Sedimentary processes and depositional environments of the gas-bearing Horn River Shale in British Columbia, Canada

Seok Hoon Yoon,Young Jin Joe,Chang Seong Koh,Ju Hwan Woo,Hyun Suk Lee 한국지질과학협의회 2018 Geosciences Journal Vol.22 No.1

The Horn River Basin in the northeastern British Columbia, Canada, is one of the largest unconventional gas-bearing basins in North America. The main reservoir of this gas accumulation is the Devonian Horn River Formation that is stratigraphically divided into three members, the Evie, Otterpark and Muskwa in ascending order. This study focuses on sedimentary processes and depositional environments of the Horn River Formation based on sedimentary facies analysis by the aid of well-log mineralogy (ECS) and total organic carbon (TOC) data from the Kiwigana well. The shales of the formation consist dominantly of silicate minerals (quartz, feldspar and mica) and subordinate clay mineral and carbonate materials, with TOC ranging from 0.3 to 7.6%. Three sedimentary facies were identified on the basis of centimeter-scale description of sedimentary structures and texture in borehole cores: homogeneous mudstone (HM), indistinctly laminated mudstone (ILM), and planar laminated mudstone (PLM). Integration of sedimentary facies, lithology and TOC suggests that the Horn River shale was primarily deposited in overall distal marine setting deeper than shelf or marginal slope, possibly base-of-slope to deeper basin plain off the carbonate reef (or shelf). Facies HM is siliceous and organic-rich, and dominant in the Evie and the overlying lowermost Otterpark members. It is interpreted as a pelagic to hemipelagic deposit formed mainly by suspension fall-out in an anoxic setting below maximum storm wave base. Likewise, facies ILM shows relatively high proportion of silicate minerals and TOC. This facies is identified frequently in the Muskwa and rarely in the Otterpark; it reflects a deposition from hemipelagic settling with an influence of persistent and weak bottom currents or nepheloid flows. Facies PLM, dominant in the large part of the Otterpark, is relatively depleted in silicate minerals and TOC. This facies indicates more frequent inflow of episodic turbidity currents punctuating the hemipelagic settling of the background sedimentation process. During the deposition of the Horn River Formation, the depositional site has experienced an earlier relative sea-level fall changing from a deep basin (Evie) to shallower marginal slope (middle Otterpark), and subsequent relative sea-level rise turning back to a deeper marine environment (Muskwa).

강릉시 불화산 일대 뢰스 퇴적층의 형성 과정과 퇴적 환경

박충선 ( Chung Sun Park ),윤순옥 ( Soon Ock Yoon ),황상일 ( Sang Il Hwang ) 한국지형학회 2014 한국지형학회지 Vol.21 No.3

본 연구는 강릉시 불화산 일대에 분포하고 있는 뢰스 퇴적층을 포함한 제4기 미고결 퇴적층의 형성 과정과 퇴적 환경을 밝히고자 한다. 최상부의 Unit I은 점토질 실트 퇴적층으로, 일반적으로 국내에서 확인된 뢰스 퇴적층에 해당하는 퇴적상 및 입도 특성을 보인다. 따라서 Unit I은 장거리 운반에 의해 퇴적된 뢰스 퇴적층으로 생각되지만, 국내 다른 지역에서 보고된 뢰스 퇴적층보다 주변에서 기원한 물질을 더 포함하고 있다. Unit II는 전체적으로 상부의 Unit I과 유사한 뢰스 퇴적층이지만, Unit I보다 주변에서 기원한 물질을 더 많이 포함하고 있어, 점이적인 층준으로 생각된다. 최하부의 Unit III는 모래가 주를 이루고 있으며 층리 구조가 확인되어, 해안단구 퇴적층으로 생각된다. 그러나 Unit III-1과 Unit III-2는 입도 조성이 상이하여, 동일하게 파랑의 작용에 의해 형성되었다 하더라도 서로 다른 퇴적 환경에서 형성된 해안단구 퇴적층인 것으로 생각된다. This study aims to reveal formative process and sedimentary environment of Quaternary unconsolidated sediments including loess sediments distributing around Mt. Bulhwa, Gangneung-si, South Korea. Uppermost Unit I is clayey silt sediments and shows sedimentary facies and grain size properties corresponding to loess sediments in Korea, suggesting that Unit I is loess sediments through long-distance transport with more locally derived materials than loess sediments in Korea. Unit II is also considered as loess sediments similar to Unit I with more locally derived materials than Unit I, indicating a transitional horizon. Bottommost Unit III consists mainly of sand grains with a bedding structure, suggesting marine terrace deposits. Because Unit III-1 and Unit III-2 indicate different properties in grain size, however, they seem to be marine terrace deposits under different sedimentary environments in spite of the same formative process.

