• Journal of the Korean Geographical Society
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• v.38 no.4
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• pp.490-504
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• 2003

The existence of coastal terraces, HH(High higher) surfaces found at Gampo of southeast coast and at Jeongdongjin of the central east coast were confirmed at Jjgyeong-Ri, the areal border between Gyeongjuand Ulsan city on the southeast coast of Korea Peninsula. Especially this study reports HH JK-surface located on the 155m a.s.l, which is the highest altitude among the ancient shorelines of the coastal terraces in Korea. The HH surfaces on the study area are classified into HH JK at 155m, HH I at 140m and HH II at 115m, and each formation stage is related to MIS 17(720∼690ka BP), MIS 15(630∼560ka BP) and MIS 13(510∼480ka BP) respectively. The HH-surfaces remain to be larger than those of H- and L-surfaces. The reason is caused by the unique factors of the coastal geology and morphology on the study area during the formation stage. And also the areal difference by the magnitude of upheaval doesn't exist from north to south because the altitude system of ancient shoreline on each coastal terrace is same along the east coast. The upheaval rate of the eastern coastal areas was measured in the relation to the ancient shoreline and formation stage among the coastal terraces such as HH JK-, HH I-, HH II, H I- and H II surface, and was almost same as 0.23mm/y.

• Economic and Environmental Geology
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• v.17 no.3
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• pp.215-230
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• 1984

Petrological, paleomagnetic, geomorphological and structural studies on the southern part of, so called, Chugaryeong rift valley, have been carried out in order to clarify the nature of the rift valley. Three stages of volcanic activities characterized by Jijangbong acidic volcanic rocks and tholeiitic and andesitic basalt of Cretaceous age(?), and Jongok Quaternary olivine basalt occurred along the Dongducheon fault line. Jijangbong acidic volcanic rocks distributed in the central part of the studied area consist of rhyodacite, acidic tuff and tuff breccia, which are bounded by Dongsong fault on the east and Daegwangri fault on the west. The Jongok basalt differs from those of Ulrung and Jeju islands in mineralogy, chemical composition and differentiation. Jongok basalt distributed along the Hantan river dilineates the vesicles curved toward downstream direction and increment of numbers and thickness of lava flow toward upstream direction. These facts suggest that lava flowed from upstream side of the river. Rectangular drainage patterns also support the presence of the Dongducheon, Pocheon, Wangsukcheon and Kyonggang faults which were previously known. LANDSAT image, however, does not show any lineaments which could be counted as a graben or rift valley. Displacement of Precambrian quartzite and Jurassic Daedong supergroup along the southwestern extension of the Dongducheon fault shows the right lateral movement. The Paleomagnetic study of the tholeiitic and andesitic basalts from Baegeuri, Jangtanri and Tonghyeonri located at 2. 3km east, 0km east, and 1.5km west of Dongducheon fault respectively shows that their VGP(Virtual Geomagnetic Pole) being to intermediate geomagnetic field of short duration which suggests that they formed in almost same period. Mean VGP of Jongok basalt is located 82.4N and 80.6E. This is in good coincidence with worldwide VGP of Plio-Pleistocene indicating that Jongok basalt was extruded during Plio-Pleistocene epoch, and suggesting that the studied area has been tectonically stable since then. From the present study, the tectonic episode of the region is concluded as following three stages. 1. The 1st period is worked by the Daebo orogeny of Jurassic during which granodiorite was intruded in Precambrian basement. 2. The 2nd period is the time when right lateral strike-slip fault of NNE-SSW direction was formed probably during late Cretaceous to Paleogene and the Jijangbong acidic volcanic rocks and the older basalts were extruded. 3. The 3rd period is the time when the fault was rejuvenated during Pliocene or Pleistocene accompanied by the eruption of Jongok basalt. As a conclusion, geologic structure of the studied area is rather fault line valley than graben or rift valley, which is formed by differential erosion along the Dongducheon fault suggesting a continuation of the Sikhote-Alin fault. The volcanic rocks including the Jijangbong acidic rocks, tholeiitic-andesitic basalt and olivine basalt are associated with this fault line.

