
鈴木 清一, 都郷 義寛原稿種別: 本文
1987 年 41 巻 1 号 p. 48-56d
発行日: 1987/01/25
公開日: 2017/06/06
ジャーナル オープンアクセスThe internal structure and mineralogy of the calcined opercula of five species of turbinid gastropods have been studied. The operculum consists of the inner organic and the outer calcified layers; the latter contains a small amount of organic matrix. In all species examined, the calcified layer has a shell microstructure of composite prismatic type. This microstructure is composed principally of acicular to thin prismatic aragonite crystals of about 0.1 to 1 μm in diameter, such componental crystals being aggregated to form a larger unit of the structure. The composite prismatic structure of the turbinid operculum is much more variable in form, size and branching manner of the aggregation of acicular crystals than that of the bivalvian shell. Furthermore, this microstructure of the operculum occasionally tends to change in structure by excessive enlargement in diameter of the componental crystals and has a structural similarity to an irregular prismatic type of the molluscan shell. Observations of such structural change indicate that the proportion of crystal nucleation and growth of the normal composite prismatic type may be strictly controlled by a physiological condition, for example, density of the secretion fluid, of the animal. In many individuals regardless of the species, small patches composed of a calcite blocky structure are present within the aragonite composite prismatic region. Judging from the internal thin bands (growth structure) of the patches and contact relation with the neighboring aragonite prisms, the calcite patches may initially be formed together with the surrouding aragonite parts. This occurrence may indicate that there is no obvious difference on the depositional conditions between aragonite and calcite in biological systems.抄録全体を表示PDF形式でダウンロード (5050K) -
神居古潭構造帯の蛇紋岩の迸入時期についての新資料永田 秀尚, 紀藤 典夫, 中川 充原稿種別: 本文
1987 年 41 巻 1 号 p. 57-60
発行日: 1987/01/25
公開日: 2017/06/06
ジャーナル オープンアクセスPDF形式でダウンロード (781K) -
木村 方一, 国分 英彦, 熊野 純男, 松井 愈原稿種別: 本文
1987 年 41 巻 1 号 p. 61-64a
発行日: 1987/01/25
公開日: 2017/06/06
ジャーナル オープンアクセスPDF形式でダウンロード (881K) -
田沢 純一, 金子 篤原稿種別: 本文
1987 年 41 巻 1 号 p. 65-68
発行日: 1987/01/25
公開日: 2017/06/06
ジャーナル オープンアクセスPDF形式でダウンロード (572K) -
日本の第四紀層の14C年代(162)中馬 教允, 出口 一盛, 佐藤 美穂子, 宮田 寿美子, 大塚 克也原稿種別: 本文
1987 年 41 巻 1 号 p. 69-70
発行日: 1987/01/25
公開日: 2017/06/06
ジャーナル オープンアクセスPDF形式でダウンロード (196K) -
日本の第四紀層の14C年代(163)岡田 篤正, 森 忍原稿種別: 本文
1987 年 41 巻 1 号 p. 71-73
発行日: 1987/01/25
公開日: 2017/06/06
ジャーナル オープンアクセスPDF形式でダウンロード (413K)
- |<
- <
- 1
- >
- >|