朝鲜平南盆地古元古界-下古生界沉积岩碎屑锆石年龄谱对比及意义   总被引：3，自引：3，他引：0  

杨正赫  彭澎  郑哲寿  朴雄  文正根  金哲贤  苟贤哲 《岩石学报》2016,32(10):3155-3179

中朝古陆(华北古陆)平南盆地面积~25000km~2,位于朝鲜半岛中部,发育从中元古界到下古生界地层,但经历了低级变质作用(绿片岩相及以下)。变质基底岩石中有一套角闪岩相-麻粒岩相的变质的古元古界地层。本文根据盆地不同时代沉积岩碎屑锆石/变质锆石U-Pb LA-ICP MS年龄数据讨论沉积源区的变化,并对区域演化进行制约。甑山群/杂岩为盆地基底岩系,变质砂岩样品中碎屑锆石出现ca.2500~2100Ma的年龄峰值。另外,36.5亿年的碎屑锆石是朝鲜迄今发现的最古老碎屑锆石;夕线榴片麻岩样品记录了~1850Ma(1859±9Ma)的变质年龄;推测甑山群沉积于ca.2100~1900Ma,变质于1850 Ma。黄海群局限分布于朝鲜半岛中部,碎屑锆石年龄谱显示~1850 Ma的峰值,可见~1250 Ma的年龄,推测对应物源为古元古代基底岩浆岩和变质岩系;结合其上覆直岘群的沉积时代,推测地层沉积于ca.1250~1000Ma。直岘群是平南盆地分布最广的地层之一,底部长峰组样品显示明显的~1850Ma的峰值,而其上第二个和第三个组则显示明显的ca.1400~1600Ma和ca.1000~1200 Ma年龄峰值,~1850 Ma年龄很少;推测直岘群开始沉积时,物源主体是盆地基底岩系,但之后出现大量中元古代物质;推测其沉积时代为ca.1000~900Ma。黄州群有~1850Ma和~2500Ma的峰值,另外,还有较少的ca.1000~1200Ma及1400~1600 Ma年龄,表明沉积物源主体仍是基底岩系,可能有中新元古代沉积岩(黄州群-直岘群)的再沉积。这些沉积岩碎屑锆石年龄峰值与辽东和山东半岛沉积地层相似,并且中新元古代地层中均有大量1000~1200Ma及1400~1600Ma的物质,推测可能来自华北古陆之外,如圣弗朗西斯科克拉通。  相似文献   

白头山火山渣锥的岩浆演化研究     

朴成哲  金东旭  赵日元  金守哲  金仁哲 《岩石学报》2016,32(10):3214-3224

火山渣锥是白头山(或长白山)火山喷发的重要产物,主要沿熔岩台地周边呈圆锥状寄生小火山锥体分布。野外特征显示,火山渣是火山渣锥的重要组成;岩石手标本显示,火山渣具有气孔构造,样品自顶部至底部,颜色从赤色、赤褐色,向褐色、灰色发生转变。地球化学特征表明,火山渣岩性包括玄武岩、粗面玄武岩、玄武岩质粗面安山岩、粗面安山岩岩,具有较高SiO_2(46.22%~55.38%),Al_2O3含量(15.28%~22.11%),低MgO(2.05%~4.94%),FeOT(6.79%~14.76%)的特征;同时具有较高的碱Na_2O/K_2O(Na_2O/K_2O1)比值,为钠质火山岩。其轻稀土(LREE)和重稀土(HREE)分异明显,具有弱的δEu正异常,并且具有富集K、Rb、Ba、Sr等大离子亲石元素(LILE)和相对亏损Nb、Ti等高场强元素(HFSE)的特征。此外,火山渣的分异指数(DI)范围为36.93~64.48,高于造盾阶段的幔源玄武岩的分异指数;其固结指数(SI)为10.73~24.09,低于早期幔源玄武岩的固结指数(SI=25~45),这些特征说明火山渣成分发生了较高程度的岩浆分异作用。同时,火山渣的Nb/La、Sm/Nd、La/Nb和Ba/Nb比值几乎全部介于幔源玄武岩和大陆地壳之间,说明具有明显的地壳混染的特征。因此,我们认为研究区火山渣的岩浆可能是由幔源基性玄武岩上升过程中发生分离结晶和地壳混染作用形成的。  相似文献   