캐나다 앨버타주 몬트니층의 퇴적상과 퇴적환경: 가스함유 셰일층의 파쇄효율 향상을 위한 퇴적학적 특성화

윤석훈,조영진 대한지질학회 2019 지질학회지 Vol.55 No.3

캐나다 앨버타주에 분포하는 몬트니층은 중생대 트라이아스기 초기에 형성된 가스함유 셰일층으로서, 이 연구에서는 셰일가스층 개발 시 파쇄특성을 결정하는 근원암저류층의 퇴적학적 다양성을 이해하기 위하여Kakwa 시추공 코어(총연장 약 200 m)에서 퇴적상 분석을 통해 퇴적작용과 형성환경을 해석하였다. 연구지역의 몬트니층은 전 구간에 걸쳐 60% 내외의 석영과 장석을 함유하는 실트암과 실트질 이암으로 이루어져 있으며, 암석코어의 조직과 퇴적구조에 따라 균질상(HM), 평행엽층리상(PL), 사엽층리상(XL), 희미한 엽층리상(IL), 생교란상(BT), 변형상(DF) 등 6개의 퇴적상이 구분된다. 몬트니층의 전반적인 퇴적상의 구성은 상부와하부 구간에서 대조적으로 나타나는데, 하부 몬트니층에서는 점토광물과 유기물의 함량이 상부 몬트니층에 비해 다소 높게 나타나며, 안정적이고 지속적인 저에너지 환경을 지시하는 퇴적상이 우세하다. 반면에 상부 몬트니층의 퇴적상은 고에너지 수층운동(파도, 폭풍)에 의한 퇴적, 침식, 변형 구조, 그리고 퇴적 후의 생물교란에의한 구조 등을 특징으로 하고 있다. 따라서 몬트니층이 형성되는 동안, 퇴적환경은 상대적 해수면의 하강으로인해 폭풍파 기저면 하부의 외해 혹은 심해에서 파도와 폭풍의 영향이 우세한 폭풍파 기저면 상부의 대륙붕 연안 환경으로 점차 변화된 것으로 해석된다. The Montney Formation in the western Alberta, Canada, is a gas-bearing sedimentary deposit of the early Triassic in age. For the understanding of the sedimentological diversity of source rock reservoirs as a major controlling factor of fracturing efficiency during the shale gas development, this study focuses on sedimentary processes and depositional environments of the Montney Formation (MF) based on sedimentary facies analysis of rock cores (about 200 m in total length) from the Kakwa well. The main lithology of the formation includes siltstones and silty mudstones consisting dominantly of silicate minerals (quartz and felspar) averaging approximately 60% (by weight). Six sedimentary facies were identified on the basis of centimeter-scale description of sedimentary structures and texture in borehole cores: homogeneous mudstone (HM), parallel-laminated mudstone (PL), cross-laminated mudstone (XL), indistinctly laminated mudstone (IL), bioturbated mudstone (BT) and deformed mudstone (DF). The overall occurrence of sedimentary facies shows a distinct contrast between the upper and lower parts of the formation. In the lower MF, contents of clay minerals and organic matters are relatively high, and sedimentary facies are suggestive of persistent hemipelagic sedimentation under the stable and low energy environments. The upper MF, on the other hand, consists of diverse sedimentary facies formed by wave- or storm-induced sedimentation, erosion and deformation as well as bioturbation in high energy environments. During the deposition of the MF, the depositional site has experienced an relative sea-level fall changing from offshore or deeper seafloor below the storm wave base to nearshore in a wave- and storm-dominated continental shelf.

Seismic stratigraphy of the Central Basin in northwestern Ross Sea slope and rise, Antarctica: Clues to the late Cenozoic ice-sheet dynamics and bottom-current activity

Kim, Sookwan,De Santis, Laura,Hong, Jong Kuk,Cottlerle, Diego,Petronio, Lorenzo,Colizza, Ester,Kim, Young-Gyun,Kang, Seung-Goo,Kim, Hyoung Jun,Kim, Suhwan,Wardell, Nigel,Geletti, Riccardo,Bergamasco, Elsevier 2018 Marine geology Vol.395 No.-

