보고서 정보
주관연구기관 |
한국지질자원연구원 Korea Institute of Geoscience and Mineral Resources |
연구책임자 |
고희재
|
참여연구자 |
권창우
,
박승익
,
박주언
,
기원서
|
보고서유형 | 최종보고서 |
발행국가 | 대한민국 |
언어 |
한국어
|
발행년월 | 2013-12 |
주관부처 |
미래창조과학부 KA |
사업 관리 기관 |
한국지질자원연구원 Korea Institute of Geoscience and Mineral Resources |
등록번호 |
TRKO201400005801 |
DB 구축일자 |
2014-06-07
|
초록
▼
1. 서 언
줄포도폭과 위도ㆍ하왕등도도폭(축척 1:50,000) 조사는 지식경제부 출연사업인 ‘지질도폭 조사 연구’의 일환으로 2012년부터 2013년까지 2년간에 걸쳐 수행되었다. 줄포도폭과 위도·하왕등도도폭 구역은 국립지리원에서 발간된 축적 1:50,000 부안지형도(도엽번호 NI 52-1-10)의 남부 2/3 면적과 인근 도서 지역인 위도(도엽번호 NI 52-1-09)와 모괴(도엽번호 NI 52-1-08) 지형도가 해당된다(그림 1-1). 동경좌표 기준으로, 줄포도폭은 동경 E126°30′00″∼E126°45′00″와 위
1. 서 언
줄포도폭과 위도ㆍ하왕등도도폭(축척 1:50,000) 조사는 지식경제부 출연사업인 ‘지질도폭 조사 연구’의 일환으로 2012년부터 2013년까지 2년간에 걸쳐 수행되었다. 줄포도폭과 위도·하왕등도도폭 구역은 국립지리원에서 발간된 축적 1:50,000 부안지형도(도엽번호 NI 52-1-10)의 남부 2/3 면적과 인근 도서 지역인 위도(도엽번호 NI 52-1-09)와 모괴(도엽번호 NI 52-1-08) 지형도가 해당된다(그림 1-1). 동경좌표 기준으로, 줄포도폭은 동경 E126°30′00″∼E126°45′00″와 위도 N35°30′00″∼N35°40′00″, 위도도폭은 동경 E126°14′00″∼E126°30′00″와 위도 N35°30′00″∼N35°40′00″에 해당한다. 하왕 등도도폭은 면적이 작은 수 개의 섬으로 구성되어 위도도폭에 포함하였다. 줄포, 위도·하왕등도도폭은 행정구역상으로 부안군(변산면, 계화면, 백산면, 주산면, 상서면, 보안면, 진서면, 줄포면, 위도면)이 대부분을 차지하며, 고창군(해리면, 심원면, 아산면, 부안면, 흥덕면, 성내면, 신림면)과 정읍시(영원면, 고부면, 소성면)의 일부 지역이 포함된다. 줄포도폭의 인접 지역에서 발간된 1:50,000 지질도는 남부의 고창도폭(이병주·이승렬, 2001)과 남동부의 신흥도폭(김정환 외, 1982)이며, 동부의 정읍도폭 및 북부의 부안도폭은 줄포, 위도·하왕등도도폭과 함께 금년에 발간되었다.
줄포, 위도·하왕등도도폭 구역은 지체구조적으로 옥천대의 남서부에 위치한다(그림 1-1). 줄포도폭 구역은 고원생대 편마암류를 중생대 쥬라기 화강암류가 넓게 관입하고 있다. 이들 화강암류는 전형적인 노년기 지층의 특징인 낮은 구릉지를 형성하고 그 상위에 백악기 화산암이 남부와 북부지역에 높은 산지를 이루며 원형 내지 타원형으로 분포하여 지형적으로 개략적인 시대별 지층구분이 가능하다. 남부에 분포하는 화산암은 고창도폭의 북부에 넓게 분포하는 선운사화산암의 북측 연장부이며, 북부 화산암은 부안도폭에서 줄포도폭으로 연장 분포하는 부안화산암이다. 위도·하왕등도도폭 구역은 중생대 백악기 화산암과 화강섬록암, 퇴적암 등으로 구성되어 험한 지형을 이루고 있다.
Abstract
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1. Introduction
The geological map of the Julpo and Wido·Hawangdeungdo sheets was mapped on a scale of 1:50,000 as one of the fundamental projects of the Korea Institute of Geoscience and Mineral Resources (KIGAM) during 2012∼2013, funded by the Ministry of Knowledge Economy of Korea.
