• Journal of the Korean earth science society
• /
• v.27 no.6
• /
• pp.620-642
• /
• 2006

The Moho structure and its deformation in the southern part of the Korean Peninsula were estimated using gravity and topography data. Gravity signals from the upper and lower crust were separated using a filter that was computed from isostacy and elastic thickness. The result of this study shows three characteristic features of the Moho deformation. First, the Moho folding structure is parallel to SKTL (the South Korean Tectonic Line), which indicates positive association with the collision of the Yeongnam and Gyeonggi Massifs and repeated compression afterwards. In contrast, noticeable deformation of the Moho was not observed along the Imjingang Belt, which is interpreted as another continental collisional belt in the Korean Peninsula. Second, the Moho beneath the Gyeongsang Basin has remarkably risen; this seems to be the result from both the collisional compression and buoyancy caused by magmatic underplating. Third, the Moho deformation is shallowest in the east of the Taebaek Mountains and deepens toward the west, consistent with the topographic characteristic of the Korean Peninsula of "high east and low west". It can be interpreted as the results of the opening of the East Sea and Ulleung Basin. A tectonic explanation for this could be the ascent of the mantle induced by continental rifting and horizontal extension at the early stage of the opening of the East Sea. The Moho deformation model computed in this study correlates well with the earthquake distribution and crustal movement measured by GPS. We suggest that the compression along the SKTL is still exerted, consequently, the Moho deformation is active, although it may be weak.

• Development and Reproduction
• /
• v.21 no.1
• /
• pp.55-62
• /
• 2017

We used flowcytometry to ploidy verification after that investigate difference between diploid and spontaneous triploid through the truss dimension and classical dimension at crucian carp, Carassius auratus, crucian carp C. cuvieri and common carp, Cyprinus carpio collected from Hangang river, Hantangang river, Imjingang river, Geumgang river, Yeongsangang river and Nakdonggang river, Korea. There were significant differences among the three species for the truss dimensions anterior origin of dorsal fin $(2){\times}$ anterior origin of anal fin (5), $2{\times}$ anterior origin of pelvic fin (6), $2{\times}$ origin of pectoral fin (7), posterior origin of dorsal fin $(3){\times}5$, $3{\times}6$, and $3{\times}7$ (P<0.05). There were no significant differences among the three species in the truss dimensions dorsal fin length ($2{\times}9$) and eye diameter (ED)(P>0.05). On the other hand, there were no significant differences in the several classical dimensions of each species (P>0.05). Three classical dimensions, most anterior extension of the head $(1){\times}2$, $1{\times}6$ and $2{\times}$ most posterior scale in lateral line (4) did not differ between the C. auratus diploid and spontaneous triploid (P>0.05). Two classical dimensions, $1{\times}6$ and longest length between most anterior extension of the head and gill cover ($1{\times}8$) did not differ between the C. cuvieri diploid and spontaneous triploid (P>0.05). One classical dimensions, $1{\times}2$ did not differ between the common carp diploid and spontaneous triploid (P>0.05). There were significant differences in the each diploid and triploid species (P<0.05). These results suggest that the classification of each species and classification between diploid and spontaneous triploid morphometrical parameters used in this study are useful indices of morphometrical status in the each species from major river of Korea.

• Journal of the Korean Geophysical Society
• /
• v.9 no.3
• /
• pp.209-217
• /
• 2006