<P><B>Abstract</B></P> <P>Sedimentation processes influenced by late Cenozoic ice-sheet dynamics and bottom-current activity can be extracted from the seismic stratigraphic record of the Ross Sea continental slope and rise, where more continuous sedimentary successions are preserved compared to the continental shelf. In this study, we present a seismic stratigraphic analysis of the Central Basin that lies in the northwestern Ross Sea, using newly acquired and existing legacy seismic reflection data that are correlated to adjacent scientific drill sites. The chronostratigraphy of Ross Sea seismic sequences lying above the mid-Miocene sequence boundary (RSU4, ca. 16.5–15.5Ma) is based on the former Antarctic Offshore Stratigraphy (ANTOSTRAT) project. Depth-contour and isopach maps of sedimentary sequences bounded by two major unconformities of RSU4 and RSU2 (the late Pliocene boundary, ca. 4.0–2.8Ma) and the present-day seafloor were produced to illustrate the evolution of paleo-seafloor morphology, distribution of sediments and depocenter migration in the western Ross Sea outer margin.</P> <P>The results of seismic stratigraphic analysis indicate that gravity sedimentation processes dominated the Central Basin infill up to the mid-Miocene, and then downslope sediment supply gradually diminished through the late Miocene and Quaternary, likely reflecting a shift toward a cooler, less erosive glacial regime change. Since the late Pliocene, a topset-truncated glacial prograding wedge developed in the upper continental slope at the mouth of the Joides Basin and the sediment depocenter was shifted from the basin floor to the upper slope, suggesting the more persistent occurrence of grounded ice sheets on the outer continental shelf. Meanwhile, persistent along-slope bottom-current processes formed contourites on the slope and over the crests of banks surrounding the Central Basin since the mid-Miocene. In the late Pliocene, the contourites that formed off the Joides Basin mouth were overlain by glaciogenic debris flows, while the growth of contourites continued over and along the flanks of banks, farther to the north. This suggests that along-slope bottom-current processes near the Joides Basin mouth were diminished or dominated by the glacial discharge to the continental shelf edge. The sediment stacking patterns differ between the Joides/Central Basins and the Drygalski/Adare Basins located on the westernmost Ross Sea margin, suggesting that distinctive glacial/interglacial behavior of the former grounded ice streams and sediment supplies in the troughs feeding these basins were largely controlled by the paleo-seafloor morphology of the western Ross Sea continental shelf.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First seismic stratigraphic analysis of the Central Basin, northwestern Ross Sea. </LI> <LI> Gravity and bottom-current controlled sedimentary features are observed. </LI> <LI> Distinctive paleo-seafloor morphology and depocenter migration are indicated. </LI> <LI> Ice sheet shifted toward polar-style glacial regime during the late Cenozoic. </LI> <LI> Bottom-current activity changed near the paleo-shelf edge after late Pliocene. </LI> </UL> </P>

Sedimentary facies and volcanic activities of the Cretaceous Gongju Basin

정대교(Daekyo Cheong) 대한지질학회 2002 지질학회지 Vol.38 No.1

SEDPAK sedimentary simulation for the sediments of Lake Hovsgol, Mongolia: Interpretation of sedimentary processes, lake-level fluctuations, and burial history

차지만(Jiman Cha),정대교(Daekyo Cheong) 대한지질학회 2012 지질학회지 Vol.48 No.3

남극 브랜스필드 해협에서의 퇴적과정과 관련된 기후특성

이방용 ( Bang Yong Lee ),권태영 ( Tae Yong Kwon ),이정순 ( Jeong Soon Lee ),윤호일 ( Ho Il Yoon ),윤영준 ( Young Jun Yoon ) 대한지구물리학회 2005 지구물리 Vol.8 No.4

