• Journal of the Korean earth science society
• /
• v.27 no.2
• /
• pp.236-246
• /
• 2006

On the basis of field observation, geology of the footprints site consists of the Kwanghaeak Basalt, unnamed strata, Songaksan Tuff, Hamori Formation, and Sand Dune, in ascending order at the Hamori-Songaksan area and the Kwanghaeak Basalt, the hominid footprints-bearing strata, and Dune Sand are consisted in ascending order at the Sagaeri area. According to the designation that the Hamori Formation overlies the Songaksan Tuff, age dating results, and geologic sequence observed in the field, the strata containing hominid footprints are not correlated with the Hamori Formation but the unnamed strata, though the strata are shown as the Hamori Formation in the geologic map. It seems to be more reasonable that the geologic age of the footprints-bearing strata is thought to be around ca 15,000 yrs B.P. according to the results of $^{14}C$ dating.

• The Journal of the Petrological Society of Korea
• /
• v.10 no.1
• /
• pp.13-26
• /
• 2001

Songaksan volcano, which occurs as a monogenetic volcano on the southwestern promontory of Hallasan shield volcano, is composed of tuff ring, cinder cone, lava pond and cinder conelet complex on wide basalt plateau. Except for an influx of external quartz xenocrysts in the tuff ring. Totally the volcano ranges from trachyandesite to trachybasalt in petrography and chemical compositions, which confirm the continuum between the evolved and primitive compositions widely occurring in the Jeju volcanic system. Chemical data for the volcano show quantitative compositional variation from the lower to the upper part of the volcanic sequences. The continuous compositional variations generally define a compositionally zoned magma storage. The chemical data suggest that the compositiona1 donations might have resulted from the fractional crystallization of a parental alkali magma. As result, the Songaksan volcano initially tapped the lop of the zoned magma storage and subsequently erupted successively more primitive magma.

• Proceedings of the Mineralogical Society of Korea Conference
• /
• 2001.06a
• /
• pp.71-74
• /
• 2001

• Proceedings of the Petrological Society of Korea Conference
• /
• 2001.06a
• /
• pp.71-74
• /
• 2001

• Proceedings of the Petrological Society of Korea Conference
• /
• 2000.05a
• /
• pp.18-18
• /
• 2000

• Korean Journal of Mineralogy and Petrology
• /
• v.36 no.4
• /
• pp.365-376
• /
• 2023

Songaksan, formed about 3800 year ago, is one of the tuff rings in the Jeju Island. Mantle xenoliths, spinel peridotites, are enclosed in the Songaksan Trachybasalt. The spinel peridotites are less than 2 cm in size and are composed of olivine, orthopyroxene, clinopyroxene, and spinel. The uniform compositions of the minerals from core to rim indicate that equilibrium was reached in the spinel peridotites before these were enclosed in the host magma. The spinel peridotites originated at depths between 55 and 60 km with equilibrium temperatures ranging from 915 to 968℃. The spinel peridotites from Songaksan reveal porphyroclastic texture with a lot of neoblast minerals. Olivines display strong kink banding, indicating that the upper mantle of Songaksan has been deformed. The spinel peridotites from Songaksan have undergone about 5~7% fractional melting, and cryptic metasomatism by an silicate melt. The period of entrainment and transport of the spinel peridotites in the host magma is about 15 days.

• The Korean Journal of Malacology
• /
• v.18 no.1
• /
• pp.41-52
• /
• 2002

This study was performed to know the vertical distribution pattern and community structure of intertidal invertebrates at 9 sampling stations near Songacksan area located in Jeju Island from June 2000 to May, 2001. A total of 104 benthic invertebrate species was recorded during the survey period and it was composed of 50 families, 25 orders, 12 classes and 6 phyla. Among them, the most highest species richness was observed in the mollusks comprising 66.3% (69 species) and the next one in the arthropods showing 16.3% (17 species). Species diversity was largely different depending on their vertical distribution, revealing much higher in the lower intertidal zone than in the middle or upper zone, while there were no distinct differences between sampling stations. The dominant species were Nodilittorina exigua, Littorina brevicula, Pollicipes mitella mitella and Nerita japonica in the upper zone, Monodonta neritoides, Lunella coronata coreensis and Nerita japonica in the middle zone and Notoacmea schrenckii, Omphalius nigerimus, Purpura clavigera and Chlorostoma argyrostoma lishckei in the lower zone. The macrobenthic fauna surveyed could be divided into two groups based on their species similarities between sampling stations but their differences were not distinctive.

• Journal of Korean Society for Geospatial Information Science
• /
• v.19 no.3
• /
• pp.33-40
• /
• 2011

This paper presents the prediction and evaluation of landslide using LRA(logistic regression analysis) and ANN (Artificial Neural Network) methods. In order to assess the landslide, we selected Sarabong, Byeoldobong area and Mt. Song-ak in Jeju Island. Five factors which affect the landslide were selected as: slope angle, elevation, porosity, dry density, permeability. So as to predict and evaluate the landslide, firstly the weight value of each factor was analyzed by LRA(logistic regression analysis) and ANN(Artificial Neural Network) methods. Then we got two prediction maps using AcrView software through GIS(Geographic Information System) method. The comparative analysis reveals that the slope angle and porosity play important roles in landslide. Prediction map generated by LRA method is more accurate than ANN method in Jeju. From the prediction map, we found that the most dangerous area is distributed around the road and path.

• The Journal of the Petrological Society of Korea
• /
• v.25 no.1
• /
• pp.69-83
• /
• 2016

Radiocarbon and OSL ages of three monogenetic volcanoes inferred to be the last volcanoes on Jeju Island, Korea were determined to identify a volcano described in historical records. The results show that the ages of those volcanoes are roughly <3.8 ka (Songaksan), >4.5 ka (Biyangdo), and <6~7 ka (Ilchulbong). Though our efforts to make a positive match between historical records and volcano-chronological dating were not successful, we make a new suggestion in this paper that two historical records of volcanic activity in 1002 and 1007 A.D. could be interpreted to be the sequential volcanic events from a single monogenetic volcano. In addition, based on a volcanological reinterpretation of historical records, we infer that the volcano described therein is most likely Mt. Songaksan, in Daejeongeup, which had early phreatomagmatic and late magmatic activities after 3.8 ka ago. Furthermore, considering the geopolitical relationship between the Goryeo Dynasty and the Tamna Kingdom, in addition with the culture of the era, this study sheds new light on the possibility that there is a time gap between the actual eruptions and the historical recording of them by ancient people.

• Journal of the Korean earth science society
• /
• v.24 no.3
• /
• pp.172-180
• /
• 2003

Geologic field survey is very important for the high school students who take the courses of earth science under the 7th earth science curriculum, however actually it is very difficult for the students to survey in the field because of long time and distance, and expenses. To overcome these difficulties, this study focused on developing the web contents and teaching-learning materials for virtual geologic field survey of the Songaksan and Jisagae area, Jeju island. The developed web contents were placed into three parts; main manu, sub manu and contents to help the learners flow-chart of the program easily. To overcome the weakness of existing textual web materials, some movable images and worksheets were provided for the learners, and the web contents were designed for the learners to experience as similar as the geologic field survey may let them do.