The sediments of the Cretaceous Gyeokpori Formation in south-western South Korea accumulated in a lake in which mainly siliciclastic rocks were deposited, with some interbedded volcaniclastics. The nearby volcanic activity resulted in unstable lake margins inducing a dominance of gravity-flow deposits. The high sedimentation rate facilitated soft-sediment deformation on the sloping margin. The deposition of numerous gravity-flow deposits resulted in a vertically heterolithic stratification. The slumps are composed of different lithologies, which is expressed in different types of deformation due to the difference in cohesion between sandy and mussy layers within the slumps. Coarser-grained (cohesionless) slumps tend to show more chaotic deformation of their lamination or layering. The difference in slumping behaviour of the cohesive and non-cohesive examples is explained and modelled.
A unique soft-sediment deformation structure is recognized. This structure has not been described before, and we call it ‘envelope structure’. It consists of a conglomerate mass that has become entirely embedded in fine-grained sediment because slope failure took place and the fine-grained material slumped down with the conglomerate ‘at its back’. The cohesive laminated mudstone formed locally slump folds that embedded the non-cohesive overlying conglomerate unit, possibly partly due to the bulldozing effect of the latter. This structure presumably can develop when the density contrast with the underlying and overlying deposits is exceptionally high. The envelope structure should be regarded as a special – and rare – type of a slumping-induced deformation structure.
If the inline PDF is not rendering correctly, you can download the PDF file here.
Abbate E. Bortolotti V. & Passerini P. 1970. Olistostromes and olistoliths. Sedimentary Geology 4 521–557.
Aber J.S. & Ber A. 2007. Glaciotectonism. Developments in Quaternary Science vol. 6. Elsevier Amsterdam 246 pp.
Alfaro P. Moretti M. & Soria J.M. 1997. Soft-sediment deformation structures induced by earthquakes (seismites) in Pliocene lacustrine deposits (Guadix-Baza Basin central Betic Cordillera). Eclogae Geologicae Helvetiae 90 531–540.
Allen J.R.L. 1982. Sedimentary structures: their character and physical basis Vol. II. Elsevier Amsterdam 663 pp.
Alsop G.I. Marco S. Weinberger R. & Levi T. 2016. Sedimentary and structural controls on seismogenic slumping within mass transport deposits from the Dead Sea Basin. Sedimentary Geology 344 71–90.
Bouma A.H. 1962. Sedimentology of some Flysch Deposits: A Graphic Approach to Facies Interpretation. Elsevier Amsterdam 168 pp.
Chough S.K. 2013. Geology and Sedimentology of the Korean Peninsula. Elsevier Amsterdam 348 pp.
Chough S.K. & Sohn Y.K. 2010. Tectonic and sedimentary evolution of a Cretaceous continental arc–backarc system in the Korean Peninsula: new view. Earth-Science Reviews 101 225–249.
Dehandschutter B. Vandycke S. Sintubin M. Vandenberghe N. & Wouters L. 2005. Brittle fractures and ductile shear bands in argillaceous sediments: inferences from Oligocene Boom Clay (Belgium). Journal of Structural Geology 27 1095–1112.
Gibert L. Sanz de Galdeano C. Alfaro P. Scott G. & Lopez Garrido A.C. 2005. Seismic induced slump in Early Pleistocene deltaic deposits of the Baza Basin (SE Spain). Sedimentary Geology 179 279–294.
Gibert L. Alfaro P. García-Tortosa F.J. & Scott G. 2011. Superposed deformed beds produced by single earthquakes (Tecopa Basin California): Insights into paleoseismology. Sedimentary Geology 235 148–159.
Gruszka B. & Van Loon A.J. 2011. Genesis of a giant gravity-induced depression (gravifossum) in the Enköping esker S. Sweden. [In:] Owen G. Moretti M. & Alfaro P. (Eds): Recognising triggers for soft-sediment deformation: current understanding and future directions. Sedimentary Geology 235 304–313.
Hempton M.R. & Dewey J.F. 1983. Earthquake-induced deformational structures in young lacustrine sediments East Anatolian Fault southeast Turkey. Tectonophysics 98 T7–T14.
