• Title/Summary/Keyword: 지구조적환경

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신암리각섬암의 암석화학과 지구조적 의의

  • 박영석;김정빈;김종균
    • Proceedings of the KSEEG Conference
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    • 2003.04a
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    • pp.302-305
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    • 2003
  • 진안-장수지역 (이하 본 역)은 한반도를 구성하는 중요한 지괴인 영남육괴 지리산지역의 북서부와 옥천지향사대의 동남연변부에 위치한 곳으로 두 지괴의 경계면을 따라 압쇄작용으로 형성된 순창전단대가 분포하며 지질시대와 암석학적 특징이 상이한 여러 화성암체가 나타난다. 본 연구지역의 지질은 지리산 편마암복합체를 기반으로 선캠브리아기의 변성퇴적암류, 신암리섬암, 장수화강편마암, 선각산화강편마암 그리고 쥬라기의 대성리엽리상화강암, 순창엽리상화강암과 남원화강암으로 구성된다. (중략)

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Geochemical characteristics of Ogcheon granite in Ogcheon area (옥천화강암의 지구화학적 특성)

  • 윤현수;김대업;박석환
    • The Journal of the Petrological Society of Korea
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    • v.8 no.2
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    • pp.81-91
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    • 1999
  • The area of the study is located in Ogcheon district, middle part of Ogcheon Fold Belt. The area is covered by metasedimentary rocks of Ogcheon Supergroup at northern, eastern and southern part. Jurassic Ogcheon granite which intruded into Ogcheon Supergroup at central part, was intruded by Cretaceous quartz porphyry at western part. The granite consists of quartz, plagioclase, alkali feldspar, biotite, sphene, apatite, epidote, opaque and so on. It is generally characterized by grey to light grey, medium-grained, mafic enclave and partly weak foliation. In terms of geochmical compositions, the granite is felsic, peraluminous, subalkaline and calc-alkaline, and it was differentiated from single granitic magma. It shows parallel LREE enrichment and HREE depletion patterns with 0.84 Eu negative anomaly, which has REE variation trend and anomaly value similar to Jurassic granites in Korea. From charactristics of petrology, mineralogy and geochmistry, it may be interpreted that the Ogcheon granite body was derived from melting of I-type crustal material related to syn-collisional tectonic setting and emplaced more or less rapidly into the Ogcheon Supergroup.

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High-Resolution of Paleoenvironmental Reconstruction and Sea-Level History in Delaware Bay, the East Coast of U.S.A. (미국동부 델라웨어만의 고정밀도 해수면 역사와 고환경 복원)

  • YI, HI-IL;WEHMILLER, JOHN F.
    • 한국해양학회지
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    • v.30 no.4
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    • pp.320-331
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    • 1995
  • The closely spaced cores were analyzed to find detailed reconstruction of paleoenvironments and sealable changes along the Delaware Bay coast. Three areas, Kitts Hummock Beach mars, the St. Jones River marsh, and Bowers marsh near the St. Jones River's mouth, were chosen because these areas are compose of their own geomorphic characteristics and sea-level history. since significance of the stratigraphic correlations was to determine sedimentary fancies and paleoenvironments, multidisciplinary methods such as lithological description, grain-size analysis, organic/inorganic content, water content, mineral composition, botanical analysis, micropaleontological analysis, and /SUP 14/C datings were performed. Five major divisions of marsh environments were recognized in the stratigraphic sections: freshwater marsh, initialfreshwater marsh, slightly brackish marsh, brackish marsh, and salt marsh. Most of the lower part in the stratigraphic sections show freshwater marsh. On the top of this, either brackish marsh or tidal flat/tidal stream was recorded. The pro-Holocene sediments consist of sand, mud, and sandy mud, The pre-Holocene configuration played an important role for developing the Holocene Paleoenvironmental changes. The irregular configuration of the pre-Holocene sediments consist of sand, mud, and sandy mud. The pre-Holocene configuration played an important role for developing the Holocene Paleoenvironmental changes. The irregular configuration of the pre-Holocene surface within short distances permitted the concurrent development of variable environments such as freshwater marsh, brackish marsh or salt marsh at similar elevations. The freshwater marsh in this case was formed in the areas of isolation, so saline-water cannot encroach upon these areas. This complex development of paleoenvironments leads to a difficulty in stratigraphic correlation and interpretation of local relative sea-level changes. The deposition of subsurface sediments was affected by sediment supply, compaction, fluvial activity, biological competition, local tectonics and isostacy, climate and local relative sea-level changes. It was interpreted that the positions in the changes from freshwater environments to brackish environments or ice versa are the turning points of transgressions and regressions. Therefore, multiple transgressions and regressions were identified in the stratigraphic sections of the study area.

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