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이학석사 학위논문

Carbon Isotope, Nitrogen Isotope,

and Clay Mineral Compositions

of the Korean Middle Ordovician

Successions and Their

Paleoceanographic Implications

한국 중기 오르도비스기의 탄소 동위원소,

질소 동위원소, 점토광물 조성과

그 고해양학적 의미

2017 년 2월

서울대학교 대학원

지구환경과학부

방 선 화

ii

Abstract

Carbon Isotope, Nitrogen

Isotope and Clay Mineral

Compositions of the Korean

Middle Ordovician Successions

and Their Paleoceanographic

Implications

Sunhwa Bang

School of Earth and Environmental Sciences

The Graduate School

Seoul National University

The middle Ordovician successions from the Taebaek and

Yeongwol sections, Gangwon Province, Korea, were studied

with carbon isotope, nitrogen isotope, and clay-mineral

compositions to observe the middle Darriwilian carbon

isotope excursion (MDICE) event and its paleoceanographic

conditions.

The carbon isotope value of the Taebaek section shows a

iii

gradual shift in the upper Maggol Formation, overlain by a

large negative shift of -6.79‰ until the middle part of the

Jigunsan Formation, and then to a heavier trend with broad

positive peaks that are continued to the upper Jigunsan

Formation and the middle Duwibong Formation as recognized

to be MDICE. The Yeongwol sections of the Middle

Ordovician Yeongheung Formation show higher carbon

isotope values and the lower part of the Yeongwol1 and the

whole Yeongwol2 section are correlated to MDICE with three

positive peaks.

The nitrogen isotope compositions are heavier during the

early stage of MDICE event in both the Taebaek and the

Yeongwol1 sections. The clay minerals shift to kaolinite-

enriched compositions concurrently with a stronger signal in

the Taebaek section. The nitrogen isotope and clay mineral

compositions are interpreted as a result of epeiric-sea

denitrification enhanced by seawater stratification due to

heavy precipitation on the nearby land, during the early

MDICE interval.

The documentation of the MDICE event in the study

suggests that global MDICE records have a close temporal

background and a common point of carbon isotope peaks.

This study also proposes regional paleoceanographic

conditions prevailed in middle Ordovician epeiric sea during

the MDICE event.

Keyword : Middle Ordovician, MDICE, Carbon Isotope,

Nitrogen Isotope, Clay Mineral, Paleoceanography

iv

Student number : 2014-22427

v

TABLE OF CONTENTS

ABSTRACT ............................................................................. ii

TABLE OF CONTENTS .......................................................... v

LIST OF FIGURES ................................................................. vii

LIST OF TABLES ................................................................... ix

1. INTRODUCTION ................................................................. 1

2. GEOLOGICAL SETTING ..................................................... 9 2.1 3rd order sequence stratigraphy ................................................ 9

2.2 Biostratigraphy ............................................................................... 9

2.3 Studied Area.................................................................................. 11

3. MATERIAL AND METHODS ............................................. 18 3.1 Sample information ...................................................................... 18

3.2 Carbon and oxygen isotope and carbon contents ............... 18

3.3 Nitrogen isotope, content and clay mineral contents .......... 22

4. RESULTS .......................................................................... 23 4.1 Taebaeksan Basin, Seokgaejae Section(Taebaek) ............. 23

4.1.1 Carbon and Oxygen isotope ...................................... 23

4.1.2 Nitrogen isotope and TIC, TOC, TN contents........... 24

4.1.3 Clay mineral contents ...................................................... 24

4.2 Yeongwol Basin, Namgyo Section(Yeongwol1) .................. 36


4.2.2 Nitrogen isotope and TIC, TOC, TN contents ......... 36

4.2.3 Clay mineral contents ............................................... 37

4.3 Yeongwol Basin, Soggol section(Yeongwol2) ...................... 47


4.3.2 TIC, TOC, TN contents ............................................. 47

5. DISCUSSION ..................................................................... 63 5.1 Regional chemostratigraphy ...................................................... 63

5.2 Environmental condition ............................................................ 65

5.2.1 Seawater stratification .............................................. 65

vi

5.2.2 Weathering input ....................................................... 66

5.2.3 Regional paleoceanography on MDICE .................... 68

5.3 Implications for global paleo-environment distribution ..... 74

5.3.1 Global correlation ...................................................... 74

5.3.2 Implications for global oceanography ....................... 79

6. SUMMARY AND CONCLUSIONS ...................................... 81

REFERENCES ........................................................................ 83

ABSTRACT (IN KOREAN) ................................................... 92

ACKNOWLEDGEMENT (IN KOREAN) ................................. 94

vii

LIST OF FIGURES

Fig 1-1. Large-scale δ13C curve of the latest Precambrian

and the Phanerozoic period ..................................................... 4

Fig 1-2. Ordovician global environment signals .................... 7

Fig 1-3. Globally synthesized Ordovician carbon isotope

curve and biostratigraphy ......................................................... 8

Fig 2-1. Correlations between Taebaek and Yeongwol by

biostratigraphy, sequence stratigraphy ................................. 13

Fig 2-2. Recent version of middle Ordovician Peleogeographic

map dotted with MDICE studied areas .................................. 14

Fig 2-3. Location of the sampling sites ................................ 15

Fig 2-4. Stratigraphy of middle Ordovician succession of

Taebaek and Yeongwol ........................................................... 16

Fig 2-5. Logging map with biostratigraphy and sequence

stratigraphy of studied sections ............................................. 17

Fig 3-1. Outcrop features of Taebaek section ..................... 20

Fig 3-2. Outcrop features of Yeongwol sections ................. 21

Fig 4-1. Middle Ordovician stable isotope data(δ13Ccarb and

δ15N) and clay mineral composition of Taebaek section .... 26

Fig 4-2. Middle Ordovician Total Nitrogen content(TN), total

organic carbon content(TOC), total inorganic carbon

content(TIC), CN ratio of Taebaek section .......................... 27

Fig 4-3. Cross plots of oxygen isotope versus carbon

isotope(A,B,C) and Total inorganic carbon content versus

total nitrogen content(D, E, F) ............................................... 28

Fig 4-4. Middle Ordovician stable isotope data(δ13Ccarb

viii

and δ15N) and clay mineral composition of Yeongwol1 section

.................................................................................................. 38

Fig 4-5. Middle Ordovician Total Nitrogen content(TN), total

organic carbon content(TOC), total inorganic carbon

content(TIC), CN ratio of Yeongwol1 section ...................... 39

Fig 4-6. Illite crystallinity values of the Taebaek and

Yeongwol1 section, Relationship between illite crystallinity

Kubler index, Weaver index and Intensity ratio ................... 40

Fig 4-7. Middle Ordovician stable isotope data(δ13Ccarb) and

Total Nitrogen content(TN), total organic carbon

content(TOC), total inorganic carbon content(TIC), CN ratio

of Yeongwol2 section .............................................................. 48

Fig 5-1. Correlations between regional carbon isotope

chemostratigraphy of Taebaek, Yeongwol1, Yeongwol2

section ...................................................................................... 64

Fig 5-2. Detailed paleoceanographic model of regional carbon

isotope excursion of epeiric sea, with timing of oceanic anoxia,

sea water stratification, heavy precipitation, in case of

Taebaek and Yeongwol section .............................................. 73

Fig 5-3. Rearrange of biostratigraphy, carbon isotope

chemostratigraphy, and lithostratigraphy of previous studied

paleocontinents ........................................................................ 77

Fig 5-4. Correlation of biostratigraphy, carbon isotope

chemostratigraphy, and lithostratigraphy between MDICE

records ..................................................................................... 78

ix

LIST OF TABLES

Table 4-1. Total nitrogen(TN), Total carbon(TC), Total inorganic carbon(TIC), Total organic carbon(TOC), CN ratio and carbon

isotope, oxygen isotope, nitrogen isotope with delta of Taebael

section. ...................................................................................... 29


isotope, oxygen isotope, nitrogen isotope with delta of Yeongwol1

section ....................................................................................... 41


isotope, oxygen isotope, nitrogen isotope with delta of Yeongwol2

section ....................................................................................... 49

Table 4-4. XRD data with KI(Kuber index), major peaks(001, 003), WI(Weaver index), Ir(Intensity ratio) and clay mineral

contents of Taebaek section ...................................................... 52

Table 4-5. XRD data with KI(Kuber index), major peaks(001, 003), WI(Weaver index), Ir(Intensity ratio) of Yeongwol1 section

and clay mineral contents of Yeongwol1 section ........................ 58

1

CHAPTER 1. INTRODUCTION

The environmental changes in the Earth’s history associated with large

extinction events, have been reported with the corresponding fluctuations in

isotopic values (Fig 1-1). The ocean plays a role in regulating atmospheric

carbon dioxide concentration and the dissolved carbonate forms in seawater

through the interaction with the atmosphere, the marine environmental

conditions like oxygen saturation and acidity has been sensitive to the

changes in the system (Berner, 1990; Kump and Arthur, 1999; Sundquist and

Visser, 2003; Maslin and Swann, 2006). For example, in the Ordovician time,

the Steptoean positive isotopic carbon excursion (SPICE) appears at the

Cambrian-Ordovician boundary with rapid sea level fall and large species

extinction(Gill et al., 2007). There is also interval known as Hirnantian

positive isotopic carbon excursion (HICE) with gradual sea level drop and

cooling before the Ordovician-Silurian boundary, and huge ice age with more

than 85% of marine life extinction occurred at the end of the Ordovician

(Fanton and Holmden, 2007; Saltzman et al., 2004). As such, mass-extinctions

and glacial periods during geological time have very distinctive global signals

of positive or negative carbon isotopic values, and give strong suggestions

for the relationship between global carbon cycling and rapid global

environmental changes (Fig 1-1).

The critical regulating factor of seawater dissolved inorganic carbon (DIC) is

the carbon exchange between the atmosphere and the ocean (Berner, 1990;

Kump and Arthur, 1999; Maslin and Swann, 2006; Sundquist and Visser, 2003).

In the process of dissolved organic carbon (DOC) synthesis by marine

organisms, relatively light 12C is selectively consumed by biological

assimilation, which makes stable carbon isotope composition (δ13C) of

seawater DIC more positive than organic matter. The oceanic DIC is closely

related to the surface and deep seawater circulation, topographic location,

2

and composition of the incoming weathering (Algeo et al., 2016; Diz et al.,

2009; Gruber et al., 1999; Immenhauser et al., 2002; Kroopnick, 1985; Kump

et al., 1999; Kump et al., 2005; Lynch-Stieglitz, 2006; Patterson and Walter,

1994; Sarmiento and Gruber, 2006).

However, in spite of regional differences, the carbon isotope variation

curves from carbonate platform and carbonate mound sediments show

largely similarity to those those from global open oceans in geological scale,

making the carbon isotope stratigraphy a useful tool to study global carbon

cycle (Amodio et al., 2008; Ferreri et al., 1997; Mutti et al., 2006). Even in

the Ordovician, the period of widely distributed epeiric seas with regional

isotopic characters, records can be still globally correlatable with distinctive

global carbon isotope excursions (Gill et al., 2007; Patzkowsky et al., 1997).

In the comparison between SPICE (around +4‰ excursion; Gill et al., 2007)

and the HICE (around +7‰ excursion; Kump and Arthur, 1999), the Middle

Ordovician time experienced relatively small variations in carbon isotope

composition, and therefore was considered as a time of chemically stable

with little fluctuations (Fig 1-1). Still questions remain about the mechanism

causing the major Ordovician changes, the Middle Ordovician has been

studied much lesser than the Early or Late Ordovician period. However,

Ainsaar et al., (2001) reported a globally identifiable carbon isotope

abnormality now known as MDICE (middle Darriwilian isotopic carbon

excursions) for the first time, the first recognized carbon isotope excursion

of the Middle Ordovician (Fig 1-2).

