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Middle Cambrian trilobites from the Daegi Formation, the Seokgaejae section. Scale bars are 1mm long. (a)–(f) Ammagnostus laiwuensis (Lorenz, 1906). (a) SNUP3501, testaceous cephalon, DH3. (b) SNUP3502, testaceous cephalon, DH3. (c) SNUP3503, exfoliated cephalon, DH5. (d) SNUP3504, testaceous pygidium, DH3. (e) SNUP3505, mostly exfoliated pygidium, DH5. (f) SNUP3506, mostly exfoliated pygidium, DH5. (g)–(h) Ammagnostus sp. (g) SNUP3507, exfoliated cephalon, DH6. (h) SNUP3508, partly exfoliated pygidium, DH6. (i)–(p) Dorypyge richthofeni Dames, 1883. (i) SNUP3509, partly exfoliated cranidium, DH5. (j) SNUP3510, testaceous cranidium, DH5. (k) SNUP3511, exfoliated cranidium, DH5. (l) SNUP3512, lateral view of partly exfoliated cranidium, DH5. (m) SNUP3513, mostly exfoliated hypostome, DH5. (n) SNUP3514, partly exfoliated pygidium, DH5. (o) SNUP 3515, exfoliated pygidium, DH5. (p) SNUP3516, partly exfoliated pygidium, DH5.
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The Daegi Formation in the Taebaeksan Basin of Korea is composed of shallow marine carbonate facies and has been known to
yield relatively diverse invertebrate fossils of middle Cambrian age. This paper describes seventeen trilobite species belonging
to fifteen genera from the Daegi Formation exposed in the Seokgaejae section, located at southeaste...
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The brachiopod fauna of the upper Cambrian (upper Furongian) Guole Formation, northwestern Jingxi County, southwestern Guangxi Province, southern China, comprises six genera and seven species, including one new genus, three new species and two indeterminate species (Obolidae gen. et sp. indet, Acrotretidae gen. et sp. indet., Billingsella guangxien...
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... It reflects a prolonged second-order cycle of marine transgression and regres-sion . Numerous lithostratigraphic, biostratigraphic, and sequence-stratigraphic studies from the last two decades have contributed significantly to the understanding of these early Palaeozoic sedimentary sequences and their palaeoenvironments, palaeogeography, sedimentary processes, biostratigraphy, palaeoecology, and diversity (e.g., S.B. Lee et al., 2004Lee et al., , 2005Lee et al., , 2006Lee et al., , 2008S.B. Lee andD.K. Choi, 2007, 2011;Kwon et al., 2002Kwon et al., , 2003Kwon et al., , 2005Kwon et al., , 2006 Jeong and Y.I. Lee 2004; Y. Kim and Y.I. Lee, 2006; I. Kang and D.K. Choi, 2007; T.-Y. Park and D.K. Choi, 2010a, b, 2011McKenzie et al., 2011;Chen et al., 2012;Hong et al., 2012Hong et al., , 2014Hong et al., , 2015Hong et al., , 2016T.-Y. Park et al., 2012Choh et al., 2013;Kihm et al., 2013;T.-Y. Park and Kihm, 2015;D.K. Choi et al., 2016;J.-H. Lee et al., 2016bJ.-H. Lee et al., , 2021J.-H. Lee et al., , 2023M. Lee et al., 2016;D.K. Choi and T.Y.S. Park, 2017;Jeon et al., 2019;H.S. Kim et al., 2019;Bang and Y.I. Lee, 2020;Byun et al., 2020;E. Cho et al., 2021;H. ...
... In addition, the Crepicephalina Zone, which is the basal biozone of the overlying Daegi Formation (I. Kang and D.K. Choi, 2007), indicates the early Drumian age in both Taebaek and North China (D.K. Choi et al., 2016;Peng, 2020). Therefore, although it is not clear when the sedimentation of the Myobong Formation began, it can be inferred that the formation was deposited during Cambrian Age 4 to the Wuliuan. ...