• Economic and Environmental Geology
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• v.49 no.4
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• pp.291-299
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• 2016

This study examined stratigraphic research containing extreme climate event during Quaternary period in Saban-ri, Haeri-myeon, Gochang by constructing 3D topographic model and 3D geological model. As a result of 3D topographic model and subsurface geological model, the geology of study area accumulated bedrock, Pleistocene series, and Holocene series chronologically. Most of the study area consist of bedrock on basement and Holocene series on upper layer. Additionally, Pleistocene series are presented as lens-shaped deposit on eastern part, and wedge-shaped deposit on northeastern part. Holocene layers consist of sand and clay-silt layer deposited sequentially where implies fluvial deposits on transgression environment. Distinctively, Pleistocene clayey silt layer and Holocene sand layer on eastern are observed as pond shape deposits that are considered as storm-related deposits originated from overwash system caused by extreme paleoclimate.

• The Korean Journal of Quaternary Research
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• v.6 no.1
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• pp.1-11
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• 1992

The reconstruction of the vegetational and environmental history of the Korean peninsula by the use of various fossil floral data from the Carboniferous period to the Pre-Holocene is reviewed. Though the oldest plant fossil in Korea (Neuropteris) dates back to the Carboniferous period, the first appearance of many of the present-day floristic genera indeed dates back to the Oligocene (c. 40 to 20 million years B.P.), and includes many thermophilous genera. The presence of thermophilous genera in the Oligocene at up to four degrees north of their present distributional limits implies that the climate of the Oligocene was warmer than that of today. The occurrence of similar thermophilous floristic element at up to six degrees north of their present range during the Middle Miocene suggests a maximum northward expansion of warmth-loving evergreen broadleaved vegetation for, recent Korean vegetation history. The continued occurrence of numerous present-day genera since the Oligocene period indicates a long-term stability of Korean vegetation, along with minor fluctuations within it. The admixture of evergreen coniferous plants and deciduous breadleaved plants, however, indicates a probable temperate climate for much of the Middle Pleistocene. There are couple of evidences which are indicative of an early-stage anthropogenic disturbance of natural vegetation during the Middle Pleistocene of Korea. The presence of cold-episodes during the Upper Pleistocene caused a general expansion of deciduous plants and cryophilous evergreen coniferous, plants. It is likely that the maximum southward expansion of cryophilous arctic-alpine and alpine floras in Korea occured during the penultimate glacial period. The disappearance of some cryophilous genera from 10,000 years B.P. marks the continued climatic amelioration since then, along with minor climatic fluctuations during the Holocene period.

• Economic and Environmental Geology
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• v.52 no.5
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• pp.409-425
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• 2019

Marine terraces, a step-like landform, are important geologic markers that provide tectonic information during the Quaternary Period. Marine terraces are well developed along all coastlines(East, West, and South) of the Korean Peninsula, those along the East coastline are the most distinctive. The marine terraces of the East coastline are classified into 4-6 flights that are several meters or several tens of meters above the present sea level. It is believed that these terraces, except for the lowest one, were formed in the middle Pleistocene. In the base of the OSL age dating results and Blake excursion events of magnetostratigraphy, the $2^{nd}$ and $3^{rd}$ terraces are correlated to the last interglacial stage. Considering the marine terraces linked to a sea-level curve of the Pleistocene, it is thought that regional tectonic movements have uplifted the East coastal area since the middle Pleistocene. Besides, former shorelines of each terrace have varied elevations from Gangreung to Busan bay, which can be divided into four regions, namely, Gangreung-Yonghanri(I), Homikot-Najung(II), Najung-Bangeojin(III), and Waesung-Busan Bay(IV). The former shorelines of each terrace at both Gangreung-Yonghanri(I) and Najung-Bangeojin(III) are higher than those in the other two regions, due to block movements by regional faults such as the Ocheon Fault or its subsidiaries, the Gampo Lineament and Ulsan Fault. Uplift rate of the East coast ranges from 0.2 m/ky to 0.3 m/ky, but each region shows different uplift rate.

• Journal of the speleological society of Korea
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• v.42 no.2
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• pp.17-28
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• 1995

THE K-AR METHOD of age determination is commonly used to date rocks from Pleistocene volcanoes in Japan (e.g. Kaneoka et al. 1980, Itaya et al. 1984, Shimizu et al. 1988, Itaya et al. 1989). However. there are still many problems with K-Ar dating of the young volcanic rocks, as reviewed by Itaya and Nagao (1988).(omitted)

• Proceedings of the Korean Quaternary Association Conference
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• 2005.06a
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• pp.37-41
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• 2005

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.3-6
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• 2003