Consequently, some researchers seriously studied the existence of the

MDICE during the past decade (Ainsaar et al., 2010; Ainsaar et al., 2015;

Albanesi et al., 2013; Bauert et al., 2014; Calner et al., 2010; Diamond, 2013;

Kaljo et al., 2007; Ma et al., 2015; Munnecke et al., 2011; Schmitz et al.,

2010; Sial et al., 2013). The excursion is usually found before or within the

Pygodus serra conodont biozone and the Middle Ordovician

chronostratigraphic Darriwilian Dw3 stage, and show +1 to +5‰ increase

carbon isotope ratio. The magnitude of fluctuation is relatively smaller than

3

the events like the SPICE or HICE, but some researchers argued that this

event gave global oxygenation to the Middle Ordovician ocean and that

chemical instability was made by that cycle changes acted between great

biodiversification events and strontium isotope drop (Fig 1-2). Some also has

been raised that the MDICE as the start line of the Ordovician chemical

cycle instability and deep ocean conveyor belt activation (Rasmussen et al.,

2016), and considered the sustained environmental change from this interval

in association with the large extinction accompanied by the Great Hirnantian

Ice age (Zhang et al., 2010). Recent sulfur isotope studies agreed with the

view on the ocean circulation during the MDICE period (Kah et al., 2015;

Young et al., 2015), but the detailed oceanic mechanisms of this event are

still not clear. Thus, interpretations on carbon cycle change in regional

epeiric sea and comparison with global MDICE records can provide a

valuable paleoceanographic model.

4

Fig. 1-1. Large-scale δ

13C curve of the latest Precambrian and the

Phanerozoic period. Red lines mark the period boundary. SPICE: Steptoean

positive isotopic carbon excursion; MDICE: Middle Darriwilian isotopic carbon

excursion; GICE: Guttenberg isotopic carbon excursion; HICE: Hirnantian

isotopic carbon excursion; P‒T Extinction: Permian-Triassic extinction; OAEs:

Oceanic anoxic event; PETM: Paleocene‒Eocene Thermal Maximum).

(modified from Halverson et al., 2005; Veizer et al., 1999; Cited in Bang

and Lee, 2016)

5

The most widely used Ordovician global carbon isotope stratigraphy is

Bergström et al. (2009), which is a compilation of records from various

regions, presented at different resolutions in Fig 1-2 and Fig 1-3. These

authors used a method to reestablish a locally analyzed carbon isotope curve

through the Ordovician and the data that constitute the overall curve

originated from different parts of each period. The Tremadocian‒Dapingian

record is from the study conducted in Argentina (Buggisch et al., 2003) and

the Darriwilian‒Sandbian, Hirnantian records are shown in the studies from

the eastern part of the North American continent (Bergström et al., 2007;

Berry et al., 2002; Finney et al., 1999; Kaljo et al., 2007), in the integrated

carbon isotope curve as shown in Fig 1-2, the MDICE occur in the middle to

late Darriwilian. However, the timing of the occurrence of local MDICE

seems to differ according to the biostratigraphic time, as shown in Kaljo et

al. (2007), one of the studies constituting the Middle Ordovician part of this

integrated stratigraphy.

Nevertheless, if the studied strata include the middle Darriwilian, the parts

where the carbon isotope ratio (δ13Ccarb value) curve has broad and large

positive peaks are called MDICE, and the variation ranges from +0.5‰ to +5

‰ (Zhang and Munnecke, 2010; Ainsaar et al., 2015). Regional differences in

carbon isotope fluctuations are related to the significant regional

characteristics of the Middle Ordovician sedimentation environments

(Patterson and Walter, 1994; Holmden et al., 1998; Immenhauser et al., 2002).

Despite the wide distribution over different continents, the similarity of the

widespread positive anomalies in the Middle Ordovician period has been

noted by the researchers (Ainsaar et al., 2001; Bauert et al., 2014; Calner et

al., 2014; Lehnert et al., 2014).

One of the hallmarks of the Middle Ordovician, the drop point of strontium

isotope ratio (87Sr/

86Sr) was also reported from the Nevada section in western

North America (Young et al., 2009; Fig 1-2). This point is known as the

largest drop of 87Sr/

86Sr in the Phanerozoic Eon, where the value falls from

0.7090 to a 0.7076. The ratio of strontium isotope is usually interpreted as

6

the reflection of the silicate mineral weathering influx, and based on the

relatively high value of the continental weathering product (0.711) and the

lower value of basaltic rock weathering product from central (0.702), which

can indicate dominance of continental weathering or oceanic basalt

weathering (Berner, 2006). Inferring fron the drop in strontium isotope ratio

in the Middle Ordovician period, the amount of weathering of the basaltic

rock was increased, and a large amount of atmospheric carbon dioxide would

have been consumed in the production of secondary mineral (Hansen et al.,

1983; Cuffely et al., 1995). Therefore, Young et al. (2009) speculated that

the interval of strontium drop could be the trigger for large climatic

changes such as late Ordovician glaciation, but previous sea surface

temperature measurements, however, indicate that stable climate of the

Middle Ordovician has not been changed greatly at this time(Trotter et al.,

2008) (Fig 1-2). Recently, Rasmussen et al. (2016) reported regional cooling,

but they have pointed activation of the deep ocean circulation currents as

the cooling factor. Therefore, more questions are being raised about the

Ordovician climate system.

As a result, the presence of global transgression trends, increased

weathering of sulfur-bearing minerals, and increased surface productivity in

shallow marine environments in the Middle Ordovician have been inferred

(Haq and Schutter, 2008; Kah et al., 2015; Young et al., 2015; Rasmussen et

al., 2016), but there are only minor considerations on the fundamental

environmental mechanism of the MDICE event. The aim of this study is to

report the MDICE record from the Sino-Korean basin, correlate regional

carbon isotope chemostratigraphy with the MDICE features, and suggest new

mechanisms for the Korean basins located in an equatorial epeiric sea during

the Middle Ordovician.

7

Fig 1-2. The Ordovician global environment signals

(modified from Sepkoski, 1996; Haq and Schutter, 2008; Trotter et al., 2008; Young et al., 2009; Bergström et al.,

2009; Chern et al., 2013; Lehnert et al., 2014; Cited in Bang and Lee, 2016)

8

Fig 1-3. Globally synthesized Ordovician carbon isotope curve and biostratigraphy. LDNICE: Lower Darriwilian

negative isotopic carbon excursion; MDICE: Middle Darriwilian isotopic carbon excursion (modified from Saltzman,

2005; Bergstöm et al., 2009; Ainsaar et al., 2010; Cooper et al., 2012 and Lehnert et al., 2014; Cited in Bang and

Lee, 2016)

9

CHAPTER 2. GEOLOGICAL SETTING

2.1 3rd-order sequence stratigraphy

According to Kwon et al., (2006), the sequence stratigraphy of the Taebaek

area shows subareal exposure with rapid sea level drop at top of the Maggol

Formation. After that sequence boundary, sea level continued to rise during

the deposition of the Jigunsan and Duwibong formations. Other regional

studies supported this view on the Middle Ordovician stratigraphy of the

Taebaek area (Choi et al., 2004; Kwon et al., 2006).

In the Yeongwol area, Yoo and Lee (1997) interpreted the Yeongwol1

(Namgyo) and Yeongwol2 (Soggol) sections as the middle sequence cycle

order of the Yeongheung Formation, According to their interpretation, the

present studied sections belong to the transgression and highstand state.

Kwon (2012) correlated the transgression in the lower part of the Yeongwol1

to the Jigunsan and Duwibong formations of Taebaek area. Upper part of

the Yeongwol1 succession following the missing part in the middle

correspond to the time after the deposition of the Duwibong Formation (Fig

2-1 and Fig 2-5).

2.2 Biostratigraphy

Conodont biozone of the Jigunsan Formation is classified as Eoplacognathus

suecicus−E.jigunsanensis zone and can be correlated to the E. suecicus

biozone of the North Atlantic lineage zone (Bergström, 1977; Lee and Lee,

1986). Korean conodont biozone defined the interval from the bottom of the

Duwibong Formation as the Plectodina onychodonta Zone, which correspond

to the early-middle part of the North Atlantic Pygodus serra Zone. The

10

middle Yeongheung Formation was classified as the Plectodina onychodonta

Zone, as Duwibong Formation (Lee, 1989). The upper part of the

Yeongheung Formation includes the Rhipidognathus neimenguensis‒Oulodus

orengonia‒Erismodus typus‒Tasmanognathus careyi Zone, which suggest that

the uppermost part of the Yeongheung Formation may contain lower

Sandbian (Lee, 1989).

Trilobite biostratigraphy of the Taebaek and the Yeongwol area reported by

Choi and Chough, (2005), correlated to Dolerobasilicus zone of the Jigunsan

Formation to the Keyserapsis zone of the Yeonghueng Formation. It also

suggest that the Yeongheung Formation may biostratigraphically contain the

Maggol, Jigunsan, Duwibong formations within its range (Fig 2-4).

11

2.3 Studied Area

The Middle Ordovician succession of the South Korea was deposited in an

epeiric sea of west equatorial peri-Gondwana. It is exposed in the

Seokgaejae section in the eastern part of the Taebaeksan Basin and distal

Yeongwol section in the western part of the basin (Fig 2-4). As shown in

Fig 2-2, most of the previous study areas are located within 30°S from the

Middle Ordovician equator. The records from the Taebaek and the Yeongwol

area will provide another equatorial carbon isotope chemostratigraphy. A

continuous succession of the lower Paleozoic is called the Joseon Supergroup,

which consists of the Taebaek group in the eastern part of the Taebaeksan

Basin (the Jangsan, Myeonsan, Myobong, Daegi, Sesong, Hwajeol, Dongjeom,

Dumugol, Maggol, Jigunsan and Duwibong Formations in ascending order)

Choi et al., 2004; Fig 2-3 and Fig 2-4). In the Taebaek area, the Jigunsan

and Duwibong formations are belong to the Middle Ordovician Darriwilian

stage(Choi et al., 2004; Cocks and Torsvik, 2004; Lee et al., 2016; Zhange et

al., 2010; Zhen et al., 2015), and are interpreted as deposited in epeiric-sea

located in western Gondwana (Lee et al., 2016; Jin et al., 2013; Fig 2-1 and

Fig 2-2).

Among the Sangdong subgroup (Dongjeom, Dumugol, Maggol, Jigunsan and

Duwibong Formation), chronostratigraphic, conodont biostratigraphic scales of

the Jigunsan and Duwibong formations coincide with previous MDICE studies

(Fig 2-4). The Maggol Formation shows sabkha-type dolomitization in its

upper parts. The following Jigunsan Formation has 40 to 60 m vertical

thickness with difference between sections, and in Seokgaejae section has

the thickness of 39 m consisting of mainly black shale and interbedded black

shale with light gray limestone, or limestone nodule. Often the lower part

shows pyrite particles and is correlated to the North Atlantic conodont

Eoplacognathus variables and E. suecicus zones, which is succeeded by the

Pygodus serra Zone of the Duwibong Formation. The Duwibong Formation is

unconformably overlain by the Carboniferous−Triassic Pyeongan Supergroup

12

and consists mainly of massive light-gray limestone, mostly wackestone to

grainstone. The vertical thickness of the Duwibong Formation is 60 to 80 m

in the Taebaeksan Basin, Due to the large fault in the middle part, however,

the studied Duwibong Formation is about 40m thick from the Jigunsan-

Duwibong Formation boundary (Fig 2-5).