... In North China and Korea, fine-grained siliciclastic-dominant successions that conformably overlie basal units are themselves overlain by shallow carbonate formations (Zhangxia in Shandong; Daegi in Taebaek) (Fig. 13) (D.K. Chough, 2013;Hong et al., 2012Hong et al., , 2016Woo et al., 2018). In both areas, the Crepicephalina trilobite biozone recorded in the lowermost carbonates suggests a moreor-less simultaneous transition (D.K. Choi et al., , 2016; I. Kang and D.K. Choi, 2007;Woo et al., 2018), and similar depositional models have been created for both areas Woo et al., 2018). For example, both successions contain abundant Epiphyton-dominant reefs with lithistid sponges (Woo et al., 2008(Woo et al., , 2018Adachi et al., 2015;Hong et al., 2016;J.-H. Lee et al., 2016a;E. ...
The lithostratigraphic relationships among the basal Taebaek Group, including the Jangsan, Myeonsan, and Myobong formations, have been controversial until recently. It has long been assumed that the Jangsan and Myeonsan formations are lateral equivalents that are both conformably overlain by the Myobong Formation. However, recent studies have shown that the Jangsan is Precambrian in age and is unconformably overlain by the Cambrian succession, whereas the Myeonsan is a Cambrian unit. Accordingly, this study proposes a revised lithostratigraphic framework of the basal Taebaek Group. The Myeonsan Formation (Cambrian Age 3?) is defined here as a basal Cambrian succession consisting of a basal conglomerate and coarse-grained immature sandstone with detrital heavy minerals that unconformably overlies Precambrian basement. The Myobong Formation (~Cambrian Age 4–Wuliuan) is a fine-grained unit that conformably overlies the Myeonsan Formation. The Myobong is subdivided as follows: Seokpo Member of lenticular cross-laminated sandstone and siltstone; Daehyun Member of laterally continuous alternations of thin-bedded sandstone and siltstone with some carbonate-filled channels; Gurae Member of bioturbated sandstone. The Myeonsan Formation is comparable with lowermost Cambrian units in North China that formed during second-order transgression. Further sea-level rise led to the deposition of the Myobong Formation and its correlative units in North China.
... 이은수 · 이애진 · 박진오 · 홍종선 조가 우세한 바운드스톤으로 주로 구성되어 있으며 조하대 탄산염 램프-외해 대륙붕 퇴적층으로 해석되 었다 (Kwon et al., 2006;Sim and Lee, 2006;Hong et al., 2016aHong et al., , 2016b. 대기층의 Crepicephalina, Amphoton, Jiulongshania 삼엽충 생층서대는 그 퇴적 시기가 울리우절(Wuliuan) 최후기~구장절(Guzhangian) 중기임을 지시한다 (Geyer and Shergold, 2000;Kang and Choi, 2007;Park et al., 2008). 대기층의 생물 초는 과거 경상북도 봉화군 석개재에서 보고되었으 며, 미생물-해면류 생물초와 미생물 크러스트 생물 초가 층 중-상부에 걸쳐 광역적으로 발달했다고 알 려져 있다 (Sim and Lee, 2006;Hong et al., 2012Hong et al., , 2016aHong et al., , 2016b Figure 3b showing a boundary (line) between a bioherm (Bts) and an inter-reef deposit (Di). ...
... ozakii", a junior synonym of Ammagnostus laiwuensis, is another means of correlation. A. laiwuensis occurs in Drumian and Guzhangian strata of South China and Korea (Kang and Choi, 2007;Peng et al., 2011), and the Guzhangian of Tasmania (Jago and Brown, 2001;Jago et al., 2004) and Laurentia Lerosey-Aubril et al., 2018). Arglina perrara has been previously reported from the Mayan (Miaolingian) of Turkestan, but with no further chronostratigraphic precision (Khajrullina 1970). ...