한반도 서해남부 임자도 해빈 퇴적작용의 계절적 변화

류상옥,장진호,조주환,문병찬 한국해양학회 2004 바다 Vol.9 No.3

한반도 서해남부 임자도 해빈에서 퇴적작용의 계절적 변화를 규명하기 위하여 2년 동안 지형 단면과 표층퇴적물, 집적률에 대한 모니터 링을 실시하였다. 해빈 단면은 경사가 급한 해빈면과 비교적 경사가 완만한 중ㆍ저조해빈으로 이루어져 있다. 해빈면의 경사는 여름에 증가하고 겨울에 감소하여 일반적인 해빈의 계절순환 양상과 잘 일치된다. 또 한 중ㆍ저조해빈은 여름에는 파봉과 유흔구조가 잘 발달하는데 반해, 겨울에는 메가 연흔이 잘 발달하는 계절적 변화를 보인다. 해빈 퇴적물은 해빈의 북측에서 남측으로, 그리고 저조선에서 고조선 방향으로 세립해지는 경향을 보인다. 퇴적물의 평균 입도는 북측 해빈에서는 가을과 겨울에 조립해지는데 반해, 남측 해빈에서는 겨울과 봄에 조립해지는 경향을 보인다. 또한 집적률 조사 결과, 북측 해빈은 전체적으로 침식되고 남측 해빈은 퇴적되는 양상을 보인다. 이와 같은 현상은 해빈 퇴적물이 해안선 방향(북동-남서)으로 발달하는 연안류에 의해 해빈을 따라 남쪽으로 이동하기 때문으로 생각된다. 그러나 집적률의 계절적 변화는 매우 복잡할 뿐 아니라 뚜렷한 규칙성을 보이지 않는다. 이는 아마도 인위적 요인에 의한 연안 및 해저지형 변화와 지구온난화에 따른 해수면 상승 등 다양한 요인들에 의해 임자도 해빈의 에너지 수준이 평행상태에 도달하지 못하고 불안정한 상태에 있음을 의미하는 것으로 생각된다. A continuous monitoring of textural characteristics of surface sediments, sedimentation rates and beach profile was carried out to investigate the seasonal variations of sedimentary processes in the Imjado beach, southwestern coast of Korea for two years. The beach profiles consist of steep beach face and relatively flat middle and low tide beaches. The slope of the beach face increases in summer and decreases in winter, in good accordance with the standard beach cycle. Ridge and runnel systems are well developed in the middle and low tide beaches during the summer, but these structures are replaced by mega-ripples during the winter. The sediments are fining southward as well as landward. The mean grain-size tends to be increasingly coarser during seasons of autumn and winter on the north beach and during seasons of winter and spring on the south one. In addition, the sediments are eroded on the north beach and accumulated on the south one as a whole. These are probably due to southward transportation of the sediments as long-shore current (NE-SW) runs around the coastal line of the beach. However, the seasonal variations in accumulation rates are very complex and irregular. It is considered that the Imjado beach represents in non-equilibrium state, as a result of coastal and submarine topographic changes by artificial agents and sea-level uprising associated with global warming.

동해 한국대지 및 울릉 분지간통로의 제4기 후기 해저퇴적작용

윤석훈,박장준,한상준 한국해양학회 2003 바다 Vol.8 No.2

한국대지와 인근 울릉 분지간통로에 분포하는 플라이스토세 후기 퇴적층에 대한 Chirp 방식 고해상 지층탐사 자료의 탄성파상과 피스톤 코아 시료의 퇴적상 분석을 통하여 해저 퇴적작용을 규명하였다. 한국대지는 한반도와 분리된 해저고지대로서 육성 퇴적물 유입이 매우 제한되어 있으며, 한국대지 사면에는 불규칙한 돌출지형과 함께 다양한 규모의 해저협곡이나 해저계곡이 형성되어 있다 완경사의 한국대지 대부분 지역에는 화산기원 퇴적물이 협재 하는 (반)원양성 퇴적물이 우세하게 집적되어 있으며, 한국대지 사면과 해릉 및 해산의 급경사 부분에서는 이들 퇴적물이 슬럼프, 슬라이드, 암설류 등 해저사태에 기인한 질량류로 재동되어 함몰흔적과 함께 나타난다. 재동된 퇴적물은 점토가 우세한 조직 특성과 사면의 급경사 때문에 저탁류보다는 부유입자가 우세한 고농도 수층의 형태로 전이되어 해저협곡을 통해 울릉분지평원으로 이동된 것으로 보인다. 울릉분지간통로 지역은 통상적인 (반)원양성 침전과 주로 오키뱅크와 독도 사면에서 해저수로를 통해 유입되는 간헐적인 저탁류와 암설류가 주된 퇴적작용의 역할을 하였으며, 이와 함께 일본분지로부터 유입되는 심층수의 영향으로 분지간수로와 그 주변 해저에 분포하는 퇴적물이 활발히 침식되어 재동된 것으로 보인다. High-resolution (Chirp, 3-11 kHz) echo facies and sedimentary facies of piston-core sediments were analyzed to reveal the late Quaternary depositional processes in the Korea Plateau and Ulleung Interplain Gap. The Korea Plateau is an Isolated topographic high with a very restricted input of terrigenous sediments, and its slope is characterized by a thin sediment cover and various-scale submarine canyons and valleys. Echo and sedimentary facies suggest that the plateau has been moulded mainly by persistent (hemi) pelagic sedimentation and intermittent settling of volcanic ashes. Sediments on the plateau slope and steep margins of ridges and seamounts were reworked by earthquake-induced, large-scale slope failures accompanied by slides, slumps and debris flows. As major fraction of the reworked sediments consists of (hemi) pelagic clay particles, large amounts of sediments released from mass flows were easily suspended to form turbid nepheloid layers rather than bottom-hugging turbidity currents, which flowed further downslope through the submarine canyons and spreaded over the Ulleung Basin plain. In the Ulleung Interplain Gap, sediments were introduced mainly by (hemi) pelagic settling and subordinate episodic mass flows (turbidity currents and debris flows) along the submarine channels from the slopes of the Oki Bank and Dok Island. The sediments in the Ulleung Interplain Channel and its margin were actively eroded and reworked by the deep water flow from the Japan Basin.