The Yeongwol basin has five lithostratigraphic units: the Sambangsan,

Machari, Wagok, Mungok, and Yeongheung formations. The Yeongheung

Formation is the Middle Ordovician carbonates overlying the Mungok

Formation with vertical thickness around 400m (Choi, 1993). It experienced

deep burial with syn-depositional dolomitization and its depositional

environment is interpreted as shallow marine to tidal flat (Woo and Choi,

1993; Yoo and Lee, 1993). The conodont biostratigraphy of the Yeongheung

Formation is dated as middle Arenigian to middle Caradocian (Lee, 1989),

which covers 4 lithostratigraphic unit of the Taebaek basin (Upper Dumugol,

Maggol, Jigunsan and over Duwibong Formation). But the sampled

Yeongwol1(Namgyo) and Yeongwol2(Soggol) sections, are correlated to the

middle sequence order of the Yeongheung Formation (Yoo and Lee, 1997;

Fig 2-1 and Fig 2-5).

13

Fig 2-1. Correlation between the Taebaek and the Yeongwol based on biostratigraphy, sequence stratigraphy on

previous studies(modified from Lee and Lee, 1986; Lee, 1989; Lee, 2004; Yoo and Lee, 1997; Kwon, 2012)

14

Fig 2-2. The global Middle Ordovician paleogeographic map dotted with MDICE studied areas(red points). Studied

section data are modified from Kaljo et al. (2007), Ainsaar et al. (2010), Munnecke et al. (2011), Thompson and

Kah (2012), Albanesi et al. (2013), Sial et al. (2013), Lehnert et al. (2014), Ainsaar et al. (2015) and Zhang and

Munnecke (2015). Paleomap data modified from Scotese and Golonka (1997), Torsvik and Cocks (2013), Yao et al.

(2015) and Lee et al. (2016), Cited in Bang and Lee, 2016

15

Fig 2-3. Location of the sampling sites (modified from Lee and Lee, 1986; Yoo and Lee, 1997; Lee, 2016)

16

Fig 2-4. Stratigraphy of the Middle Ordovician succession of the Taebaek

and the Yeongwol

(modified from Cheong, 1969; Lee, 1987; Lee, 2004; Lee et al., 2012; Lee et

al., 2016)

17

Fig 2-5. Logging map with biostratigraphy and sequence stratigraphy of studied sections

(modified after Lee and Lee, 1986; Lee, 1990; Yoo and Lee, 1997; Choi et al., 2004; Choi and Chough, 2005;

Kwon et al., 2006)

18

CHAPTER 3. MATERIAL AND METHODS

3.1 Sample information

From the bottom of Seokgaejae, Namgyo and Soggol section, samples were

collected in 2m or 1m interval. 117 samples collected from the Seokgaejae

section (Fig 3-1) cover the stratigraphic succession of 93 m in vertical

thickness. 87 samples were collected for the 99.2m thick of middle-upper

Yeongheung Formation at the Yeongwol1 (Namgyo) section, and 40 samples

were collected from the 44.1m thick middle Yeongheung Formation in the

Yeongwol2 (Soggol) section (Fig 3-2). Total 244 samples were cut to 1 cm

cubes and slabs, to eliminate the parts with fossil and vein, and then were

powdered by using an agate mortar and a dental drill.

3.2 Carbon and Oxygen isotope and carbon contents

The micritic powdered samples were reacted with 10% Phosphoric acid

(H3PO4) for 10 to 50 minutes following the common acid bath method, and

carbon isotope analysis was carried out by using IsoPrime model mass

spectrometers at the Korea Basic Science Institute and the Stable Isotope

Laboratory of the University of Michigan. Isotope data were reported in δ

notation, with δ13Ccarb to the PDB scale, which has the reproducibility of ±

0.1‰.(1σ)

Additional rock powder samples were analyzed for carbon contents at the

Korea Polar Research Institute and Korea Institute of Ocean Science

Technology. Total carbon(TC), total organic carbon(TOC) contents were

analyzed by the elemental analyzer FlashEA 1112, and total inorganic

carbon(TIC) contents were analyzed by the CM5015 UIC CO2 coulometer

which went through the process of measuring the carbon dioxide gas

19

generated by the reaction of 20mg powdered samples with 10% Perchloric

acid (HClO4) at 50℃ for 10 minute.

20

Fig 3-1. Outcrop features of Taebaek section: red dotted line as Jigunsan-Duwibong Formation

boundary(A, B) , mud layer startline of Maggol-Jigunsan Formation boundary(C), thick

interbedded shale and limestone of upper Jigunsan Formation

21

Fig 3-2. Outcrop features of Yeongwol sections: Bioturbated dolomudstone of middle

Yeongheung Formation(A, Yeongwol1 section), Cryptalgalaminate of middle-upper Yeongheung

Formation(B, Yeongwol1 section), Bioturbated dolomudstone of upper Yeongheung Formation(C,

Yeongwol1 section), overview of Yeongwol2 outcrop(D)

22

3.3 Nitrogen isotope, contents and clay mineral contents

The micritic powdered samples were analyzed by IsoPrime elemental

analyzer coupled with a stable isotope ratio mass spectrometer at the

National Instrumentation Center for Environmental Management in Seoul

National University, to measure total nitrogen (TN) content and nitrogen

isotope composition. The Nitrogen isotope data were reported in in δ

notation, with δ15N to the air scale.

To determine clay mineral contents and their alteration, bulk insoluble-

residue samples were prepared with 2N HCl solution for carbonate

elimination, and size separated with centrifuge method to make oriented

samples(

23

CHAPTER 4. RESULTS

Carbon isotope and oxygen isotope results are presented for all sections.

Oxygen isotope values were only used to test relationships with carbon

isotope values. The Taebaek section and the Yeongwol1 section have clay

mineral ratio and nitrogen isotope results for environmental interpretation.

The Yeongwol2 (Soggol) section was excluded in nitrogen isotope analysis,

due to the low nitrogen content.

4.1 Taebaeksan basin, Taebaek (Seokgaejae) section

4.1.1 Carbon and Oxygen isotope

The carbon isotope values from the Taebaek section ranges from -0.21‰

to -6.79‰ and show large fluctuation than that of the other two sections.

Carbon isotope values from the top of the Maggol Formation (0 to 9 m

interval) record maximum +1.66‰ positive shift from -1.87‰ to -0.21‰ and

is followed by a large negative peak of -6.79‰ at 25.7m. The positive

isotopic shift from -6.79‰ to -1.8‰ in 25.7-27 m interval record the first

positive excursion in the middle Darriwilian. After the second positive peak

with a maximum of -0.66‰ the third positive peak records the maximum of

-0.34‰. After these three positive peaks, the carbon isotope value stands

around -2‰ for while (53-61 m interval), but slowly increases to the high

peak of -0.25‰ at 78m(Fig 4-1, Table 4-1). The lowest carbon isotope value

interval coincides with the lowest TIC interval(10-25 m), but the relationship

between these two-factors is weak with low R2 value(0.0214; Table 4-1).

Oxygen isotope ratio is cross-ploted with carbon isotope ratio, which show

strong positive relationship in the cross-plot in case of isotopic alteration by

weathering. Fig 4-3 shows minor relationship between the two factors, which

24

indicates there might be some post-depositional alteration, but it would not

have been strong enough to eliminate the original signal.

4.1.2 Nitrogen isotope and TIC, TOC, TN contents

The nitrogen isotope values from this section range from -2.2‰ to +12.18

‰ and the most negative shift occurs in 9m to the 12m interval in which

δ15N decrease from +9.4‰ to -2.2‰. After this excursion, nitrogen isotope

value slightly increases to around +3.53‰ until the 30m point, but from the

31m point they drastically become heavier and show maximum +9.29‰ peak

in 39m. This positive excursion in nitrogen isotope value changes to negative

shift, and they stay below +2‰ with weak fluctuations after the 49m point

(Fig 4-1, Table 4-1).

Total nitrogen (TN), total inorganic carbon (TIC), total organic carbon (TOC),

and CN ratio of TB section show a significant difference between intervals.

At the boundary between the Maggol Formation and the Jigunsan formations,

TN and TOC become very rich, and TIC drops from 11.5% to 5.6%,

indicating the change from the lime-/dolostone to calcareous shale. 4 m to

40 m interval have low TN(but mostly >0.01%) with relatively high TOC

value, so CN ratio have extremely high points and one of them not shown

in the graph (the point have at 4m point). After the 40m point, TIC

recovers from 7% to 10.5% with the appearance of the limestone, and TN

(>0.04) and TOC (>0.3) are not so low in this interval (Fig 4-2).

4.1.3 Clay mineral contents

The extracted insoluble residue powder and oriented samples(

25

appears in 17 m to 21 m interval. Illite ratio is very restrained in 22 m to

48m interval, which is dominated by kaolinite. The kaolinite richness ends

after 43 m point with rich chlorite, and the upper part shows the dominance

of illite and some kaolinite peaks(e.g. 63 m, 73 m point; Fig 4-1).

The IC and IR values of the Taebaek section clay samples mostly plot on

epizone area (

26

Fig 4-1. The stable isotope data(δ13Ccarb and δ

15N) and clay mineral composition of the Taebaek section. 3 point

moving average smoothed line(red and blue plot), raw data(gray line), the average value(vertical dotted line) in

the isotopic graph. Illite or smectite content(blue area), kaolinite(green area), chlorite(red area) in clay mineral(%)

graph.

27

Fig 4-2. The total nitrogen(TN), total organic carbon(TOC), total inorganic carbon(TIC), CN ratio of the Taebaek

section

28

Fig 4-3. Cross-plots of oxygen isotope versus carbon isotope(A, B, C) and Total organic carbon(TOC) versus

total nitrogen(TN) content(D,E,F) of studied sections

29

Table 4-1. Total nitrogen(TN), total carbon(TC), total inorganic carbon(TIC), total organic carbon(TOC), CN ratio

and carbon isotope, oxygen isotope, nitrogen isotope with delta(δ) notation of the Taebaek section

Name Height(m) TN(%) TC(%) TIC(%) TOC(%) CN ratio δ

13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

M1 0 0.020409 11.44702 11.1038 0.34322 16.81724 -1.74 -13.44 6.16

M2 1 0.009323 11.7855 11.0541 0.731397 78.44846 -1.87 -12.89 6.4

M3 2 0.007906 11.99535 11.5917 0.403654 51.05414 -1.15 -11.33 6.63

M4 3 0.011941 12.05906 11.5878 0.47126 39.46665 -1.27 -11.97 6.29

M5 4 0.011517 12.18706 11.7362 0.450861 39.14675 -0.44 -11.32 12.18

M6 5 0.024349 12.52742 12.5897 11.8298 485.852 -0.21 -8.06 8.4

M7 6 0.012637 11.83732 11.3654 0.471922 37.3442 -0.58 -11.47 9.86

M8 7 0.008999 11.98381 11.5661 0.417709 46.41623 -0.74 -11.06 5.52

M9 8 0.006837 12.09064 11.6804 0.410238 60.00415 -1.15 -9.46 8.57

M10 9 0.031273 12.05795 11.5707 0.487251 15.58039 -0.85 -10.27 9.4

J2-1 9.6 0.033177 7.104591 5.6046 1.499991 45.21135 -3.7 -11.14 4.75

25-45 10 0.105 6.809 4.18 2.629 25.0381 -1.937225192 -13.24045546 -0.66

J1 12 0.08 8.102 6.2494 1.853 23.1575 -1.444575262 -14.55275522 -2.2

J2-2 12.6 0.02029 8.831006 7.7377 1.093 53.88459 -1.83 -14.49 7

J2 14 0.075 7.1064 4.9676 2.139 28.51747 -1.538275089 -14.78888232 -1.6

J2-3 14.6 0.037182 7.244235 5.2928 1.951 52.48371 -1.79 -14.1 4.66

J3 15 0.063 7.526 5.772 1.754 27.84127 -1.885847962 -14.7198083 1.38

J2-4 15.5 0.038533 7.112853 5.2195 1.893 49.13579 -1.67 -13.85 4.3

J4 16 0.041 7.473 6.4579 1.015 24.75854 -2.2406 -14.8875 2.19

30

Table 4-1. (Continued)