Recent reconnaissance geological mapping, identification of unconformities and chronostratigraphic dating of Miaolingian to Ordovician strata in the eastern Alborz Mountains have led to recognition of synsedimentary uplift episodes associated with block tilting and partial erosion of the Cambrian Mila and Ordovician Simeh Kuh, Qumes and Lashkarak formations. A chronostratigraphic revision of the Miaolingian-Late Ordovician fossil content is presented, and the Steptoean Positive Carbon Isotope Excursion (SPICE) chemostratigraphic shift, marking the Miaolingian–Furongian boundary, is constrained close to the Members 2/3 contact in the Mila Formation. Upper Ordovician basaltic lava flows embedded in the Abarsaj Formation and Devonian sills and dykes intruded in the Mila and Simeh-Kuh formations were geochemically analysed and compared with the voluminous lava eruptions recognized in the Katian-Llandovery Soltan-Maidan and Gorgan Schists formations, and in the ?Emsian-Eifelian Mighan Formation. They represent successive magmatic pulses of alkaline to subalkaline activities, separated by background (quiescent) intervals of up to 35 m.y., characterizing an intraplate field (continental rift) affinity compatible with OIB-like (ΔNb>0) mantle sources. Successive Miaolingian-Mid Ordovician (volcanic-free) uplift episodes were related to lithospheric doming preceding the onset of stepwise plume-related rift pulses, which shaped a large igneous province with transects of about 600 km, linking the Damghan and Alestan domains of the eastern Alborz Mountains with South Kopet-Dagh and some blocks of Central Iran.
... Cambrian and Ordovician carbonate formations occur in the Taebaek and Jeongseon areas located in the central-eastern part of the Korean peninsula ( Figure 1). These formations have been steadily investigated in various fields such as carbonate depostional Kang and Choi [17]. Locations of samples are marked with a red star. ...
... The stratigraphy differs little from that of the Taebaek area, except for the presence of the "Hoedongri" Formation. The "Hoedon- Kang and Choi [17]. Locations of samples are marked with a red star. ...
... Among these, the Daegi Formation mostly consists of carbonates, and it is widely distributed throughout the central-eastern part of the Korean Peninsula, including the Jeongseon, Samcheok, and Taebaek areas ( Figure 1). The Daegi Formation is known to have been deposited in a shallow marine environment such as a platform margin [13,16,17]. Kim and Park [13] suggested that the Daegi Formation was deposited at a depth shallower than 10 m below sea level. ...
Carbonate formations of the Cambro-Ordovician Period occur in the Taebaek and Jeongseon areas, located in the central–eastern part of the Korean Peninsula. This study analyzed the rare earth element (REE) contents and Sr–Nd isotope ratios in these carbonates to elucidate their depositional environment and diagenetic history. The CI chondrite-normalized REE patterns of the carbonates showed negative Eu anomalies (EuN/(SmN × GdN)1/2 = 0.50 to 0.81), but no Ce anomaly (Ce/Ce* = CeN/(LaN2 × NdN)1/3 = 1.01 ± 0.06). The plot of log (Ce/Ce*) against sea water depth indicates that the carbonates were deposited in a shallow-marine environment such as a platform margin. The 87Sr/86Sr ratios in both Taebaek and Jeongseon carbonates were higher than those in the seawater at the corresponding geological time. The 87Sr/86Sr ratios and the values of (La/Yb)N and (La/Sm)N suggest that the carbonates in the areas experienced diagenetic processes several times. Their 143Nd/144Nd ratios varied from 0.511841 to 0.511980. The low εNd values and high 87Sr/86Sr ratios in the carbonates may have resulted from the interaction with the hydrothermal fluid derived from the intrusive granite during the Cretaceous Period.
... ozakii", a junior synonym of Ammagnostus laiwuensis, is another means of correlation. A. laiwuensis occurs in Drumian and Guzhangian strata of South China and Korea (Kang and Choi, 2007;Peng et al., 2011), and the Guzhangian of Tasmania (Jago and Brown, 2001;Jago et al., 2004) and Laurentia Lerosey-Aubril et al., 2018). Arglina perrara has been previously reported from the Mayan (Miaolingian) of Turkestan, but with no further chronostratigraphic precision (Khajrullina 1970). ...
... The Crepicephalina Zone occurs in the lower 30-mthick interval of the Daegi Formation in the Seokgaejae section (Kang and Choi, 2007). It comprises 10 trilobite species including Ammagnostus laiwuensis (Lorenz, 1906), Dorypyge richthofeni Dames, 1883, Anomocarella temenus (Walcott, 1905), a ptychopariid species, Changqingia deprati (Kobayashi, 1935), Crepicephalina damia (Walcott, 1905), Proasaphiscus sp., Manchuriella macar (Walcott, 1911), Ignotogregatus sp. ...