Geochemistry and Petrogenesis of Neoarchean Metamorphic Mafic Rocks in the Wutai Complex   总被引：1，自引：0，他引：1  

K. H. PARK 《《地质学报》英文版》2006,80(6):899-911

Neoarchean metamorphic mafic rocks in the lower and the middle Wutai Complex mainly comprise metamorphic gabbros, amphibolites and chlorite schists. They can be subdivided into three groups according to chondrite normalized REE patterns. Rocks in Group #1 are characterized by nearly flat REE patterns （Lan/Ybn=0.86-1.3）, the lowest total REEs （29-52 ppm）, and weak negative to positive Eu anomalies （Eun/Eun=0.84-1.02）, nearly flat primitive mantle normalized patterns and strong negative Zr（Hf） anomalies. Their geochemical characteristics in REEs and trace elements are similar to those of ocean plateau tholeiite, which imply that this group of rocks can represent remnants of Archean oceanic crust derived from a mantle plume. Rocks in Group #2 are characterized by moderate total REEs （34-116 ppm）, LREE-enriched （Lan/Ybn=1.76-4.34） chondrite normalized REE patterns with weak Eu anomalies （Eun/Eun=0.76-1.16）, and negative Nb, Ta, Zr（Hf）, Ti anomalies in the primitive mantle normalized spider diagram. The REE and trace element characteristics indicate that they represent arc magmas originating from a sub-arc mantle wedge metasomatized by slab-derived fluids. Rocks in Group #3 are characterized by the highest total REEs （61-192 ppm）, the strongest LREEs enrichment （Lan/Ybn=7.12-16） with slightly negative Eu anomalies （Eun/Eun=0.81-0.95） in the chondrite normalized diagram. In the primitive mantle normalized diagram, these rocks are characterized by large negative anomalies in Nb, Ta, Ti, negative to no Zr anomalies. They represent arc magmas originating from a sub-arc mantle wedge enriched in slab-derived melts. The three groups of rocks imply that the formation of the Neoarchean Wutai Complex is related to mantle plumes and island-arc interaction.  相似文献   

The Effect of the Irrigated Gudeuljang Paddy System on Biodiversity on Cheongsan-do (“island”)     

PARK Eunha  OH Choong-Hyeon 《资源与生态学报(英文版)》2016,7(3):218-222

This study has been conducted to identify the characteristics of the biodiversity promoted and maintained by gudeuljang paddy field. For this purpose, a literature review was used to identify the distribution of gudeuljang paddy field on Cheongsan-do. Based on the results of the review, a target area was selected to conduct an investigation of the flora of the vascular plants and a phytosociological examination, which included general farmlands and neighboring areas, was made for comparison. As a result of the study, we were able to identify the differences between the type of gudeuljang paddy field that uses continuous irrigation and other types of land use. We found that the unique physical structure for water passage found in gudeuljang paddy fields with continuous irrigation is more effective in promoting biodiversity than the other types of land use in this area. In conclusion, the presence of gudeuljang paddy fields on Cheongsan-do contributes more to the creation of an appropriate biohabitat than it detracts from such a creation. Also, the presence of gudeuljang paddy fields is significant in that it exercises positive influence on the promotion of biodiversity, such as propagation of species, and the connection of habitats in adjacent forest, village, and farm lands. Our result shows that the maintenance and preservation of gudeuljang paddy fields on Cheongsan-do plays a crucial part in the preservation and maintenance of the biodiversity for vegetation that grows among rocks and in adjacent forest areas.  相似文献   

Integration of the nuclease protection assay with sandwich hybridization (NPA-SH) for sensitive detection of Heterocapsa triquetra     

PARK Mirye  PARK So Yun  HWANG Jinik  JUNG Seung Won  LEE Juyun  CHANG Man  LEE Taek-Kyun 《海洋学报(英文版)》2018,37(5):107-112