13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

J2-5 16.5 0.023432 8.03808 6.8247 1.213 51.78304 -1.95 -14.25 6.24

J5 17 0.067 2.364 1.4995 0.865 12.90299 -1.318462512 -14.40448043 3.68

J6 18 0.057 2.336 1.5109 0.825 14.47544 -2.112841964 -15.06366668 2.09

J2-6 18.5 0.027742 4.367423 3.7634 0.604 21.7725 -2.69 -13.4 6.02

J7 19 0.063 1.834 1.2842 0.55 8.726984 -2.750423449 -16.24381615 3.33

J2-7 19.5 0.038 5.284 4.882 0.402 10.57895 -3.03 -14.36 6.2

J8 20 0.057 1.249 0.8663 0.383 6.714035 -2.722894832 -16.55567115 1.28

J9 21 0.048 1.287 0.9708 0.316 6.5875 -2.567790278 -17.81104314 1.41

J2-8 21.5 0.0215 5.4262 5.1896 0.237 11.00836 -2.8 -14.24 6.84

J10 22 0.041 0.764 0.5193 0.245 5.968293 -3.01495502 -16.73243224 0.33

J22 23 0.029 4.596 4.2119 0.384 13.24483 -4.474867671 -15.24318425 3.27

J2-9 23.2 0.0189 5.79 5.5369 0.253 13.37004 -5.17 -16.7 4.62

J23 24 0.04 0.93 0.7432 0.187 4.67 -3.106428319 -15.33332488 2.15

J24 25 0.036 0.459 0.2869 0.172 4.780556 -3.796676098 -15.10043794 1.17

J2-10 25.7 0.0093 7.5639 6.6502 0.914 98.49798 -6.79 -15.73 6.37

J25 26 0.036 0.234 0.10399 0.13 3.611389 -3.553016521 -14.55342862 2.34

J26 27 0.035 0.808 0.6718 0.136 3.891429 -1.74514413 -14.81668534 -0.38

J27 28 0.029 3.79 2.6308 1.159 39.97241 -2.841064831 -14.74036021 3.85

31


13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

J28 29 0.028 2.939 2.7142 0.225 8.028571 -2.81807 -14.7277 2.08

J2-11 29.5 0.022521 2.617702 2.5039 0.114 5.053055 -4.53 -14.32 6.02

J29 30 0.037 0.318 0.195 0.123 3.324324 -3.321422531 -13.76266577 -0.48

J2-12 30.5 0.018618 4.713374 4.4704 0.243 13.05047 -2.19 -13.87 4.74

J30 31 0.029 0.925 0.747 0.178 6.137931 -4.093003602 -12.7844746 2.52

J2-13 31.5 0.020175 3.333043 3.1953 0.138 6.827324 -3.34 -14.19 3.07

J31 32 0.022 5.049 4.6018 0.447 20.32727 -2.046357174 -13.81705775 5.77

J32 33 0.037 1.567 1.4694 0.098 2.637838 -3.267717251 -11.71619201 3.56

J2-14 33.5 0.01663 0.745508 0.6194 0.126 7.583206 -4.27 -13.79 3.9

J33 34 0.03 1.915 1.7113 0.204 6.79 -3.231465692 -14.09287886 3.44

J2-15 34.5 0.02453 3.084315 2.8726 0.212 8.630887 -2.45 -13.72 4.45

J34 35 0.03 3.649 3.2619 0.387 12.90333 -1.84521573 -14.14229422 4.92

J35 36 0.03 2.0168 1.8016 0.215 7.17473 -1.785845579 -13.35798505 3.07

J2-16 36.5 0.013931 5.385119 5.1848 0.2 14.37979 -2.47 -13.41 4.84

J36 37 0.023 6.1776 5.6737 0.504 21.90809 -0.878134178 -12.82353561 6.39

J2-17 37.5 0.008582 10.78673 10.2545 0.532 62.02023 -1.25 -12.73 9.41

J37 38 0.02 4.596 4.2091 0.387 19.345 -1.248435108 -12.98926916 6.43

J38 39 0.02 6.649 6.1522 0.497 24.84 -1.38199 -12.7834 9.29


32


13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

J2-18 39.5 0.005271 11.28254 10.8699 0.413 78.29193 -0.66 -11.73 10.78

J39 40 0.028 6.797 5.1928 1.604 57.29286 -0.95435 -12.5638 4.94

J40 41 0.032 6.574 6.1116 0.462 14.45 -0.93927784 -12.25288159 3.63

J2-19 41.8 0.009077 11.05137 10.4983 0.553 60.92857 -0.99 -11.36 7.77

J41 42 0.019 7.324 6.7553 0.569 29.93158 -2.4225 -11.0003 7.87

J2-20 42.8 0.01116 10.27703 10.1116 0.165 14.8225 -0.88 -11.65 4.23

J42 43 0.028 7.274 6.8703 0.404 14.41786 -1.421737382 -12.60521029 5.11

J2-21 43.8 0.010866 10.05527 9.3172 0.738 67.92324 -1.17 -11.57 9.15

J43 44 0.034 4.488 4.2071 0.281 8.261765 -3.441131938 -10.2884733 3.66

J2-22 44.8 0.020482 1.594012 1.3056 0.288 14.08149 -1.4 -12.63 4.08

J44 45 0.02 5.353 5.0379 0.315 15.755 -3.0162255 -10.33381817 8.1

J2-23 45.8 0.017686 4.123714 3.8778 0.246 13.90436 -1.61 -12.28 3.3

J45 46 0.019 6.677 6.3666 0.31 16.33684 -1.88202 -12.7754 8.3

J46 47 0.02 5.067 4.6525 0.415 20.725 -1.25716 -12.7382 8.07

J2-24 47.8 0.015898 7.623532 7.294 0.33 20.72805 -1.62 -11.49 4.31

J47 48 0.032 2.9551 2.6979 0.257 8.038694 -1.195910275 -12.91330808 1.66

J2-25 48.8 0.034 8.869 8.4965 0.373 10.95588 -0.9 -12.41 6.89

D1 49 0.067 11.35 10.9019 0.451 6.732836 -0.702722599 -11.6 1.85


33


13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

D2 50 0.057 11.55 11.0756 0.472 8.287719 -0.339799552 -11.5 3.45

D3 51 0.063 11.48 10.9792 0.502 7.965079 -0.4905 -11.2 2.55

D4 52 0.072 11.18 10.8597 0.321 4.4625 -1.996213689 -9.9 2.21

D5 53 0.082 7.7705 7.0871 0.683 8.334149 -2.186847753 -11.4 -1.32

D6 54 0.062 10.57 9.8648 0.702 11.32581 -1.8746 -10.4 2.14

D7 55 0.069 9.174 8.1834 0.991 14.35652 -2.312272665 -10.7 1.86

D8 56 0.062 9.9184 9.4872 0.431 6.954236 -1.850491177 -10.4 3.14

D9 57 0.071 8.4879 7.8136 0.674 9.497502 -1.940038041 -10.3 -0.31

D10 58 0.061 10.9 10.2599 0.636 10.42787 -1.526207943 -10.4 2.53

D11 59 0.067 10.39 9.8767 0.515 7.691045 -2.3068 -10 3.11

D12 60 0.076 9.399 8.7796 0.619 8.15 -2.232118195 -10.1 -0.31

D13 61 0.059 10.07 9.5277 0.537 9.10678 -1.123956664 -8.4 0.01

D14 62 0.068 11.32 10.4828 0.841 12.37059 -1.28749691 -9.5 2.03

D15 63 0.066 10.88 10.1311 0.745 11.28636 -1.873133985 -9.9 0.37

D16 64 0.064 10.52 9.8978 0.623 9.7375 -1.799074847 -9.5 2.39

D17 65 0.063 11.46 10.8367 0.624 9.909524 -1.46191131 -9.4 1.04

D18 66 0.077 11.38 10.5522 0.829 10.76364 -1.583847732 -9.4 -0.71

D19 67 0.045 11.36 10.6887 0.673 14.96222 -1.9768 -9.2 0.81


34


13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

D20 68 0.061 11.52 10.9074 0.608 9.960656 -1.282492343 -9.7 -0.72

D21 69 0.073 10.84 10.04 0.798 10.93151 -1.039392918 -10.3 2.89

D22 70 0.061 10.32 10.0025 0.315 5.155738 -1.181578228 -9.5 0.29

D23 71 0.079 10.0738 9.5435 0.53 6.713227 -1.56506001 -9.7 0.14

D24 72 0.067 10.6 10.1951 0.4 5.968657 -1.177827824 -9.8 1.91

D25 73 0.065 10.99 10.6328 0.353 5.433846 -0.942203027 -9.7 2.27

D26 74 0.084 11.48 10.6076 0.871 10.37381 -1.112022744 -9.8 1.34

D27 75 0.056 10.93 10.3846 0.546 9.757143 -0.782925406 -9.5 0.05

D28 76 0.081 11.07 10.4295 0.64 7.895062 -0.6751 -9.3 0.97

D29 77 0.079 11.61 10.7867 0.822 10.40886 -0.540032677 -8.8 2.15

D30 78 0.063 11.47 10.9379 0.533 8.461905 -0.2514 -9.2 4.35

D31 79 0.068 11.6 10.9351 0.669 9.836765 -0.480152321 -9.3 0.46

D32 80 0.074 10.62 10.2399 0.384 5.190541 -0.6599 -9.4 0.35

D33 81 0.051 11.51 10.945 0.568 11.13725 -1.411005135 -9.1 2.41

D34 82 0.057 11.87 11.2653 0.604 10.59123 -1.019273764 -9.9 0.48

D35 83 0.083 11.03 10.3732 0.655 7.889157 -0.892580998 -9.4 1.59

D36 84 0.067 11.44 10.8253 0.619 9.234328 -0.9272 -9.8 3.78

D37 85 0.058 11.3 10.2909 1.006 17.34655 -1.010066544 -9.8 0.63


35



13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

D38 86 0.071 10.25 9.9807 0.268 3.778873 -1.610044524 -9.5 -0.87

D39 87 0.062 11.66 10.7069 0.949 15.30806 -0.926174216 -9.5 2.93

D40 88 0.079 11.05 10.3261 0.723 9.150633 -0.730054035 -10.2 2.44

D41 89 0.074 11.14 10.4107 0.733 9.909459 -0.62123161 -10.2 2.39

D42 90 0.065 10.63 9.3428 1.288 19.81846 -0.87365229 -9.8 1.34

D43 91 0.066 11.78 11.1298 0.646 9.790909 -0.727325107 -11.2 1.67

D44 92 0.073 11.55 10.8162 0.736 10.07945 -0.564256652 -10.6 2.77

D45 93 0.094 11.81 11.1173 0.688 7.315957 -0.4762 -13 2.86

36

4.2 Yeongwol basin, Yeongwol1 (Namgyo) section


The carbon isotope curve of Yeongwol1 section is in the range of -2.36‰

to +0.95‰, and 0-9.3 m interval show first slight positive curve from -1.6‰

to -0.55‰. After that, the isotope value move toward negative until -1.12‰

record at 19.4 m point, and a large wide second positive curve appears from

20.4m to 32.4 m with maximum carbon isotope value of +0.043‰. The

fluctuation changes +1.16‰ in this interval. Third positive peak is observed

in 46.3 m to 51.4 m interval, with isotopic value changes from -0.58‰ to

+0.95‰. 53.1 m to 64. 6m interval is the missing in Yeongwol1 section, and

after that, the carbon isotope record shows large, highly frequent zigzag

trend. The maximum amount of change is +3.28‰ in the 71.4m-73.4m

interval and it is overlain by dynamic negative peaks, and the smoothed line

show this interval as a pulse with ±0.8‰ fluctuations(Fig 4-4, Table 4-2).