... The Jiulongshania Zone was originally proposed as the Cyclolorenzella Zone based on Cyclolorenzella rotundata (Resser and Endo, 1937) which occurs in the uppermost 5m-thick interval of the Daegi Formation in the Seokgaejae section (Kang and Choi, 2007). However, Park et al. (2008) demonstrated that C. rotundata is morphologically distinct from the type species of Cyclolorenzella and belongs to Jiulongshania Park et al., 2008, and subsequently the Cyclolorenzella Zone has been renamed as the Jiulongshania Zone. ...
... sp. (Kang and Choi, 2007). The Jiulongshania Zone of the Sesong Formation yields a comparatively diverse trilobite assemblage including Jiulongshania longispina (Wittke and Zhu in Zhu and Wittke, 1989), J. regularis (Walcott, 1906), Bergeronites ketteleri (Monke, 1903), Teinistion lansi Monke, 1903, Teinistion sp., Blackwelderia spp., Liostracina sp. ...
In Korea, trilobites are among the most intensively studied fossil groups in the past century and provide invaluable information about lower Paleozoic stratigraphy, paleogeography, and tectonics of the Korean Peninsula. Trilobites occur in the lower Paleozoic Joseon Supergroup of the Taebaeksan Basin which was part of the Sino-Korean Craton in the Paleozoic. The Joseon Supergroup is divided into the Taebaek, Yeongwol, and Mungyeong groups. The Taebaek and Yeongwol groups are richly fossiliferous, while the Mungyeong Group is poorly fossiliferous. Contrasting trilobite faunal contents of the Taebaek and Yeongwol groups resulted in two separate biostratigraphic schemes for the Cambrian–Ordovician of the Taebaeksan Basin. A total of 22 biozones or fossiliferous horizons were recognized in the Taebaek Group; 19 zones were established in the Yeongwol Group; and four biozones were known from the Mungyeong Group. These trilobite biozones of the Taebaeksan Basin indicate the Joseon Supergroup ranges in age from the Cambrian Series 2 to Middle Ordovician and can be correlated well with the formations of North China, South China, and Australia.
... The Daegi Formation (150-250 m thick), the lowest carbonate-dominant unit of the Taebaek Group, is composed of shale and nodular limestones in lower part and ooid and bioclastic limestones in the middle to upper part, and is interpreted as off-platform to shallow subtidal platform deposits, respectively (Choi et al., 2004;Kwon et al., 2006;Sim and Lee, 2006;Hong et al., in press). The identification of Crepicephalina, Amphoton, and Jiulongshania trilobite biozones in the formation indicates a late Stage 5-middle Guzhangian age (Geyer and Shergold, 2000;Kang and Choi, 2007;Park et al., 2008;Peng et al., 2012) (Fig. 1B). ...
... The first trilobite biostratigraphic scheme for the Taebaek Group, established by Kobayashi (1935Kobayashi ( , 1966, was accepted for decades without significant modification, although many of the biozones were erected on the basis of a few poorly preserved specimens. However, the discovery of weathered out (exhumed) silicified trilobites from the Taebaek Group has led to the revision of some trilobite biozones (Choi et al., 2003, Kang & Choi 2007, Sohn & Choi 2007, Lee & Choi 2007. Moreover, recent studies using acid-extracted silicified trilobites have begun to revise the biostratigraphy of the Taebaek Group (Park & Choi 2011b, Park et al., 2012. ...
Park, T.-Y.S. & Kihm, J.-H., 3.10.2014. Furongian (late Cambrian) trilobites from the Asioptychaspis subglobosa Zone of the Hwajeol Formation, Korea. Alcheringa 39, xxx–xxx. ISSN 0311-5518The Hwajeol Formation of the Taebaek Group, Korea extends from the Jiangshanian Stage to Cambrian Stage 10. The lower part of the formation incorporates the Asioptychaspis Zone, which is closely correlated to the Asioptychaspis–Tsinania Zone of North China. This study documents silicified trilobites from the lower part of the Hwajeol Formation in the Sagundari section. Asioptychaspis subglobosa occurs throughout the interval; hence the biozone is renamed as the Asioptychaspis subglobosa Zone in this study. The Asioptychaspis subglobosa Zone of the Hwajeol Formation yields 14 polymerid species belonging to 14 genera. Of these, 11 species including three new species are documented for the first time in Korea. Among other taxa, the occurrence of Caznaia is stratigraphically significant because two biozones were established in Australia based on representatives of this genus: i.e., the Rhaptagnostus clarki patulus–Caznaia squamosa–Hapsidocare lilyensis and Rhaptagnostus clarki prolatus–Caznaia sectatrix zones in ascending order. Owing to the lack of cosmopolitan trilobites, the international correlation of these Iverian biozones has been equivocal. The occurrence of Caznaia from the Asioptychaspis subglobosa Zone of Korea indicates that the Rhaptagnostus clarki patulus–Caznaia squamosa–Hapsidocare lilyensis and Rhaptagnostus clarki prolatus–Caznaia sectatrix zones of Australia are correlated with the Asioptychaspis subglobosa Zone of Korea and the Asioptychaspis–Tsinania Zone of North China.Tae-Yoon S. Park [[email protected]
/* */] and Ji-Hoon Kihm [[email protected]
/* */] (corresponding author), Division of Polar Earth-System Sciences, Korea Polar Research Institute, Incheon 406-840, Korea.