전황함량과 순산발생능력의 상관관계를 통한 잠재특이산성토양 기준 설정

문용희(Yonghee Moon),장용선(Yong-Seon Zhang),현병근(Byung-Keun Hyun),손연규(Yeon-Kyu Sonn),박찬원(Chan-Won Park),송관철(Kwan-Cheol Song) 한국토양비료학회 2012 한국토양비료학회지 Vol.45 No.6

황철석 (Pyrite, FeS₂)을 함유한 잠재특이산성토는 강하류 삼각지 토양, 간척지 등의 해성토뿐만 아니라, 영일만과 같은 융기해성토 지대, 내륙의 선상지하단 유기물이 많은 암흑색 토층이 있을 때에 존재하는 수가 있다. 또한 안산암지역의 열수작용에 의해 생성되어 암맥을 따라 형성된 황철석이 광산개발이나 도로건설로 절취사면에서 노출되어 산화되면 매우 강한 산성을 띠는 특이산성토층을 형성하여 주변농경지에 피해를 주고 있다. 현재 잠재특이산성토양의 판정은 현장에서는 과산화수소로 반응 시 수증기발생 정도로 판단하거나 실내실험에서는 전황 (Total-S)성분의 함량으로 판단한다. 하지만 이들 방법은 시군농업기술센터 및 현장 진단 시 적용이 용이하지 않다. 산발생 능력평가 중 순산발생능력실험 (Net Acid Generation, NAG pH)은 대상지역의 산성발생 가능성에 대한 예측을 정량적 계산으로 가능하다. 순산발생능력실험을 이용하여 전황함량과 NAG pH와의 상호관계를 통해 특이산성토양 판정을 제안하기 위해 화산기원의 잠재특이산성 토양과 사양질 토양을 일정비율로 혼합된 토양과 특이산성토양인 김해통과 해척통 토양에 대해 실험을 수행하였다 전황의 함량이 0.75% 이상인 시료의 NAG pH가 2.5이며 0.75-0.50%의 중간 특이산성토양은 NAG pH 3.0으로 측정되었다. 그리고 전황 함량이 0.5-15% 약한 특이산성 토양은 NAG pH 3.8로 측정되었다. 따라서 순산발생량은 NAG pH를 이용하여 토양 내 황철석을 모두 산화시키고 pH를 측정하여 pH 3.8이하인 토양은 특이산성토양으로 구분하는 것이 타당할 것으로 판단되었다. Acid sulfate soil (ASS) and potential acid sulfate soil (PASS) are distribution in worldwide and originate from sedimentary process, volcanic activity, or metamorphism and are problematic in agriculture and environmental due to their present and potential acidity developed by the oxidation. The PASS was defined as soil materials that had sulfidic layer more than 20 cm thick within 4 m of the soil profile and contained more than 0.15% of total-sulfur (T-S). A tentative interpretative soil classification system was proposed weak potential acid sulfate (T-S, 0.15-0.5%), moderate potential acid sulfate (T-S, 0.5-0.75%) and strong potential acid sulfate (T-S, more than 0.75%). PASS due to excess of pyrite over soil neutralizing capacity are formed. It provides no information on the kinetic rates of acid generation or neutralization; therefore, the test procedures used in acid base account (ABA) are referred to as static procedures. The net acid generation (NAG) test is a direct method to measure the ability of the sample to produce acid through sulfide oxidation and also provides and indication. The NAG test can evaluated easily whether the soils is PASS. The samples are mixed sandy loam and the PAS from the hydrothermal altered andesite (1:3, 1:8, 1:16, 1:20, 1:40, 1:80 and 1:200 ratios) in this study. We could find out that the NAG pH of the soil containing 0.75% of T-S was 2.5, and that of the soil has 0.15% of T-S was 3.8. NAG pH test can be proposed as soil classification criteria for the potential acid sulfate soils. The strong type has NAG pH of 2.5, the moderate one has NAG pH of 3.0, and the weak one has NAG pH of 3.5.