Southwest Hokkaido (Sapporo-Iwanai district) in the Northeast Japan arc (Fig. 1) is one of the best places to test the correlation among tectonic regime, stress field, magmatic style and hydrothermal mineralization. This paper reviews the Miocene to Pleistocene tectonic framework, geology, magmatic style and stress field of southwest Hokkaido, and correlates them with different types of deposits (Kuroko, epithermal base-metal and precious-metal). (omitted)

• The Korean Journal of Quaternary Research
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• v.18 no.2 s.23
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• pp.3-3
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• 2004

One short core with length of 146cm(HB-107, at coordinates of $N51^{\circ}$11'37.5";$E100^{\circ}$24'45.6", from 229m water depth was subject of the present study. The sub-samples of the core were analyzed for the water contents (WC%), biogenic silica, identification of the main phases, grain size distribution, geochemistry and some physical properties of sediment(Wet density and Magnetic susceptibility) with aims of recording palaeo-environmental changes in Northem Mongolia. The evaluation of the geochemical and mineralogical proxies on palaeo-climated and palaeo-environmental changes are based on comparison to the behvior of biogenic silica through core, as later one had been showed itself, as good indicator of the climate and environmental fluctuation. Age model of the investigating core based on previously C 14 dated core HB105 taken from the central part of the Hobsgol Lake and the result had been published elsewhere. The core consists of two litological varieties : upper diatomaceous silt, lower clay. According to the age model the upper diatomaceous silt formed during the Holocene, lower caly-during the late Pleistocene glacial period. The geochemistry and phase identification analysis on the core samples are resulted in determining main minerals that form the bottom sediments and their geochemistry. The main include quartz, felspar, muscovite, clinochlore, amphibole and carbonate phase(dolomite and calcite). Through the core not only occur the relative quantitative changes of the main phases, but also happen that the carbonate phase completely disappear in diatomaceous silt. This is believed to be related to the lake water salinity changes, which occurred during the trassition period from Pleistocene glacial-to the Holocene interglacial. These abrupt changes of the mineralogy have been clearly traced in geochemistry of sediments, specially in calcium concentration, which is high in lower clay and low in upper diatomaceous silt. That means, geochemistry and mineralogy of the bottom sediments can be used as proxy data on palaeo-climate and palaeo-environmental changes.

• Journal of Environmental Impact Assessment
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• v.15 no.5
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• pp.323-337
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• 2006

This work discussed the species composition, phylogeny, spatio-temporal distribution, ecology and natural history of North Korean Pinaceae or pine tree family, which seems to be important to maintain nature and ecosystem in the Korean Peninsula. Out of five genera and sixteen species of Pinaceae of the Korean Peninsula, North Korea contains four genera and eleven species of Pinaceae, including Pinus densilflora, P. koraiensis, P. pumila, Picea jezoensis, P. koraiensis, P. koraiensis var. koraiensis, P. pungsanensis, Larix gmelini, L. gmelinii var. olgensis, Abies holophylla and A. nephrolepis. In terms of phylogeny Pinus is closely related to Picea, and followed by Larix. Abies is close to Tsuga which only occur at Ullung Island. Distributional pattern of North Korean Pinaceae can be classified into four types; three species of nation-wide montane type i.e., Pinus densilflora, P. koraiensis and Abies holophylla, four species of central and northern subalpine type, i.e., Pinus pumila, Picea koraiensis, Larix gmelini and Abies nephrolepis, one nation-wide subalpine type, Picea jezoensis, and three species disjunctive to north type, i.e., Picea koraiensis var. koraiensis, P. pungsanensis, and Larix gmelinii var. olgensis. Pinaceae species occurring on the alpine and subalpine belts of North Korea, such as Pinus koraiensis, P. pumila, Picea jezoensis, P. koraiensis, P. koraiensis var. koraiensis, P. pungsanensis, Larix gmelini, L. gmelinii var. olgensis and A. nephrolepis are considered as the glacial descendant from the boreal region. Those species might have migrated from the north during the Pleistocene glacial epochs in search of favourable condition, and since the Holocene period they survived on the hostile alpine and subalpine environments, in which they are more competitive than warmth-tolerant temperate vegetation. Certain species, such as Picea pungsanensis, is segregated on the isolated mountains since the Pleistocene period, and forced to adapt to local environment, and eventually became an endemic species of North Korea. Recent rapid global warming trend especially in northern high mountains of North Korea could cause an unfavourable environment for the survival of cold-tolerant Pinaceae of the alpine and subalpine belts. Pinus densiflora, which is occurring on the montane belt might faced with difficulties due to both the deforestation and the outbreak of insect-borne disease, such as Bursaphelenchus xylophilus.