The quad
1. Introduction
The geological map of the Julpo and Wido·Hawangdeungdo sheets was mapped on a scale of 1:50,000 as one of the fundamental projects of the Korea Institute of Geoscience and Mineral Resources (KIGAM) during 2012∼2013, funded by the Ministry of Knowledge Economy of Korea.
The quadrangles are bounded by the coordinates of longitude E126°30′00″∼E126°45′00″ and latitude N35°30′00″∼N35°40′00″ (Julpo Sheet), and longitude E126°14′00″∼E126°30′00″ and latitude N35°30′00″∼ N35°40′00″ (Wido·Hawangdeungdo Sheet), respectively.
The administrative districts of the quadrangle area include parts of Buan-gun, Gochang-gun and Jeongeup-si. The eastern area of the Julpo Sheet belongs to the southwestern margin of the NE-SW-trending Jurassic granitoid batholith. Cretaceous volcanic and volcanogenic sedimentary rocks occupy in the central and western area of the Julpo Sheet, and most of area of the Wido·Hawangdeungdo Sheet.
General topographic features of the Julpo Sheet are represented to the east by a flat plain formed by weathering of the Jurassic granitoid, and to the south and the north by mountainous highland formed by Cretaceous volcanic rocks. The northern and southern mountainous area divided by the Gomso Bay. The Wido·Hawangdeungdo Sheet is represented by hilly and mountainous. These topographic features are closely related to the geology of the sheets.
2. General Geology
The Julpo and Wido·Hawangdeungdo sheets consist largely the Jurassic granitoid, Cretaceous volcanic rocks and Quaternary alluvium with minor Ordovician tonalite, Paleoproterozoic gneiss, and Cretaceous granodiorite and dikes. Geological succession of the Julpo and Wido·Hawangdeungdo sheets is presented in Table 1.
2.1. Paleoproterozoic Gneiss
Paleoproterozoic gneiss, representing the oldest geological unit of the Jupo and Wido·Hawangdeungdo sheets, is unclassified gneiss and schist complex consisting largely of granitic gneiss, migmatitic gneiss, and banded gneiss together with schist and variable additions of granitic materials. From previous studies, the timing of metamorphism of gneiss and intrusion of old granitic materials was estimated to occur at ca. 1.87∼1.86 Ga, based on the latest SHRIMP U-Pb age of zircon.
2.2. Ordovician Foliated Tonalite
Ordovician tonalite occurs several Islands including Hyeongje Island in the Wido·Hawangdeungdo Sheet. It is not possible to establish stratigraphic relationship with other units because its occurrence is independent in Island. Tonalite shows porphyritic texture and was intruded by dike swarm of leucocratic granite with less than 1 m thickness. Intrusion age of tonalite is estimated to be 451.6±4.7 Ma by SHRIMP U-Pb zircon dating. Both tonalite and leucocratic granite were strongly deformed during Mid-Triassic Songrim orogeny. Metamorphic grade reaches epidote-amphibolite facies. Deformation features are characterized by rhombohedral-shaped plagioclase porphyroclasts, completely recrystallized quartz ribbon and subgrains of plagioclase and quartz.
2.3. Jurassic Granites
Jurassic Granites are the second large rock mass occurring in the Julpo Sheet, and belongs to a southwestern part of the Jurassic Daebo granite batholith running through northeast to southwest in the central part of Korea. Granites occur mainly in the eastern part of the Julpo Sheet, and consist of the Foliated Porphyritic Granite, Biotite Granite, Porphyritic Granite, and Fine-grained Biotite Granite in the ascending order. All the Jurassic granites are formed at the continental volcanic margin tectonic setting.
Foliated Porphyritic Granite, which is exposed mainly in the Gochang Sheet, occurs little as a xenolith of Biotite Granite in the boundary between the Julpo and Gochang sheets. Mineral assemblage of the rock is K-feldspar, plagioclase, quartz, hornblende and biotite with megacrysts of K-feldspar. Discontinuous and localized shear foliation is well observed. Biotite Granite is the largest rock mass among the Jurassic granites. Biotite Granite is massive and granular coarse-grained, and partly includes K-feldspar phenocysts. It is quite difficult to observe fresh outcrop because the rock was extremely weathered. However we can frequently observed granite texture in artificial slopes of lowland. The emplacement age of Biotite Granite is estimated to be 169.1~170.4 Ma by SHRIMP U-Pb zircon dating.