In the cross-plot of carbon and oxygen isotopes, the R2 value of whole

Yeongwol1 section is 0.3659, which is relatively higher than other sections,

but does not indicate whole alteration in isotopic trend (Fig 4-5).

4.2.2 Nitrogen isotope and TIC, TOC, TN contents

The nitrogen isotope value of Yeongwol1 section are high with the mean

value of +8.73‰, and the raw data ranges from minimum +2.86‰ to

maximum +14.3‰. The lowest nitrogen isotope peak appears around 6.3 m,

with the value of +2.86‰, and the largest positive shift occur in 7.3 m to

15.4 m interval, where the amount of increase is maximum +5.55‰ in

smoothed line and +11.44‰ in raw data. After this dynamic interval, data

stays around +6.5‰ with small variation until 37.5 m, and slowly increase

about +4‰ in the 38.5-53.1 m interval. In the upper part after missing

interval, positive shift from +7.21‰ to 14.15‰ is shown in 64.6 m to 70.8 m,

37

and large zigzag pattern appears in raw data after the peak, overlain by the

last negative shift in 91.1m to 99.2m(Fig 4-4, Table 4-2).

The lower part of the Yeongwol1 section show TN around 0.01%, but the

upper part from missing interval show extremely low TN(mostly

38

Fig 4-4. The stable isotope data(δ13Ccarb and δ

15N) and clay mineral composition of the Yeongwol1 section. 3

point moving average smoothed line(red and blue plot), raw data(gray line), the average value(vertical dotted line)

in the isotopic graph. Illite or smectite content(blue area), kaolinite(green area), chlorite(red area) in clay

mineral(%) graph.

39

Fig 4-5. The total nitrogen(TN), total organic carbon(TOC), total inorganic carbon(TIC), CN ratio of the

Yeongwol1 section

40

Fig 4-6. Illite crystallinity values of the Taebaek and the Yeongwol1 sections,

the relationship between illite crystallinity Kubler index(KI), Weaver index(WI)

and Intensity ratio(IR).

41


13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

NG1 0 0.0082 12.082538 11.626 0.45684 55.94866 -1.183061386 -9.843649588 10.25

NG2 1 0.009 12.104001 11.995 0.1088 12.08754 -0.481597893 -7.787436174 4.88

NG3 2 0.0078 12.042715 11.766 0.27712 35.49645 -1.197965002 -8.722442663 5.01

NG4 3 0.008 12.101562 11.583 0.51866 64.9492 -1.421519231 -8.548255159 4.18

NG5 4.1 0.0084 12.012346 11.624 0.38795 46.224 -1.600362615 -9.494273502 3.41

NG6 5.3 0.0067 12.111489 11.628 0.48349 72.62642 -0.872072614 -9.300064445 8

NG7 6.3 0.006 11.976364 11.69 0.28656 47.60852 -0.759798712 -8.789514863 2.86

NG8 7.3 0.0697 12.151127 11.67 0.48163 6.914638 -0.541212354 -8.87060215 6.82

NG9 8.3 0.0063 11.957447 11.716 0.24175 38.50098 -0.548167375 -8.940677583 9.85

NG10 9.3 0.0041 11.867427 11.763 0.10453 25.75188 -0.861143296 -9.222981469 13.65

NG11 10.3 0.0108 11.970732 11.557 0.41363 38.26922 -0.514385847 -9.722519197 4.25

NG12 11.3 0.0062 12.101012 11.846 0.25471 40.98826 -0.541212354 -10.37021641 8.53

NG13 12.3 0.0167 12.218479 11.854 0.36408 21.80808 -0.688261358 -11.17508281 15.19

NG14 13.3 0.0427 12.233114 11.768 0.46521 10.88942 -0.843258958 -10.72660004 7.78

NG15 14.3 0.0078 12.572841 12.566 0.00704 0.899327 -0.571019585 -7.863518072 22.81

NG16 15.4 0.0416 12.344277 11.778 0.56648 13.6174 -0.88498908 -9.699494412 7.24

Table 4-2. Total nitrogen(TN), Total carbon(TC), Total inorganic carbon(TIC), Total organic carbon(TOC),

notation CN ratio and carbon isotope, oxygen isotope, nitrogen isotope with delta of Yeongwol1 section

42


13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

NG17 16.4 0.0374 12.112424 11.617 0.49512 13.22474 -0.873066188 -10.40725628 11.63

NG18 17.4 0.0052 12.092139 11.442 0.65014 125.5377 -0.484578616 -10.11193839 8.32

NG19 18.4 0.0208 11.975028 11.631 0.34453 16.53429 -0.888963378 -9.354122636 14.6

NG20 19.4 0.0071 11.904137 11.413 0.49114 69.54584 -1.124440499 -9.462239018 3.46

NG21 20.2 0.006 11.993238 11.83 0.16364 27.27517 -0.956526434 -9.307071989 6.88

NG22 21.2 0.0059 11.782781 11.16 0.62238 105.0201 -0.714094292 -9.057803663 10.17

NG23 22.2 0.0407 12.025574 11.454 0.57167 14.04714 -0.493520785 -8.741463138 5.54

NG24 23.2 0.0081 12.023648 11.746 0.27765 34.26217 -0.446822791 -8.884617236 5.77

NG25 24.2 0.0126 11.932321 11.617 0.31532 25.00041 -0.297786638 -9.712508421 6.87

NG26 25.2 0.0042 11.842442 11.767 0.07584 18.04126 -0.626659749 -8.808535338 13.9

NG27 26.2 0.0062 11.797261 11.641 0.15616 25.22448 -0.398137647 -8.854584908 6.4

NG28 27.2 0.0034 12.001366 11.876 0.12567 37.4702 -0.433906324 -9.513293977 7.86

NG29 28.4 0.0071 12.00169 11.614 0.38739 54.94578 -0.506437252 -9.408180827 3.67

NG30 29.5 0.0052 12.032626 11.609 0.42343 81.4866 -0.334548889 -8.732453439 11.1

NG31 30.4 0.0071 12.171103 11.973 0.1979 27.67898 0.096662381 -8.208889849 5.47

NG32 31.4 0.0062 12.145386 11.477 0.66799 108.2046 0.067848724 -8.292980368 8.2

NG33 32.4 0.0055 12.328496 11.913 0.4154 75.53761 0.031086473 -8.596306884 5.84


43



13Ccarb

(PDB) (‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

NG34 33.4 0.0069 11.796726 11.424 0.37253 54.16161 0.092688083 -9.324090308 8.52

NG35 34.4 0.0024 11.537945 11.403 0.13494 55.54059 -0.266985833 -8.696414645 6.49

NG36 35.4 0.0046 11.914204 11.512 0.4022 86.77445 -0.070258111 -8.811538571 6.99

NG37 36.3 0.0046 11.927553 11.484 0.44335 96.79647 -0.194454905 -8.892625857 5.83

NG38 37.5 0.0082 11.806383 11.403 0.40378 49.21926 -0.256056515 -8.994735774 5.29

NG39 38.5 0.0442 11.972577 11.46 0.51238 11.59407 -0.315670976 -9.610398505 6.03

NG40 39.5 0.0078 11.558608 10.98 0.57841 74.04041 -0.148750485 -8.852582753 5.18

NG41 40.5 0.0051 11.472214 11.062 0.41011 81.1854 -1.190016407 -11.48641795 9.63

NG42 42.1 0.0051 12.50141 12.105 0.39671 77.36879 -0.055354495 -7.542172159 8.6

NG43 43.3 0.0057 11.374178 10.906 0.46858 82.1136 -0.340510335 -10.15698688 8.83

NG44 44.3 0.0087 11.077349 10.578 0.49955 57.50061 -0.053367347 -8.152829502 6.21

NG45 45.3 0.037 12.166313 11.986 0.18001 4.865899 -0.516372995 -9.178934054 13.76

NG46 46.3 0.0117 11.946198 10.98 0.9665 82.50994 -0.580955328 -9.450226087 6

NG47 47.3 0.0051 12.331901 11.623 0.7091 139.2087 -0.196442054 -5.504979219 11.45

NG48 48.3 0.0045 12.745421 12.092 0.65352 146.6337 -0.014617947 -7.217823013 5.22

NG49 49.3 0.0038 10.700744 10.125 0.57594 152.1296 0.019163581 -9.961776747 10.89

44


13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

NG50 50.4 0.0165 11.941906 11.153 0.78921 47.96331 0.101630252 -7.733377983 5.5

NG51 51.4 0.0107 12.645968 11.921 0.72477 67.87883 0.946168453 -6.579135497 11.76

NG52 52.4 0.009 7.8069644 7.7069 0.10006 11.12911 0.486143527 -5.880383324 11.24

NG53 53.1 0.0271 10.006579 9.2052 0.80138 29.52952 -0.199422777 -7.567199099 7.53

NG54 64.6 0.0115 12.625907 11.332 1.29371 112.5208 -0.676338466 -9.076824138 7.21

NG55 65.6 0.0014 12.255282 11.491 0.76418 535.0363 -0.615730431 -8.486188347 11.09

NG56 66.6 0.0032 11.372409 10.586 0.78601 244.7092 -0.669383446 -8.817545036 8.67

NG57 67.6 0.0377 12.040522 11.648 0.39242 10.42048 -0.463713555 -9.384154965 11.15

NG58 68.6 0.0031 12.546804 12.115 0.432 139.9789 -0.277915151 -9.667459929 12.47

NG59 69.1 0.002 12.617936 11.694 0.92374 466.7264 -0.228236433 -8.016682947 13.07

NG60 70.8 0.0153 12.853954 12.357 0.49695 32.41496 0.317235887 -5.908413497 14.15

NG61 71.4 0.0047 11.596621 11.196 0.40042 84.49808 -2.357466272 -13.40348158 8.14

NG62 72.4 0.0011 12.59661 12.223 0.37371 333.91 0.260602149 -8.985726075 6.32

NG63 73.4 0.0031 13.152356 12.445 0.70786 231.2637 0.922322668 -6.395938294 12.7

NG64 74.4 0.0107 11.980715 10.891 1.08951 102.2866 -0.63162762 -7.650288541 8.11

NG65 75.4 0.002 12.412569 11.803 0.60917 304.6104 -0.719062163 -9.197954529 12.34

NG66 76.4 0.038 11.839602 11.356 0.4839 12.73549 -1.23174653 -9.087835992 9.13


45



13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

NG67 77.4 0.0014 12.388991 11.458 0.93059 646.089 -0.64752481 -9.360129102 12.92

NG68 78.4 0.0041 12.171608 11.209 0.96271 236.1465 0.093681658 -8.384078431 8.65

NG69 79.4 0.0356 11.980851 11.675 0.30575 8.594856 -0.323619571 -8.795521329 8.77

NG70 80.4 0.0336 11.862694 11.549 0.31389 9.336236 -0.244133623 -9.056802586 7.33

NG71 81.4 0.0032 12.355847 11.743 0.61305 192.0988 -0.097084618 -10.41926922 5.16

NG72 83.4 0.0062 12.754596 11.906 0.8487 137.0805 0.537809394 -8.553260547 8.63

NG74 85.4 0.0045 12.855792 12.372 0.48399 106.7136 -0.055354495 -7.867522383 12.24

NG75 86.4 0.0075 11.562209 11.403 0.15891 21.08362 -2.14484136 -14.69086738 7.4

NG76 87.6 0.0445 11.882037 11.475 0.40674 9.142369 0.580533091 -10.77565285 4.77

NG77 89.1 0.0005 12.2793 11.566 0.7135 1562.282 -0.701177825 -9.891701314 11.26

NG78 90.1 2E-05 12.367886 11.246 1.12219 72720.96 -0.56307099 -9.610398505 9.09

NG79 91.1 0.0011 12.128489 11.07 1.05809 959.6284 -0.496501508 -9.76756769 13.43

NG80 92.1 0.0032 11.801784 11.155 0.64668 201.0218 -0.408073391 -10.39824659 11.33

NG81 93.1 0.0022 12.579244 11.901 0.67804 309.1651 -0.303748084 -12.00597723 7.34

NG82 94.1 0.002 13.024211 12.362 0.66261 330.1195 0.364927456 -8.486188347 6.61

NG83 95.2 0.0061 12.900588 12.278 0.62239 101.7411 0.479188507 -8.633346756 6.8

46



13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

δ15N (Air)

