Yeosu dinosaur track sites of Korea: The youngest dinosaur track records in Asia     

In Sung Paik  Min Huh  Kye Hun Park  Koo Geun Hwang  Kyung Sik Kim  Hyun Joo Kim 《Journal of Asian Earth Sciences》2006,28(4-6):457-468

Eighty two dinosaur trackways were newly discovered in Upper Cretaceous lacustrine deposits on islands in the vicinity of Yeosu, Korea. Most dinosaur tracks occur in marginal lake deposits with polygonal desiccation cracks. The dinosaur tracks at the Yeosu site include 65 ornithopod trackways, 16 theropod trackways and one sauropod trackway. The prevalence of ornithopod tracks and the limited occurrence of sauropod tracks at the Yeosu site evidently reflect decreased sauropod diversity in the Upper Cretaceous. All ornithopod trackways represent bipeds, and most of the ornithopod tracks are similar to Caririchnium from other sites of the Korean peninsula. All fossil wood specimens collected in the study area represent conifers (three species of cupressaceous and two species of taxodiaceous conifers, and a new species) except for one, which is a discotyledon. It is thus inferred that the southwestern part of the Korean Peninsula was primarily covered with mesic forests with taxodiaceous trees during the Late Cretaceous. The K–Ar age of the Yeosu tracksite is determined as 81–65 Ma (Camapnian to Maastrichtian). It indicates that the Yeosu track site contains the last records of dinosaurs living in Asia. Consequently, semi-arid palaeoclimatic conditions, together with a large lake as a persistent water source and rich vegetation of gymnosperm trees as food, resulted in the preservation of abundant dinosaur tracks in the Upper Cretaceous on the Korean Peninsula.  相似文献   

格列菲列岛的地质地球物理研究     

CHOI Suckwon  Woo Youngkyun  Koo Minho  Suh Mancheol  郝天珧  王谦身 《地球物理学进展》2003,18(2):283-286

本文是中、韩国际合作项目“黄海地质地球物理场特征研究”的一部分 .具体研究了格列菲列岛的基础地质问题及地球物理场特征 .格列菲列岛是由三个小岛组成的位于黄海中部的一组群岛 ,位于朝鲜半岛布格重力异常正值区 ,莫霍面埋深在 2 9km左右 .三个岛屿主要由安山集块岩构成 .安山集块岩是由大小不同的火成岩碎块和熔岩混合而成 .火成岩的碎块成分主要为石英岩、片岩、片麻岩、玄武岩、安山岩和流纹岩 .主要节理方向为NE10°～NE2 0°,倾角近乎垂直 ;另一组节理为NW70°～NW80° ,倾角也近垂直 .本研究为我们了解这个地区的基础地质情况 ,岩石物性和随后进行的黄海海域典型剖面的地球物理物性反演工作以及地质模型的建立 ,打下重要基础 .  相似文献   

Towards an Interpretation of Historical Droughts in Northern Nigeria     

Aondover Tarhule  Ming-Ko Woo 《Climatic change》1997,37(4):601-616

Both historical information on sub-Saharan droughts/famines and measured rainfall data from northern Nigeria were analysed. Their parallel existence since 1905 allows famine chronologies to be quantified from the rainfall series. It is found that the most disruptive historical famines occurred when the cumulative deficit of rainfall fell below 1.3 times the standard deviation of long-term mean annual rainfall for a particular place. Thus defined, rainfall droughts matched approximately 90% of the famine events chronicled for northern Nigeria. An attempt is made to utilise information obtained from this matching of events to interpret droughts which occurred before scientific measurements. Difficulties inherent in such interpretation are discussed.  相似文献   

Constraints of Housing Age and Migration on Residential Mobility     

Dowell Myers  S. Simon Choi  Seong Woo Lee 《The Professional geographer》1997,49(1):14-28

This paper investigates the role of housing age in constraining residential mobility, measured as the percent of households that have moved into their homes in the past 15 months. The leading explanation for why mobility rates differ so much among regions of the United States has been the overall level of growth. The present analysis shows that the growth effect operates through both the newness of population (migration) and the newness of housing available for occupancy by all local residents. The posited explanation for this housing age effect is that progressively older units contain increasingly settled occupants, yielding fewer opportunities for in-movers in areas with older housing. It is empirically demonstrated that households in older housing have lower likelihood of recent mobility even after controlling for age, tenure, migration status, and state location of residence. The analysis reveals the temporal interdependency of mobility, migration, person age, and housing age.  相似文献   

The solar wind and the Sun–Earth link     

Prof.  Shadia Rifia Habbal Dr  Richard Woo 《Astronomy& Geophysics》2004,45(4):4.38-4.43

Plasma streams out from the Sun in the form of the solar wind. Shadia Rifai Habbal and Richard Woo examine the workings of this enigmatic link between the Earth and the Sun.  相似文献   