Porphyritic Granite occurs mainly in the eastern area of the Julpo Sheet and minor in the northeastern area of the Wido·Hawangdeungdo Sheet, intruding into both Biotite Granite and gneiss as stocks. It is classified as porphyry-bearing biotite granite in composition. The size of porphyry ranges from 2 to 4 cm, and the amount and size of it are variable depending upon localities of occurrence. Mineral assemblage of Porphyritic Granite is K-feldspar, plagioclase, quartz, biotite, sphene and allanite. Aggregate of chlorite, epidote and opaque minerals is considered to be pseudomorph of hornblende (?) as products of
alteration. The emplacement age of Porphyritic Granite is estimated to be 168.7~167.2 Ma by SHRIMP U-Pb zircon dating. Fine-grained Biotite Granite occurs as stock intruding into Biotite Granite, in the Mt Sugang of the southern central area of the Julpo Sheet. The rock is massive and fine-grained. Mineral assemblage is K-feldspar, plagioclase, quartz, biotite, sphene, opaque minerals. The emplacement age of Fine-grained Biotite Granite is estimated to be 166.4±1.4 Ma by SHRIMP U-Pb zircon dating.
2.4. Cretaceous Rocks
The Cretaceous Rocks are the largest rock mass occurring in the Julpo and Wido·Hawandeungdo sheets, and consist of Granite Porphyry, Volcanic rocks, Granodiorite and dikes. These occur in the northern part and southern central part of the Julpo Sheet and whole area of Wido·Hawangdeungdo Sheet. Cretaceous volcanic rocks can be divided into 4 kinds of volcanic unit such as Seonunsan, Buan, Wido, and Hawangdeungdo Volcanics based on lithology and localities of occurrence. All of volcanic rocks are formed at the continental volcanic margin tectonic setting.
Granite Porphyry occurs as small dike swarm in the southeastern part of the Wido Sheet. The width and intrusion direction are average 30 m, and N35°W, respectively. Quartz and feldspar phenocrysts of Granite Porphyry are mostly less than 0.5 cm, but a lot of euhedral K-feldspar porphyry reaching, at maximum, 4 cm, are frequently observed. SHRIMP U-Pb zircon dating give us age of 109.82±0.56 Ma.
Cretaceous volcanic bodies in the Julpo and Wido·Hawangdeungdo sheets occur regionally as an isolated topographic high land, compared to Proterozoic to Jurassic rocks occupying a topographic low land, and contain abundant volcanic to volcaniclastic and sedimentary successions. Because these successions are not directly correlated between the volcanic bodies, we are largely divided the volcanic bodies into four independent volcanics, named the Seonunsan Volcanics, Buan Volcanics, Wido Volcanics, and Hawangdeungdo Volcanics. Each volcanics can be subdivided into a number of lithological unit on the basis of rock type, eruption style (explosive vs. effusion), grain size, constitute mineral and lithic componentry and occurrence. The circular-shaped Seonunsan Volcanics, about 13 km in maximum diameter, refers to trachydacitic to rhyolitic volcanic to volcaniclastic successions in the southern part of the Julpo Sheet. It is composed of eleven lithological units: Gyeongsusan Tuff, Banam Tuff, Soyosan Tuff, Geomsanri Tuff, Yeongije Tuff, Seonunri Tuff, Sangdeungri Tuff, Gulchi Tuff, Meokbangje Tuff, Osanri Welded Tuff, Yongsanri Rhyolite, and Felsite in ascending order. The Gyeongsusan Tuff constitute the majority of the volcanics is exposed from west to central part of the volcanics and the other crops out mostly in the eastern part of the volcanics with tabular to pocket shapes. The strata of the successions mostly dip toward southeast on where located an inferred volcanic center. The SHRIMP U-Pb zircon ages of the Gyeongsusan Tuff and Yeongije Tuff represent 84.9±1.0 Ma and 86.5±1.7 Ma, respectively. The oval-shaped Buan Volcanics, about 20 km in maximum diameter, refers to rhyolitic volcanic to volcaniclastic and sedimentary successions in the northern part of the Julpo Sheet. It is composed of nine lithological units: Cheonmasan Tuff, Udongje Tuff, Seokpo Tuff, Gyeokpori Formation, Gomso Rhyolite, Yujeonge Tuff, Byeonsan Tuff, and Samyebong Rhyolite in ascending order. Each tuff unit is laterally persistent and the unit is easily identified by resedimented volcaniclastic deposits, which were intercalated along the unit boundary. The strata of the successions mostly dip toward north to northwest on where located an inferred volcanic center. The SHRIMP U-Pb zircon age of the Seokpo Tuff represents 88.7±2.0 Ma. The Wido Volcanics refers to volcanic to volcaniclastic and sedimentary successions in Wido Island and is composed of Daeri Andesite, Mangryeongbong Tuff, Beolgeumri Formation, Ttandalae Tuff, and Rhyolite in ascending order. The strata of the successions mostly dip toward northwest. The SHRIMP U-Pb zircon age of the Mangryeongbong Tuff represents 85.7±2.9 Ma. The Hawangdeungdo Volcanics in Hawangdeung Island is composed of the Jippungeum Andesite, Saenggeum Tuff, and Jaetmal Tuff in ascending order.