Microalgae are photosynthetic microorganisms that function as primary producers in aquatic ecosystems. Some species of microalgae undergo rapid growth and cause harmful blooms in marine ecosystems. Heterocapsa triquetra is one of the most common bloom-forming species in estuarine and coastal waters worldwide. Although this species does not produce toxins, unlike some other Heterocapsa species, the high density of its blooms can cause significant ecological damage. We developed a H. triquetra species-specific nuclease protection assay sandwich hybridization (NPA-SH) probe that targets the large subunit of ribosomal RNA (LSU rRNA). We tested probe specificity and sensitivity with five other dinoflagellates that also cause red tides. Our assay detected H. triquetra at a concentration of 1.5×10⁴ cells/mL, more sensitive than required for a red-tide guidance warning by the Korea Ministry of Oceans and Fisheries in 2015 (3.0×10⁴ cells/mL). We also used the NPA-SH assay to monitor H. triquetra in the Tongyeong region of the southern sea area of Korea during 2014. This method could detect H. triquetra cells within 3 h. Our assay is useful for monitoring H. triquetra under field conditions.  相似文献   

Recent Advancement in Modeling Seafloor Dissipative Mechanism in Shallow Water     

Philip L.-F.LIU  Yong Sung PARK 《中国海洋工程》2008,22(1):1-10

In this paper, the recent development in modeling seabed dissipative mechanisms in shallow water is reviewed. Specifically, laminar and turbulent boundary layer solutions as well as viscous mud flow solutions under transient waves are presented. These analytical solutions are compared with experimental data for both solitary waves and cnoidal waves. Very goed agreement is ohtained. The Boussinesq equations with boundary layer effects and the muddy seabed effects are also shown.  相似文献   

Geochemistry, Nd Isotopic Characteristics of Metamorphic Complexes in Northern Hebei： Implications for Crustal Accretion   总被引：4，自引：0，他引：4  

K. H. PARK 《《地质学报》英文版》2006,80(6):807-818

The middle segment of the northern margin of the North China Craton （NCC） consists mainly of metamorphosed Archean Dantazi Complex, Paleoproterozoic Hongqiyingzi Complex and unmetamorphosed gabbro-anorthosite-meta-alkaline granite, as well as metamorphosed Late Paleozoic mafic to granitoid rocks in the Damiao-Changshaoying area. The -2.49 Ga Dantazi Complex comprises dioritic-trondhjemitic-granodoritic-monzogranitic gneisses metamorphosed in amphibolite to granulite facies. Petrochemical characteristics reveal that most of the rocks belong to a medium- to high-potassium calc-alkaline series, and display Mg^# less than 40, right-declined REE patterns with no to obviously positive Eu anomalies, evidently negative Th, Nb, Ta and Ti anomalies in primitive mantlenormalized spider diagrams, εNd（t）=＋0.65 to -0.03, and depleted mantle model ages TDM=2.78-2.71 Ga. Study in petrogenesis indicates that the rocks were formed from magmatic mixing between mafic magma from the depleted mantle and granitoid magma from partial melting of recycled crustal mafic rocks in a continental margin setting. The 2.44-2.41 Ga Hongqiyingzi Complex is dominated by metamorphic mafic-granodioritic-monzogranitic gneisses, displaying similar petrochemical features to the Dantazi Complex, namely medium to high potassium calc-alkaline series, and the mafic rocks show evident change in LILEs, negative Th, Nb, Ta, Zr anomalies and positive P anomalies. And the other granitiod samples also exhibit negative Th, Nb, Ta, P and Ti anomalies. All rocks in the Hongqiyingzi Complex show right-declined REE patterns without Eu anomaly. The metamorphic mafic rocks with εNd（t） = -1.64 may not be an identical magmatic evolution series with granitoids that have εNd（t） values of ＋3.19 to ＋1.94 and TDM ages of 2.55-2.52 Ga. These granitic rocks originated from hybrid between mafic magma from the depleted mantle and magma from partial melting of juvenile crustal mafic rocks in an island arc setting. All the -311 Ma Late Paleozoic metamorphic mafic rocks and related granitic rocks show a medium-potassium calc-alkaline magmatic evolution series, characterized by high Mg^#, obviously negative Th, Nb, Ta anomalies and positive Sr anomalies, from no to strongly negative Ti anomalies and flat REE patterns with εNd（t） = ＋8.42, implying that the maflc magma was derived from the depleted mantle. However the other granitic rocks are characterized by right-declined REE patterns with no to evidently positive Eu anomalies, significantly low εNd（t） = -13.37 to -14.04, and TDM=1.97-1.96 Ga, revealing that the granitoid magma was derived from hybrid between maflc magma that came from -311 Ma depleted mantle and granitoid magma from Archean to Early Paleoproterozoic ancient crustal recycling. The geochemistry and Nd isotopic characteristics as well as the above geological and geochronological results indicate that the middle segment of the northern margin of the NCC mainly experienced four crustal growth episodes from Archean to Late Paleozoic, which were dominated by three continental marginal arc accretions （-2.49, -2.44 and 311 Ma）, except the 1.76-1.68 Ga episode related to post-collisional extension, revealing that the crustal accretion of this segment was chiefly generated from arc accretion and amalgamation to the NCC continental block.  相似文献   