(‰)

NG84 96.2 5E-05 13.060283 12.098 0.96238 19968.03 0.752421454 -8.459159251 8.03

NG85 97.2 0.0015 12.755977 11.91 0.84558 560.4846 0.193039093 -11.95492227 6.83

NG86 98.2 0.0013 12.843405 11.992 0.8513 671.9153 0.256220935 -11.67915982 16.99

NG87 99.2 0.0019 12.567994 11.879 0.68879 371.4358 0.471791617 -10.83267414 8.58

47

4.3 Yeongwol basin, Yeongwol2 (Soggol) section


The carbon isotope data of the Yeongwol2 section is in the range of -3.09

‰ to +0.86‰ and mostly stay within -1‰ to +1‰ except for three large

negative values. The δ13C value from the lowermost part of Yeongwol2 is

observed as a negative shift from +0.86‰ to -1.91‰ followed by positive

shift cut by missing interval. The disconnected positive curve is overlain by

the most negative peak over -3‰ at the 62.86 m point. After this negative

peak, the large wide positive excursion reaching +0.77‰ at 75.26 m point

occurs, and continues to until the 79m point. The combination of -1.05‰

negative excursion at 80m and following +0.58‰ positive excursion at 84.26

m record the final peak (Fig 4-7, Table 4-3).

YW2 section has R²= 0.2865 in δ 18

O and δ 13

C cross-plot, which

indicates a little relationship between two factors, and the lesser possibility

of whole alteration in isotopic trend (Fig 4-3).

4.3.2 TIC, TOC, TN contents

Yeongwol2 section was not analyzed for the nitrogen isotope, due to

extremely low TN (mostly

48

Fig 4-7. The stable isotope data(δ13Ccarb) and total nitrogen(TN), total organic carbon(TOC), total inorganic

carbon(TIC), CN ratio of the Yeongwol2 section. 3 point moving average smoothed line(red line), raw data(gray

line), the average value(vertical dotted line) in the isotopic graph.

49


13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

S43 43.2 0.002204 13.25793 12.5686 104.7383 312.7756 0.857740335 -6.548102091

S44 44.7 0.003532 12.61652 11.8019 98.34913 230.6234 -0.274934427 -7.961623678

S45 45.9 0.004058 13.09806 12.3232 102.6933 190.9489 0.057912981 -7.224830556

S46 46.9 0.002965 13.09954 12.188 101.5666 307.475 -0.698197102 -12.03701064

S47 47.9 0.002313 12.57105 11.8703 98.91913 302.9263 -0.83928466 -14.40055488

S48 49.1 0.001918 11.84351 10.6843 89.0358 604.3873 -1.235720827 -13.92904732

S49 50.1 0.000725 13.33622 12.3682 103.0683 1334.527 0.104610975 -7.036627965

S50 51.1 0.001163 12.51445 11.7407 97.83913 665.4136 -1.912344962 -10.05087265

S51 52.1 0.004841 11.6166 10.8041 90.03413 167.8515 -0.437880621 -8.553260547

S52 53.1 0.001865 13.0964 12.3285 102.7375 411.8201 -0.970436475 -8.375068732

S53 53.9 0.002757 13.06892 12.3167 102.6391 272.8303 0.257621426 -7.194798228

S54 58.86284 0.001956 13.05388 12.3261 102.7175 372.1511 -0.573006733 -7.099695855

S55 59.86284 0.000844 13.28888 12.449 103.7416 995.2683 -0.630634046 -7.261870428

S56 60.86284 7.19E-05 13.12307 12.3735 103.1125 10426.31 -0.481597893 -7.033624732

S57 61.86284 0.002748 13.26035 12.5541 104.6175 256.9597 -0.711113569 -7.99465924

S58 62.86284 0.000294 12.12284 11.4419 95.34913 2312.526 -3.093704868 -11.13303755

S59 63.86284 0.000179 12.98152 12.2782 102.3183 3921.386 -1.250624442 -10.85273582

Table 4-3. Total nitrogen(TN), Total carbon(TC), Total inorganic carbon(TIC), Total organic carbon(TOC), CN

ratio and carbon isotope, oxygen isotope, nitrogen isotope with delta of Yeongwol2 section

50



13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

S60 64.86284 0.000176 12.13074 11.499 95.82496 3594.049 -0.913802737 -12.81084363

S61 65.86284 0.001359 13.15282 11.8773 98.97746 938.8465 -0.795567389 -13.03708717

S62 67.06284 0.001848 12.49077 11.7316 97.76329 410.6979 -0.815438876 -18.19163579

S63 68.06284 0.00204 13.33345 12.4749 103.9575 420.9007 0.072816596 -8.205886616

S64 69.06284 0.004569 13.16654 12.1734 101.445 217.3679 0.389766815 -7.981645231

S65 70.06284 0.001225 13.27547 11.966 99.71663 1068.84 0.55072586 -7.75139738

S66 71.06284 0.003862 13.35489 12.1662 101.385 307.7986 0.31326159 -7.944605359

S67 72.06284 0.003911 13.36953 12.1559 101.2991 310.3036 0.415599748 -7.674314404

S68 73.26284 0.005436 13.12145 12.0899 100.7491 189.7767 0.423548343 -7.673313326

S69 74.26284 0.002085 13.39544 11.4856 95.7133 915.9286 0.584507388 -7.787436174

S70 75.26284 0.007929 13.34549 12.0552 100.46 162.7245 0.767325069 -7.544174314

S71 76.26284 0.000637 13.35329 12.1898 101.5816 1826.11 0.370888902 -7.789438329

S72 77.26284 0.003856 13.27762 12.3907 103.2558 230.0109 0.00525354 -7.765412467

S73 78.26284 8.67E-05 13.15389 12.4369 103.6408 8273.991 0.528867224 -8.480181881

S74 79.26284 0.00267 13.39523 12.3902 103.2516 376.4368 -0.397144073 -8.328018084

S75 80.26284 0.001491 13.29824 12.401 103.3416 601.825 -1.050915997 -7.845498675

S76 81.26284 0.002129 12.82016 12.6034 105.0283 101.8287 0.159257565 -9.249009487

S77 82.26284 0.003546 13.31297 11.9455 99.54579 385.6005 0.239737088 -8.126801484

51



13Ccarb (PDB)

(‰)

δ18Ocarb (PDB)

(‰)

S78 83.26284 0.001858 13.23832 11.957 99.64163 689.468 0.311274441 -7.773421087

S79 84.26284 0.000166 13.33351 11.7281 97.73413 9692.453 0.584507388 -8.160838123

S80 85.26284 0.001008 13.27347 11.5097 95.91413 1750.234 0.500053568 -7.947608592

S81 86.26284 0.001105 12.7752 12.0769 100.6408 631.9493 -0.173589843 -8.125800407

S82 87.26284 0.002876 13.33788 12.5484 104.57 274.5514 0.217878452 -7.103700165

52

Table 4-4. The XRD analysis results of air-dired(001Air, 003Air), glycolated(001gly ,003gly) sample peaks, internsity of

10.0Å, 10.5 Å point, KI(Kuber index), WI(Weaver index), IR(Internsity ratio), and illite(Ill(%)), chlorite(Chl(%)),

Kaolinite(Kao(%)) content to total clay ratio, from Taebaek section

Name Height(m) KI 001Air 003Air 001gly 003gly 10.0Å(i) 10.5Å(i) WI IR Ill(%) Chl(%) Kao(%)