... The Yeongwol and Taebaek groups yield relatively diverse and abundant invertebrate fossils such as trilobites, brachiopods, graptolites, gastropods and so on, whereas other three groups are poorly fossiliferous (Kobayashi, 1966; Choi et al., 2004). The Taebaek Group has been extensively studied in terms of litho-, bio-, and sequence stratigraphy (e.g., Choi et al., 2004; Kwon et al., 2006; Kang and Choi, 2007; Lee and Choi, 2007; Sohn and Choi, 2007; Park and Choi, 2011), the Yeongwol Group mainly in terms of paleontology (e.g., Sohn and Choi, 2002; Hong et al., 2003; Choi et al., 2004). Sedimentological research of the Yeongwol Group has been limited due to the complex tectonic structures, obliterated primary structures, and scanty number of outcrops. ...
Detailed study on the Lower Ordovician Mungok Formation in the mideastern part of the Korean peninsula has led to recognition of seven lithofacies which can be grouped into seven facies associations (FAs): FA1 (lagoon), FA2 (shoal), FA3 (shoreface), FA4 (inner to mid-ramp), FA5 (inner to outer ramp), FA6 (mid- to outer ramp), and FA7 (outer ramp). Spatio-temporal organization of the FAs represents homoclinal ramp environments with fringing ooidpeloid shoals. Correlation and lateral thickness variation of the FAs suggest that deep part of the basin might have been located toward the northern part of the study area. The relative sea-level curve inferred from the facies analysis suggests that the Mungok Formation evolved through three depositional stages in accordance with 3rd-order sealevel change. The organization of the facies succession indicates that the inner ramp facies associations (FA1 to 3) of the Mungok Formation are characterized by non-cyclic facies succession whereas the midand outer ramp facies associations (FA 4 to 7) have distinct cyclicity except non-cyclic FA 7. The difference in the facies successions between the inner ramp and the mid- to outer ramp area may result from the various depositional regime across a ramp. A non-cyclic facies successions of inner ramp facies (e.g., packstone to grainstone and lime mudstone) are suggestive of mosaic-type distribution that is controlled mostly by wave, storms, tides, currents, and local geomorphology. In contrast, cyclic facies successions (e.g., pebbly limestone conglomerate, limestone-shale alternation, and calcareous shale) represent a simple belt-type distribution of mid- to outer ramp facies that seems to reflect shifts of facies belt caused by sea-level changes. The partitioning of inner and mid- to outer ramp facies is appropriate for understanding the facies development of the Mungok Formation and similar ramp successions with distinct inner and mid- to outer ramp facies.
... The base of the Jiulongshania Zone should be defined at the FAD of J. rotundata at present, since the older species of Jiulongshania, such as J. acalle and J. longa (see Park et al., 2008b), have not been recovered from the Daegi Formation. It is noteworthy that J. rotundata is associated with Blackwelderia sp. in the Seokgaejae section, Korea (Kang and Choi, 2007), but Blackwelderia was not associated with J. rotundata in the Jiulongshan section, North China (Park et al., 2008b). Instead, the Jiulongshania species immediately preceding J. rotundata, J. acalle occurs in association with Damesella (Park et al., 2008b), the representative taxon of the Damesella-Yabeia Zone, which is overlain by the Blackwelderia Zone in North China. ...