Physiological differences in the growth and maturation of Eisenia bicyclis and Ecklonia cava gametophytes in Korea     

Han Gil CHOI  Da Vine JEON  Seo Kyoung PARK  GAO Xu 《中国海洋湖沼学报》2019,(2)

The objective of this study was to examine the ef fects of temperature and light intensity on growth of female gametophytes of Eisenia bicyclis and Ecklonia cava and responses of these female gametophytes to Fe addition and daylength. Female gametophytes of each species were cultured at four temperatures(10, 15, 20, and 25°C) and under a combination of four light intensities(10, 20, 40, and80 μmol photons/(m 2 ·s)) with two temperatures(15 and 20°C for E i. bicyclis; 20 and 25°C for E c. cava) to clarify their optimal growth conditions. Growth and maturation of female gametophytes of these two species under a combination of five Fe-EDTA concentrations(0, 1, 2, 4, and 8 μmol/L) and three daylengths(10,12, and 14 h) were also examined. The growth of E i. bicyclis gametophyte was maximal at approximately15–20°C, 20 μmol photons/(m 2 ·s), Fe-EDTA concentration of 8 μmol/L and daylengths of 12–14 h. While E c. c ava gametophytes showed optimal growth at approximately 20–25°C, 20 μmol photons/(m 2 ·s), FeEDTA concentration of 8 μmol/L and daylength of 14 h. Maturation of gametophytes was enhanced at Fe-EDTA concentration of 4 μmol/L for E i. bicyclis and at 2 μmol/L for E c. c ava. In conclusion, optimal growth temperatures and Fe-EDTA concentrations for maturation of E i. bicyclis and E c. c ava gametophytes were dif ferent. Higher optimal growth temperature for E c. c ava gametophytes may contribute to its wider geographical distribution compared to E i. bicyclis which has restricted habitats in Korea. This suggests that addition of Fe ion could be used to recover beds of these two species in barren grounds of Korea.  相似文献   

Mineral Chemistry and Age Dating of W-skarn Deposit at Weondong mine,Taebak in Korea     

Chang-Yoon PARK  Yungoo SONG  Il-Mo KANG  Donghoon JUNG  Khulganakhuu CHULUUNBAATAR 《《地质学报》英文版》2013,87(Z1):676-677

  相似文献   

朝鲜平南盆地祥原超群的沉积时代与拉伸纪早期碳同位素负漂移   总被引：4，自引：4，他引：0  

朴贤旭  翟明国  杨正赫  彭澎  金正男  张艳斌  金明哲  朴雄  冯连君 《岩石学报》2016,32(7):2181-2195

朝鲜平南盆地与东华北克拉通(中朝克拉通)中新元古代盆地的对比存在争议,准确厘定相关沉积建造的沉积时限是解决这些争议的关键。朝鲜平南盆地的地层主体为祥原超群,从下往上依次为直岘群、祠堂隅群、默川群、灭恶山群和燕滩群。直岘群是祥原超群的最下部层位,大部分由陆源碎屑岩组成。从平南盆地"北部型"和"南部型"直岘群碎屑岩中分选锆石,测得LA-ICP-MS U-Pb年龄,限定祥原超群沉积时代晚于1100Ma,并且得出所谓的"北部型"和"南部型"地层没有时代和物源差异。鉴于默川群的基性岩床时代为~900Ma,祥原超群的沉积时代为新元古代早期(1000~900Ma),燕滩群的时代可能稍晚。这说明平南盆地与华北徐淮盆地和旅大盆地等同时。祥原超群碳酸盐岩样品的δ~(13)C值数据表明,默川群时期碳同位素发生了负漂移(δ~(13)C值为-6‰~-5‰)。鉴于侵入到默川群的基性岩床的时代为~900Ma,我们认为该碳同位素(δ~(13)C值)负漂移略早于~900Ma,可能与同一时期的岩浆活动有关。  相似文献