M1 0 0.1093 187.11 71.25 419.38 325.59 37 20 1.85 2.04 81.58 10.53 7.895

M2 1 0.2362 65.82 52.48 79.72 58.66 49 46 1.07 0.92 68.97 6.897 24.14

M3 2 0.1181 257.29 25.16 117.06 111.14 54 17 3.18 9.71 94.34 4.852 0.809

M4 3 0 0 0 25.66 0 12 11 1.09 0 35 35 30

M5 4 0.1968 107.27 55.15 146.34 106.8 49 22 2.23 1.42 94.02 4.843 1.14

M6 5 0.1181 168.76 24.91 571.89 314.89 37 16 2.31 3.73 63.33 23.33 13.33

M7 6 0.0984 165.57 31.62 466.65 209.97 72 11 6.55 2.36 82.14 10 7.857

M8 7 0.1181 792.58 435.12 699.77 0 168 56 3 0 75.68 16.22 8.108

M9 8 0.1181 36.42 0 0 0 14 19 0.74 0 47.62 28.57 23.81

M10 9 0.1181 27.5 43.7 0 0 19 14 1.36 0 62.5 15.63 21.88

25-45 10 0.0984 332.14 164.46 247.31 157.54 52 47 1.11 1.29 90.11 3.297 6.593

J1 12 0.1378 190.2 71.43 185.15 98.62 69 65 1.06 1.42 66.67 7.843 25.49

J2 14 0 0 0 139.92 99.97 22 17 1.29 0 70 12.5 17.5

J3 15 0.1181 52.76 44.39 133.32 98.96 12 17 0.71 0.88 47.95 12.33 39.73

J4 16 0.1574 63.26 20.86 33.27 0 59 58 1.02 0 29.17 38.89 31.94

J5 17 0.1181 141.55 57.39 49.97 0 87 55 1.58 0 40.85 8.497 50.65

53



J6 18 0.1574 146 76.99 0 90.8 88 50 1.76 0 53.06 36.73 10.2

J7 19 0.1574 0 0 50.31 0 37 25 1.48 0 40.73 10.39 48.88

J8 20 0.1181 79.34 22.84 26.27 0 78 64 1.22 0 37.88 44.32 17.8

J9 21 0.1574 47.33 47.68 24.46 50.3 52 66 0.79 2.04 32.26 48.39 19.35

J10 22 0 0 0 0 0 22 19 1.16 0 7.143 7.143 85.71

J22 23 0 0 30.97 0 49.27 52 54 0.96 0 1.754 15.79 82.46

J23 24 0 0 83.39 0 74.94 60 63 0.95 0 6.173 11.52 82.3

J24 25 0 0 53.22 0 31.9 56 69 0.81 0 5.736 13.96 80.31

J25 26 0 0 21.46 0 0 9 12 0.75 0 7.984 14.17 77.84

J26 27 0.1181 29.02 165.86 0 68.76 15 17 0.88 0 5.172 15.52 79.31

J27 28 0 0 48.15 0 73.8 50 65 0.77 0 4.167 50 45.83

J28 29 0 0 27.37 0 0 50 71 0.7 0 22.26 10.97 66.77

J29 30 0 0 45.51 0 0 59 58 1.02 0 8.333 16.67 75

J30 31 0 0 49.56 0 56.68 51 58 0.88 0 8.357 64.07 27.58

J31 32 0 0 35.98 0 0 69 52 1.33 0 1.695 25.42 72.88

J32 33 0 0 28.9 52.18 48.14 36 56 0.64 0 24.02 6.114 69.87

J33 34 0 0 40.87 0 50.61 67 69 0.97 0 1.65 7.591 90.76

54



J34 35 0.4723 11.45 43.07 0 82.72 31 20 1.55 0 1.923 7.692 90.38

J35 36 0 0 22.49 0 38.96 63 48 1.31 0 5.208 13.19 81.6

J36 37 0 0 0 24.53 70.19 60 57 1.05 0 7.018 15.79 77.19

J37 38 0 0 0 0 0 46 60 0.77 0 3.226 43.55 53.23

J38 39 0 0 0 0 0 62 60 1.03 0 2.326 65.12 32.56

J39 40 0 0 19.02 0 15.75 36 50 0.72 0 5.698 14.53 79.77

J40 41 0 0 29.95 0 0 61 45 1.36 0 2.5 62.5 35

J41 42 0 0 16.75 0 0 45 46 0.98 0 4.167 66.67 29.17

J42 43 0 0 0 0 0 28 21 1.33 0 3.226 58.06 38.71

J43 44 0 0 13 0 0 17 21 0.81 0 3.846 19.23 76.92

J44 45 0.2362 29.33 37.28 0 0 81 49 1.65 0 2.778 44.44 52.78

J45 46 0.6298 17.15 33.76 20.98 0 58 48 1.21 0 5.263 52.63 42.11

J46 47 0 0 45.02 50.94 36.43 49 47 1.04 0 2.5 62.5 35

J47 48 0.2362 31.78 28.86 0 0 64 55 1.16 0 4 18 78

D1 49 0 0 0 94.62 80.24 22 34 0.65 0 56.52 10.87 32.61

D2 50 0 0 0 0 0 52 54 0.96 0 32.79 34.43 32.79

D3 51 0 0 0 0 0 48 48 1 0 24.39 26.83 48.78

D4 52 0.2362 24.84 22.83 0 0 71 64 1.11 0 35.71 28.57 35.71

55



D5 53 0.1181 339.08 156.15 574.3 320.23 101 61 1.66 1.21 0 100 0

D6 54 0.1181 339.08 156.15 377.48 0 82 55 1.49 0 55.97 43.61 0.417

D7 55 0.1574 355.52 140.77 224.17 0 144 66 2.18 0 75.27 3.226 21.51

D8 56 0.1574 62.57 32.59 36.06 0 58 56 1.04 0 22.86 31.43 45.71

D9 57 0.1181 80.14 31.2 161.39 104.93 24 18 1.33 1.67 68.18 22.73 9.091

D10 58 0.1181 337.27 205.39 656.68 351.69 76 50 1.52 0.88 33.33 25.93 40.74

D11 59 0.1181 53.88 19.7 66.57 63.41 55 60 0.92 2.61 12.24 51.02 36.73

D12 60 0.1574 111.67 71.12 30.69 67.69 73 53 1.38 3.46 42.86 28.57 28.57

D13 61 0 0 0 106.43 91.87 23 14 1.64 0 89.01 5.236 5.759

D14 62 0.1181 53.51 38.27 81.43 80.4 31 17 1.82 1.38 39.22 41.18 19.61

D15 63 0.1181 367.46 159.44 544.22 364.24 106 60 1.77 1.54 18.75 15.63 65.63

D16 64 0 0 0

72.5 50 65 0.77 0 30 25 45

D17 65 0.1181 52.46 24.07 110.02 209.78 50 65 0.77 1.44 28.57 21.43 50

D18 66 0.0984 610.4 215.23 353.03 232.59 174 49 3.55 1.69 76.19 4.762 19.05

D19 67 0.2362 12.02 0 408.86 106.04 10 21 0.48 0 57.69 23.08 19.23

D20 68 0.1574 214.7 110.26 143.99 247.6 109 51 2.14 1.43 82.8 10.19 7.006

D21 69 0.1181 273 1196 269.53 69.11 66 49 1.35 0.21 50.76 13.71 35.53

D22 70 0 0 0 113.06 52.17 9 15 0.6 0 83.64 9.091 7.273

56



D23 71 0.1181 55.72 19.98 97.19 43.28 23 12 1.92 1.5 29.17 20.83 50

D24 72 0.1968 51.73 24.27 60.66 24.67 72 56 1.29 1.52 10.53 47.37 42.11

D25 73 0.2362 20.5 24.24 46.89 90.34 41 45 0.91 0.44 39.6 30.69 29.7

D26 74 0.0984 320.16 103.22 271.17 35.4 106 60 1.77 1.03 80.77 11.54 7.692

D27 75 0.1181 138.92 74.66 53.25 532.42 60 56 1.07 1.24 25.64 20.51 53.85

D28 76 0.0984 610.4 215.23 932.02 45.33 132 61 2.16 1.62 52.43 6.796 40.78

D29 77 0 0 35.2 36.95 0 56 56 1 0 41.67 25 33.33

D30 78 0.1968 23.32 0 41.29 211.63 36 45 0.8 0 48.57 18.57 32.86

D31 79 0.1181 92.68 39.14 244.02 83.83 23 22 1.05 2.05 5.731 5.444 88.83

D32 80 0.0984 95.55 50.43 164.31 397.06 42 50 0.84 0.97 18.52 48.15 33.33

D33 81 0.1181 108.85 64.89 687.17 278.69 32 9 3.56 0.97 56 43.57 0.429

D34 82 0.1181 162.67 128.87 299.43 0 87 74 1.18 1.17 98.37 0.761 0.864

D35 83 0.1574 53.77 21.3 115.79 85.72 58 60 0.97 1.87 29.17 20.83 50

D36 84 0.0984 292.31 107.98 238.79 158.14 123 56 2.2 1.79 50.63 24.05 25.32

D37 85 0.1968 32.16 11.47 0 0 43 50 0.86 0 36.36 27.27 36.36

D38 86 0.1181 64.39 52.91 21.29 80.84 18 19 0.95 4.62 69.77 16.28 13.95

D39 87 0.1181 147.66 60.3 414.85 221.41 28 11 2.55 1.31 79.14 10.07 10.79

57



D40 88 0.1378 209.08 109.99 91.27 48.69 77 62 1.24 1.01 64.17 9.091 26.74

D41 89 0.0984 376.46 152.18 277.3 117.2 12 20 0.6 1.05 50 25 25

D42 90 0.0984 369.27 124.93 660.65 306.07 12 19 0.63 1.37 64.94 15.58 19.48

D43 91 0.1181 295.58 112.08 127.13 86.45 93 60 1.55 1.79 63.64 9.091 27.27

D44 92 0.1181 32.27 10.97 201.75 141.04 16 18 0.89 2.06 68.18 16.67 15.15

D45 93 0.0984 148 90.61 153.3 43.61 79 56 1.41 0.46 30.43 45.65 23.91

58

Table 4-5. The XRD analysis results of air-dired(001Air, 003Air), glycolated(001gly ,003gly) sample peaks, internsity of

10.0Å, 10.5 Å point, KI(Kuber index), WI(Weaver index), IR(Internsity ratio), and illite(Ill(%)), chlorite(Chl(%)),

Kaolinite(Kao(%)) content to total clay ratio, from Yeongwol1 section.