Determination of the elastic modulus set of foliated rocks from ultrasonic velocity measurements   总被引：2，自引：0，他引：2  

Insun Song  Mancheol Suh  Yong-Kyun Woo  Tianyao Hao 《Engineering Geology》2004,72(3-4):293-308

Ultrasonic measurements of compressional and shear wave velocities under hydrostatic pressure up to 70 MPa were carried out on cylindrical specimens cored across and along the foliation planes. Our measurements revealed that the foliation of the metamorphic rocks induces a clear velocity anisotropy between two orthogonal directions; faster along the foliation plane and slower across the plane in most rock types. All velocity components monotonically increase with the confining pressure, probably due to the closure of microcracks distributed in rock specimens. We determined the complete set of dynamic moduli of foliated metamorphic rocks with two assumptions; transverse isotropy due to the foliation and ellipsoidal seismic energy propagation from a point source. The calculated elastic moduli referring to different directions could be valuable for the design of various engineering structures in planar textured rock mass.  相似文献   

Tectonic elements with South China affinity in the Korean Peninsula: new Early Jurassic palaeomagnetic data   总被引：1，自引：0，他引：1  

Koji Uno  Tae Woo Chang  Kuniyuki Furukawa 《Geophysical Journal International》2004,158(2):446-456

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Cryohydrology in Canada: A brief history     

Ming‐ko Woo 《水文研究》2019,33(26):3407-3411

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Cambrian Stem-group Cnidarians with a New Species from the Cambrian Series 3 of the Taebaeksan Basin, Korea     

Tae-Yoon S. Park  Ji-Hoon Kihm  Jusun Woo  Yong-Yi Zhen  Michael Engelbretsen  Jongsun Hong  Suk-Joo Choh  Dong-Jin Lee 《《地质学报》英文版》2016,90(3):827-837

Five species, Lipopora lissa Jell and Jell, 1976, Lipopora daseia Jell and Jell, 1976, Tretocylichne perplexa Engelbretsen, 1993 from Australia, Cambroctoconus orientalis Park, Woo, Lee, Lee, Lee, Han and Chough, 2011 from China, and Cambroctoconus kyrgyzstanicus Peel, 2014 from Kyrgyzstan, belonging to the Cambrian stem-group cnidarians have been documented in the fossil record. Cambroctoconus coreaensis sp. nov., interpreted here as a stem-group cnidarian, from the Seokgaejae section in the Daegi Formation, Taebaek Group (Cambrian Series 3), Taebaeksan Basin, central-eastern Korean Peninsula, has a slender cup-shaped skeleton. A cladistic analysis produced 21 most parsimonious trees, which invariably placed the six stem-group cnidarians below the crown-group, but their relationships within the stem-group are unresolved. Nine out of the 21 trees suggest a monophyletic relationship for the Cambrian stem-group cnidarians, whereas in six other trees a monophyly of Cambroctoconus and Tretocylichne appeared as the sister-group to the crown-group cnidarians with Lipopora at the most basal branch. This result may reflect the fact that crown-group cnidarians evolved in the Precambrian, and suggests that the diversity of stem-group cnidarians was a result of an independent radiation in the Cambrian.  相似文献   

Rare earth element fingerprints in Korean coastal bay sediments: Association with provenance discrimination     

Jeongwon Kang  Han Jun Woo  Seok Jang  Kap-Sik Jeong  Hoi-Soo Jung  Ha Gi Hwang  Jun-Ho Lee  Jin Hyung Cho 《Ocean Science Journal》2016,51(3):305-316

Rare earth elements (REEs: La-Lu) in surface sediments collected from the mouth and middle tidal flats of Gomso Bay, South Korea, in August 2011 and May 2012 were analyzed to investigate the fine-grained sediment provenance. The upper continental crust (UCC)-normalized light REEs (LREEs: La to Nd) were more enriched than the middle REEs (MREEs: Sm to Dy) and heavy REEs (HREEs: Ho to Lu), resulting in large (La/Yb)_UCC (1.9 ± 0.4) to (Gd/Yb)_UCC (1.4 ± 0.2) ratios. The monthly (La/Yb)_UCC values differed between the mouth and middle tidal flats due to deposition of fine-grained sediments that originated from distant rivers (the Geum and Yeongsan) and the Jujin Stream, located on the southern shore of the inner bay. We observed relative reductions in the (La/Yb)_UCC value and REE content in the sediments from the mouth of the bay compared with those from Jujin Stream sediments. Confined to the middle tidal flat around the KH Line of Jujin Stream, the sediments, most enriched in LREEs but depleted in Eu, were distributed in August as strong Jujin Stream runs. Here, we suggest that an increase in LREE/HREE and decrease in MREE/LREE ratios can be used as a proxy to identify the Jujin Stream provenance in mixed riverine sediments and to trace Jujin Stream sediments within the Gomso Bay tidal flat, especially in the summer rainy season.  相似文献