Granodiorite occurs independently in the Sangwangdeungdo. It is not clear stratigraphic relationship between granodiorite and the Hawangdeungdo Volcanics. Granodiorite is massive and fine-grained texture, and includes many of mafic enclave. In naked eye, hornblende and biotite, and cluster of mafic minerals are well observed.
Granodiorite consists of plagioclase, quartz, orthoclase, biotite, hornblende and minor sphene. Plagioclase has mostly euhedral and lath-shaped. Quartz shows space-filling growth between plagioclase and mafic minerals, indicating the latest growth of mineral. Intrusion age of granodiorite is estimated to be 85.03±0.89 Ma by SHRIMP U-Pb zircon dating. Dike rocks such as granite and quartz porphyries, acidic and intermediate dikes intruded along fractures and cracks of pre-stratigraphic units, in the timing of the late stage of volcanic eruption and intrusion of granodiorite.
2.5. Quaternary Sequences
Distribution of Quaternary alluvium is very large in the eastern area of the Julpo Sheet. It is composed of river deposits and weathered soil of biotite granite. Along the Gomso Bay, a lot of area was artificially reclaimed to use rice and salt fields.
3. Geochemistry
In TAS diagram, total alkali vs. silica (Na2O+K2O vs. SiO2), Ordovician foliated tonalite and Cretaceous granodiorite are plotted in diorite range, and Fine-grained Biotite Granite and Porphyritic Granite are plotted in granite range. All of the analyzed granites belong to calc-alkaline series in AFM diagram and volcanic arc granite range in Y vs. Nb and Y+Nb vs. Rb diagrams.
In TAS diagram, total alkali vs. Silica (Na2O+K2O vs. SiO2), all of the Sununsan volcanic rocks are plotted in rhyolite range, except the Gyeongsusan Tuff of trachyte-trachydacite range. All of the analyzed Seonunsan volcanic rocks belong to calc-alkaline series in AFM diagram, high-K calc-alkaline series in SiO2 vs. K2O diagram, and volcanic arc granite range in Y vs. Nb and Y+Nb vs. Rb diagrams.
The Cheonmasan Tuff, the Yeondong Tuff, the Udongje Tuff, the Seokpo Tuff, the Yujeongje Tuff, the Byeonsan Tuff, the Samyebong Rhyolite are plotted in the rhyolite range in TAS diagram, total alkali vs. silica (Na2O+K2O vs. SiO2). All of the analyzed Buan Volcanics belong to calc-alkaline series in AFM diagram, high-K calc-alkaline series in SiO2 vs. K2O diagram, and volcanic arc granite range in Y vs. Nb and Y+Nb vs. Rb diagrams.
4. Geological Structures
Most of the main geological structures in the Julpo and Wido·Hawangdeungdo sheets are developed in association with brittle deformation at shallow depth. They probably preserve significant clues to reconstruct the volcano-tectonic evolution of the unique volcanic bodies (Buan, Seonunsan and Wido Volcanics) within the quadrangles.
The most distinct structural feature of the volcanic bodies is cone or elliptical cone-like shape that is defined by concentric spatial distribution of bedding surfaces dipping toward the interior of the bodies. The unique geometry is recognized in the Seonunsan and Buan Volcanics including Gyeokpori Formation, and is due to passive tilting accompanying mechanical collapse of the volcanic bodies. In contrast with the Buan and Seonunsan Volcanics, the Wido Volcanics shows a gentle syncline fold with an axis sub-horizontally plunging toward SW.
The NNW-SSE, NNE-SSW, and NE-SW trending faults are also main deformational feature in the quadrangles. The orientations of the main faults are concordant with the predominant orientations of topographic lineaments. The subvertical faults are developed through multiple reactivations including right and left lateral sense as well as normal sense of movements. The normal sense of movement is likely to be occurred in association with collapse and subsidence of the volcanic bodies.
5. Geological History
Geological background such as occurrence, chronological and lithological relationship of units, geochemical characteristics indicates that rocks of the Julpo and Wido·Hawangdeungdo sheets built in Paleoproterozoic, Ordovician, Jurassic and Cretaceous. Geological history of the sheets began during the Paleoproterozoic, when the metasedimentary and igneous rocks were metamorphosed in 1.97∼1.96 Ga. After buildup of Paleoproterozoic gneiss, any kinds of geological event can not be recognized until the intrusion of Ordovician tonalite.