The major continental blocks in NE-Asia are the North China Block and the South China Blo, which have collided, starting from the Korean peninsula. The suture zone in NE China between two blocks is well defined from the QinIing-Dabie-Orogenic Belt to the Jiaodong (Sulu) Belt by the geological and geophysical interpretation. The discovery of high pressure metamorphic rocks in the Hongsung area of the Korean peninsula can be used to estimate the suture zone. This indicates that the suture zone in the Jiaodong Belt might be extended to Hongsung area. However, due to the lack of geological and geophysical data over the Yellow sea, the extension of the suture zone to the Korean peninsula across the Yellow Sea is obscure. To find out the tectonic relationship between NE China and the Korean peninsula it is necessary to complete U-ie homogeneous geophysical dataset of NE Asia, which can be provided by satellite observations. The CHAMP lithospheric magnetic field (MF3) and CHAMP-GRACE gravity field, combined with surface measured data, allow a much more accurate in-ference of tectonic structures than previously available. The CHAMP magnetic anomaly map reveals significant magnetic lows in the Yellow Sea near Nanjing and Hongsung, where are characterized by gravity highs on U-ie CHAMP-GRACE gravity anomaly map. To evaluate the depth and location of poten-tial field anomaly causative bodies, the Euler Deconvolution method is implemented. After comparing the two potential field solutions with the simplified geological map containing tectonic lines and the distribution of earthquakes epicenters, it is found that the derived structure boundaries of both are well coincident with the seismic activities as well as with the tectonic lineaments. The interpretation of the CHAMP satellite magnetic and GRACE satellite gravity datasets reveal two tectonic boundaries in U-ie Yellow Sea and the Korean peninsula, indicating U-ie norttiern and southern margins of the suture zone between the North China Block and the South China Block. The former is extended from the Jiaodong Belt in East China to the Imjingang Belt on the Korean peninsula, the later from Nanjing, East China, to Hongsung, the Korean peninsula. The tectonic movement in or near the suture zone might be responsible for the seismic activities in the western region of the Korean Peninsula and the development of the Yellow Sea sedimentary basin.

• The Journal of the Petrological Society of Korea
• /
• v.7 no.1
• /
• pp.15-26
• /
• 1998

The Dabie-Sulu ultra-high pressure metamorphic (UHPM) zone is commonly suggested to be a collisional belt between the Sino-Korea craton (North China craton) and Yangtze craton (Zhai and Cong, 1996). Two important questions in formulating the tectonic evolution of the northeast Asia are : (1) the boundary between the UHPM zone and the Sino-Korea craton in the Shandong peninsula and (2) the extension of this Chinese UHPM zone into the Korean peninsula. There have been different opinions on the boundary between UHPM zone and the Sino-Korea craton in the Shandong peninsula. For example, the boundary has been suggested to be the Tan-Lu fault (Bai et al., 1993; Wang and Cong, 1996), or Wulian-Rongcheng fault (Cao et al., 1990). Our recent study finds out new evidences, indicating that the possible boundary is the Kunyushan granitoid complex zone, which occurs along the Wulian-Muping fault. Our new evidences are : (1) the basic rocks west to the Kunyushan granitoid zone are high-pressure granulites rather than eclogites (Zhai, 1996) with their Sm-Nd isotopic ages of 1750 Ma and 2788 Ma, representing their retrograde metamorphic and petrogenetic ages, respectively (Li et al., 1997b); (2) the orthogneisses west to the Kunyushan granitoid zone yield 2600-2900 Ma zircon ages and 1600-2020 Ma Rb-Sr and chemical U-Th-total Pb ages, with no younger data (Enami et al., 1993; Ishizaka et al., 1994), having a typical characteristic for the early Precambrian rocks in the Sino-Korea craton; (3) the orthogneisses east to the Kunyushan granitoid zone have 110-320 Ma isotopic ages with a peak value of 180-230 Ma, showing a typical characteristic of metamorphic rocks in the UHPM zone; (4) the Kunyushan granitoid zone consists of numerous granitic bodies, stocks and veins, which have 1900-2000 Ma, 610-710 Ma and 124-180 Ma istotopic ages indicating a long and complicated evolution history of this granitoid zone. There are many lenses and enclosures of metamorphic rocks from the Sino-Korea craton and Sulu UHPM belt in the Kunyushan granitoid zone. Zhai et al. (1998) have defined the Kunyushan granitoid zone as the Jiaodong Boundary complex zone. Some geologists suggested that the UHPM zone extend eastward to the Korea peninsula (Yin and Nie, 1993; Wang and Cong, 1996) and possibly to the Imjingang belt (Chang, 1994; Ree et al., 1996). Unfortunately, there has not been a conclusive evidence indicating that UHPM rocks occur in the Korea peninsula. In this regard, it becomes more important to compare metamorphic rocks in the Shandong peninsula with those in northern and southern Korea peninsula.