NG1 0 0.0984 54.13 653.51 80.65 501.3 34 19 1.789 0.515 38.095 14.286 47.619

NG2 1 0 0 36.96 449.63 406.1 50 45 1.111 0 64.179 16.418 19.403

NG3 2 0 0 0 0 0 57 55 1.036 0 31.111 24.444 44.444

NG4 3 0.2362 24.83 0 18.9 221.8 53 48 1.104 0 30.189 43.396 26.415

NG5 4.1 0.1181 79.19 50.64 28.17 0 26 14 1.857 0 42.553 44.681 12.766

NG6 5.3 0.1574 31.02 16.32 0 65.64 50 59 0.847 0 17.391 50 32.609

NG7 6.3 0.1378 83.67 47.38 17.13 31.04 64 57 1.123 3.2 38.182 29.091 32.727

NG8 7.3 0.1181 66.87 51.17 172.15 486.5 35 17 2.059 3.693 40 30 30

NG9 8.3 0.1181 86 37.52 119.12 564.4 31 23 1.348 10.86 65.217 13.043 21.739

NG10 9.3 0 0 11.72 108.74 274.9 21 23 0.913 0 1.4164 2.2663 96.317

NG11 10.3 0 0 20.89 294.13 303.2 11 17 0.647 0 15.094 28.302 56.604

NG12 11.3 0.1181 53.85 56.13 120.18 293.9 17 17 1 2.346 6.25 5.2083 88.542

NG13 12.3 0 0 18.63 63.4 43.62 57 64 0.891 0 70 25.714 4.2857

NG14 13.3 0.1181 53.24 320.56 8.9 19.52 63 56 1.125 0.364 55.777 20.319 23.904

NG15 14.3 0.1181 92.91 206.91 65.86 134.9 31 20 1.55 0.92 49.057 22.642 28.302

NG16 15.4 0.0984 46.33 83.66 80.21 313.6 21 19 1.105 2.165 51.282 37.179 11.538

59



NG17 16.4 0 0 25.06 0 0 54 53 1.019 0 35.294 35.294 29.412

NG18 17.4 0 0 0 25.77 0 51 53 0.962 0 42.553 12.766 44.681

NG19 18.4 0.0984 100.9 61.04 251.54 664.3 21 19 1.105 4.365 97.039 2.1382 0.8224

NG20 19.4 0.1574 86.15 214.59 158.52 425 31 21 1.476 1.076 38.095 33.333 28.571

NG21 20.2 0.0984 72.74 205.47 313.83 971.1 21 14 1.5 1.095 28.571 42.857 28.571

NG22 21.2 0.0984 113.59 325.41 246.96 974 28 23 1.217 1.377 27.778 22.222 50

NG23 22.2 0.1181 102.9 95.42 149.61 205.1 30 19 1.579 1.479 39.535 53.488 6.9767

NG24 23.2 0.1181 60.56 34.25 283.3 388.7 31 20 1.55 2.426 38.018 29.525 32.457

NG25 24.2 0.1181 129.78 337.44 134.24 362.6 76 20 3.8 1.039 97.81 0.7299 1.4599

NG26 25.2 0.1181 93.3 51.69 249.5 1570 38 18 2.111 11.36 35.714 28.571 35.714

NG27 26.2 0.1181 87.21 59.08 63.9 332 38 20 1.9 7.669 40 20 40

NG28 27.2 0.1181 286.09 231.11 226.48 304.4 30 16 1.875 1.664 37.5 37.5 25

NG29 28.4 0 0 35.13 0 37.36 42 57 0.737 0 16 32 52

NG30 29.5 0.2362 26.98 559.48 0 71.48 57 39 1.462 0 12 12 76

NG31 30.4 0.9446 5.81 126.88 0 109.4 24 19 1.263 0 48.276 41.379 10.345

NG32 31.4 0.0984 98.47 45.98 125.84 74.57 64 66 0.97 1.269 47.368 36.842 15.789

NG33 32.4 0.1574 61.49 78.53 131.75 283.3 17 28 0.607 1.683 62.857 10 27.143

NG34 33.4 0.1181 76.93 49.99 385.49 180.3 20 25 0.8 0.72 83.333 9.7222 6.9444

60



NG35 34.4 0.1181 56.63 41.26 70.58 0 17 14 1.214 0 56.604 9.434 33.962

NG36 35.4 0.1181 94.34 38.88 194.32 82.53 25 25 1 1.031 0 100 0

NG37 36.3 0.0984 189.43 106.79 72.33 0 78 63 1.238 0 36.697 26.606 36.697

NG38 37.5 0.9446 7.54 52.35 49.88 179.2 19 12 1.583 0.518 55.942 43.58 0.4776

NG39 38.5 0.1181 168 36.61 62.96 79.11 32 17 1.882 5.766 25 58.333 16.667

NG40 39.5 0.2362 26.98 559.48 250.65 121.5 61 53 1.151 0.023 40 40 20

NG41 40.5 0.2362 17.94 76.83 40.53 135.2 48 55 0.873 0.779 25 50 25

NG42 42.1 0 0 21.17 43.02 0 21 15 1.4 0 45.714 25.714 28.571

NG43 43.3 0.0984 48.03 131.78 112.12 245.5 28 21 1.333 0.798 33.333 26.667 40

NG44 44.3 0.1181 70.15 39.14 260.7 107.1 35 16 2.188 0.736 52.632 21.053 26.316

NG45 45.3 0.1181 51.76 72.33 195.6 322.4 22 18 1.222 1.179 21.429 35.714 42.857

NG46 46.3 0.1574 191.39 0 0 47.54 103 63 1.635 0 74.242 10.606 15.152

NG47 47.3 0.1378 129.02 78.17 55.93 46.4 81 49 1.653 1.369 33.333 50 16.667

NG48 48.3 0.1574 190.12 0 71.58 60.61 86 54 1.593 0 38.462 30.769 30.769

NG49 49.3 0 0 0 0 0 13 11 1.182 0 31.25 18.75 50

NG50 50.4 0.2362 11.63 54.51 0 74.16 18 10 1.8 0 55.556 24.074 20.37

NG51 51.4 0.1181 37.35 78.43 93.66 303.2 16 11 1.455 1.542 31.746 36.508 31.746

NG52 52.4 0.1574 37.3 29.45 69.94 87.7 24 19 1.263 1.588 42.857 21.429 35.714

61



NG53 53.1 0.2362 14.49 13.98 38.2 74.39 20 16 1.25 2.018 84.691 6.5147 8.7948

NG54 64.6 0.1181 136.66 76.66 454 295.3 31 18 1.722 1.16 37.963 29.63 32.407

NG55 65.6 0.1574 58.31 31.59 95.79 83.91 26 22 1.182 1.617 53.226 41.935 4.8387

NG56 66.6 0.1181 48.17 22.2 46.99 0 19 17 1.118 0 78.014 7.8014 14.184

NG57 67.6 0.0984 399.79 229.59 85.73 0 81 62 1.306 0 81.818 9.0909 9.0909

NG58 68.6 0.1181 568.56 317.17 790.05 742.5 43 22 1.955 1.685 55.263 21.053 23.684

NG59 69.1 0 0 0 0 0 12 20 0.6 0 38 30 32

NG60 70.8 0.1574 23.11 84.79 55.16 63.79 18 12 1.5 0 38.889 25 36.111

NG61 71.4 0.1574 90.19 0 80.78 67.52 83 37 2.243 0.889 37.879 29.293 32.828

NG62 72.4 0 0 48.82 0 0 39 58 0.672 0 25.714 51.429 22.857

NG63 73.4 0.1181 100.11 58.24 266.42 186.1 38 23 1.652 1.433 63.218 22.414 14.368

NG64 74.4 0.1181 144.79 124.01 290.2 144.6 26 18 1.444 1.238 75.269 11.828 12.903

NG65 75.4 0.1181 209.77 31.32 259.06 223.1 37 16 2.313 1.457 92.077 5.7816 2.1413

NG66 76.4 0.1181 56.77 43.04 69.11 78.16 29 24 1.208 2.05 45.833 12.5 41.667

NG67 77.4 0.1181 64.71 30.25 59.53 115.4 19 19 1 2.914 15.789 42.105 42.105

NG68 78.4 0.1181 72.34 134.72 70.18 0 14 22 0.636 0 59.259 18.519 22.222

NG69 79.4 0.1181 22.01 35.22 64.07 0 25 20 1.25 0 50 22.222 27.778

NG70 80.4 0.1181 89.03 192.3 155.22 140 26 16 1.625 2.28 37.975 29.114 32.911

62



NG71 81.4 0.0984 327.46 68.69 71.35 0 123 71 1.732 0 37.975 29.114 32.911

NG72 83.4 0.1378 108.41 0 26.3 20.97 38 26 1.462 1.258 25 50 25

NG73 84.9 0 0 36.92 0 0 51 61 0.836 0 33.333 28.205 38.462

NG74 85.4 0.1378 100.76 42.55 493.81 521 59 27 2.185 2.879 65.625 21.875 12.5

NG75 86.4 0 0 0 361.36 231.6 70 48 1.458 0 32.787 34.426 32.787

NG76 87.6 0 0 613.73 0 0 13 9 1.444 0 38.182 29.091 32.727

NG77 89.1 0.1574 861.42 0 309.84 118.9 145 64 2.266 0.539 75.342 14.384 10.274

NG78 90.1 0 0 128.3 0 0 54 59 0.915 0 95.745 2.1277 2.1277

NG79 91.1 0.0984 214.44 87.64 82.46 76.97 76 53 1.434 1.56 37.975 29.114 32.911

NG80 92.1 0.1181 156 116.07 0.2519 0 95 50 1.9 0 29.412 26.471 44.118

NG81 93.1 0.1181 228.79 34.32 285.18 250.9 41 12 3.417 1.734 45.833 35.417 18.75

NG82 94.1 0.1181 64.16 0 144.01 117 22 18 1.222 1.519 47.17 26.415 26.415

NG83 95.2 0 0 218.07 0 0 15 13 1.154 0 35 35 30

NG84 96.2 0.1378 263.04 36.71 175.35 148.6 125 42 2.976 1.022 28.571 47.619 23.81

NG85 97.2 0.3149 26.09 134.92 0 0 56 61 0.918 0 29.63 22.222 48.148

NG86 98.2 0.1181 54.54 39.54 182.2 428.3 17 22 0.773 0.95 76.19 9.5238 14.286

NG87 99.2 0.1181 63.99 0 0 0 66 57 1.158 0 34.211 36.842 28.947

63

CHAPTER 5. DISCUSSION

5.1 Regional Chemostratigraphy

The Taebaek and the Yeongwol2 sections have sharp-shaped negative

peaks and large positive peaks which can be specified as the MDICE. The

positive excursion seems to be more pronounced than a Yeongwol1 section

because they exactly contain the Middle Ordovician period. The Yeongwol1

section contains much wider time period than Taebaek and Yeongwol2. Also,

this section was in the platform far from the continent unlike the Taebaek

section, and therefore could have developed relatively moderate shape of

MDICE (Patterson and Walter, 1994; Holmden et al., 1998; Immenhauser et

al., 2002). However, considering the carbon isotope fluctuation range and

sequence stratigraphic information in this environment, broad peaks at the

lower part of Yeongwol1 section can be compared to the three peaks of

carbon isotope curves from the Taebaek and Yeongwol2 (Fig 5-1). The

sharp negative spike of each section overlain by MDICE can be correlated

to the lower Darriwilian negative carbon isotope excursion (LDNICE; Lehnert

et al., 2014).

The upper part of Yeongwol1 section reflects carbon isotope changes in

the late Darriwilian to early Sandbian period based on the temporal

background of biography and sequence stratigraphy, and it also shares some

features with the Baltica carbon isotope record, especially with BC6 and

BC10 shapes(Fig 5-4). The carbon and nitrogen isotope variations in the

upper Yeongwol1 section show sharp zigzag patterns, suggesting that this

area was in the environment with large variation in isotope value. It

requires consideration on the similar global records and mechanism of the

seawater stratification. This interpretation will be further discussed in the

paleoceanographic model.

64

Fig 5-1. Correlations between regional carbon isotope chemostratigraphy of Taebaek, Yeongwol1, Yeongwol2

section

65

5.2 Environmental condition

5.2.1 Sea water stratification

The Taebaek section shows low total organic carbon (TIC) content,

especially in the Jigunsan Formation with black shale. Considering the

sedimentation process of the black shale, a large amount of organic matter

including organic carbon and nitrate component should have been

accumulated and preserved at the time of deposition, leading to the black

color of shale. However, this organic matter may have experienced early

diagenesis and biodegradation, and reduced TOC, TN value in the black

shale part may implicate this secondary decomposition (Freudenthal et al.,

2001; Tyson, 1995).

Although previous studies report that there was a burial event accompanied

by heat on the Jigunsan and the Duwibong formations, the metamorphism

states of both formations are only in the heated diagenesis stage, epizone

(Lee and Ko, 1997). Carbon isotope has been little affected by meteoric

water (Fig 4-3), and in spite of weakened relationships, bulk rock nitrogen

isotope still reflects the primary signal of the time of deposition (Ader et al.,

1998; Pitcairn et al., 2005). The primary signal from δ15N curve indicates

that the positive shift implies the sea water stratification which promotes

the intensified denitrification of nitrate in the reduction state (Herbert, 1999;

Joye and Paerl, 1994; Wang et al., 2015).

The positive nitrogen isotope excursion of the Taebaek section is

accompanied by the sharpest and the broadest carbon isotope peaks of the

MDICE (Fig 4-1). This correspondence of two isotopic excursions indicates

that the time of the largest peak of MDICE may coincide with the high

decomposition of organic matter in deep oceanic stratification, with increased

deposition of carbonate (Fig 4-2).

In the Yeongwol1 section, the carbon and nitrogen isotope values have

higher averages and smaller fluctuations which are characteristics of

66

environment farther from the shore even in the similar epeiric sea

conditions (Schoeninger and DeNiro, 1984). The nitrogen isotope curve of

lower Yeongwol1 section appears low and flat when the carbon isotope

curve draws a broad peak of +1.2‰(20.2m-39.5m). Rather, the positive

nitrogen isotope excursion of this section is close to the timing of the first

MDICE peak with maximum +19.95‰ shift(6.3-14.3 m), and then +8.26‰

shift(40.5-45.3 m) around to the third peak. As in the Taebaek section, these

data indicate the influence of the intensified seawater stratification of the

Yeongwol area in the early MDICE interval. However, the Yeongwol1 record

is different from the Taebaek record, in that the third MDICE peak interval

show less stratified sea water condition (28.4-39.5 m) and then become more

stratified again at the end of the MDICE interval. The upper part of

Yeongwol1 section shows a very sharp zigzag pattern of δ15N as well as an

irregular pattern drawn by δ13C. The reliability of the nitrogen isotope as

the primary signal at this section is considerably low (Fig 4-4), but the trend

of the nitrogen isotope curve is moving from a significantl

Documents

Disclaimer - s-space.snu.ac.krs-space.snu.ac.kr/bitstream/10371/131441/1/000000142192.pdfcurves from carbonate platform and carbonate mound sediments show largely similarity to those