The timing of shear deformation of tonalite is not clear but it is considered to be product of the Mid-Triassic Songrim Orogeny. According to shift of tectonic setting in Mid Jurassic, huge mass of granites intruded into the survey area. Granites consist of Foliated Porphyritic Granite, Biotite Granite, Porphyritic Granite, Fine-grained Biotite Granite ranging from 170 to 166 Ma. Geochemical characteristics of granites are similar to the Jurassic Daebo Granite originated in the Arc Tectonic Setting. After intrusion of granites, the survey area was tectonically suspended until the intrusion of granite porphyry in age of 110 Ma.
The eastern margin of the Asian continent, including the Korean peninsula, underwent left-lateral wrench tectonics during the Cretaceous induced by oblique subduction of the Izanagi plate. This crustal deformation caused in the formation of sedimentary basins and volcanic activities in the peninsula. These syntectonic volcanisms are accompanied by complicated and numerous volcanic eruptions, and then a large volume of volcanic to volcaniclastic deposits resulted in the formation of specific volcanic architectures or bodies. The abundant volcanic to volcaniclastic deposits of the Cretaceous volcanics in the quadrangle area representing diverse volcanic activities (e.g., eruption type, size, volcanic feature, volume, material, etc.), and the resultant deposits are interpreted to have formed by the syntectonic volcanism in association with the Cretaceous subduction. An independent occurrence of the deposits of the volcanics in the different localities appears to reflect an existence of a number of isolated volcanic bodies. A cluster of active volcanoes in the quadrangle area should be interpreted as a site of active volcanic zone in the Korean peninsula during the Late Cretaceous.
Still under the tectonic influence of subducting Paleo-Pacific Plate, small stock of granodiorite and porphyries together with a series of intermediate to felsic dikes intruded in the survey area during the late-stage of volcanic eruption. After the Late Cretaceous, small Quaternary alluvium was deposited at the valley and around river and beach.
목차 Contents
- 표지 ... 1
- 목차 ... 7
- 1. 서 언 ... 9
- 2. 지 형 ... 11
- 3. 지질배경 및 층서 ... 14
- 4. 지질각론 ... 19
- 가. 고원생대 편마암 ... 19
- 나. 오도비스기 엽리상토날라이트 ... 20
- 다. 쥬라기 화성암 ... 24
- (1) 엽리상반상화강암 ... 24
- (2) 흑운모화강암 ... 25
- (3) 반상화강암 ... 27
- (4) 세립 흑운모화강암 ... 30
- 라. 백악기 화산암과 화성암 ... 32
- (1) 화강반암 ... 32
- (2) 선운산화산암 ... 33
- (가) 경수산응회암 ... 34
- (나) 반암응회암 ... 36
- (다) 소요산응회암 ... 37
- (라) 검산리응회암 ... 38
- (마) 연기제응회암 ... 39
- (바) 선운리응회암 ... 41
- (사) 상등리응회암 ... 41
- (아) 굴치응회암 ... 42
- (자) 먹방제응회암 ... 44
- (차) 오산리용결응회암 ... 45
- (카) 용산리유문암 ... 46
- (타) 규장암 ... 48
- (3) 부안화산암 ... 49
- (가) 천마산응회암 ... 49
- (나) 연동응회암 ... 51
- (다) 우동제응회암 ... 51
- (라) 석포응회암 ... 52
- (마) 격포리층 ... 54
- (바) 곰소유문암 ... 56
- (사) 유정재응회암 ... 57
- (아) 변산응회암 ... 58
- (자) 삼예봉유문암 ... 60
- (4) 위도화산암 ... 61
- (가) 대리안산암 ... 61
- (나) 망령봉응회암 ... 62
- (다) 벌금리층 ... 64
- (라) 딴달래응회암 ... 64
- (마) 유문암 ... 66
- (5) 하왕등도화산암 ... 66
- (가) 집푼금안산암 ... 66
- (나) 생금응회암 ... 67
- (다) 잿말응회암 ... 68
- (6) 화강섬록암 ... 69
- (7) 암맥류 ... 70
- 마. 제4기 충적층과 간척지 ... 71
- 5. 지구화학 ... 73
- 가. 화성암 ... 73
- 나. 선운산화산암 ... 75
- 다. 부안화산암 ... 77
- 6. 지질구조 ... 79
- 가. 개요 ... 79
- 나. 경동 및 습곡 ... 79
- 다. 단층 ... 83
- 라. 절리 ... 85
- 7. 지사 ... 86
- 참고문헌 ... 88
- SUMMARY ... 91
- 끝페이지 ... 106
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