Jiang J. Zhong N. Li Y. Xu H. Yang H. & Peng X. 2016. Soft sediment deformation structures in the Lixian lacustrine sediments eastern Tibetan Plateau and implications for postglacial seismic activity. Sedimentary Geology 344 123–134.
Kim S.B. Chough S.K. & Chun S.S. 1995. Bouldery deposits in the lowermost part of the Cretaceous Kyokpori Formation SW Korea: cohesionless debris flows and debris falls on a steep-gradient delta slope. Sedimentary Geology 98 97–119.
Kim S.B. Chough S.K. & Chun S.S. 2003. Tectonic controls on spatio-temporal development of depositional systems and generation of fining-upward basin fills in a strike-slip setting: Kyokpori Formation (Cretaceous) south-west Korea. Sedimentology 50 639–665.
Ko K. Park S. & Kwon C.W. 2015. Soft-sediment deformation structures in the Cretaceous Gyeokpori Formation of the Buan area Korea: Structural characteristics reconstruction of paleoslope and triggering mechanism of slump. Journal of Geological Society of Korea 51 545–560 (in Korean with English abstract).
Ko K. Kim S.W. Lee H.-J. Hwang I.G. Kim B.C. Kee W.-S. Kim Y.-S. & Gihm Y.S. 2017. Soft sediment deformation structures in a lacustrine sedimentary succession induced by volcano-tectonic activities: an example from the Cretaceous Beolgeumri Formation Wido Volcanics Korea. Sedimentary Geology 358 197–209.
Koh H.J. Kwon C.W. Park S.I. Park J. & Kee W.S. 2013. Geological report of the Julpo and Wido-Hawangdeungdo sheets (1:50000). Korea Institute of Geoscience and Mineral Resources 81 pp. (in Korean with English abstract).
Lowe D.R. 1982. Sediment gravity flows: II. Depositional models with special reference to the deposits of high-density turbidity currents. Journal of Sedimentary Petrology 52 279–297.
Martinsen O.J. 1989. Styles of soft-sediment deformation on a Namurian delta slope western Irish Namurian Basin Ireland. [In:] M.K.G. Whateley & K.T. Pickering (Eds): Deltas: sites and traps for fossil fuels. Geological Society London Special Publications 41 167–177.
Mills P.C. 1983. Genesis and diagnostic value of soft-sediment deformation structures – a review. Sedimentary Geology 35 83–104.
Moretti M. Alfaro P. & Owen G. 2016. The environmental significance of soft-sediment deformation structures: key signatures for sedimentary and tectonic processes. Sedimentary Geology 344 1–4.
Moretti M. & Sabato L. 2007. Recognition of trigger mechanisms for soft-sediment deformation in the Pleistocene lacustrine deposits of the Sant’Arcangelo Basin (southern Italy): seismic shock vs. overloading. Sedimentary Geology 196 31–45.
Mulder T. & Alexander J. 2001. The physical character of subaqueous sedimentary density currents and their deposits. Sedimentology 48 269–299.
Nemec W. & Steel R.J. 1984. Alluvial and coastal conglomerates: their significant features and some comments on gravelly mass-flow deposits. [In:] Koster E.H. & Steel R.J. (Eds.): Sedimentology of Gravels and Conglomerates. Memoir of the Canadian Society of Petroleum Geology 10 pp. 1–31.
Neuwerth R. Suter F. Guzman C.A. & Gorin G.E. 2006. Soft-sediment deformation in a tectonically active area: The Plio-Pleistocene Zarzal Formation in the Cauca Valley (Western Colombia). Sedimentary Geology 186 67–88.
Owen G. 1996. Experimental soft-sediment deformation: structures formed by the liquefaction of unconsolidated sands and some ancient examples. Sedimentology 43 279–293.
Pini G.A. 1999. Tectonosomes and olistostromes in the Argille Scagliose of the Northern Apennines Italy. Geological Society of America Special Paper 335 1–69.
Porębski. S.J. & Steel. R.J. 2003. Shelf-margin deltas: their stratigraphic significance and relation to deepwater sands. Earth-Science Reviews 62 283–326.
Raukas A. Tirmaa R. Kaup E. & Kimmel 2001. The age of the Ilumetsa meteorite craters in southeast Estonias. Meteoritics and Planetary Science 36 1507–1514.
Rodríguez-Pascua M.A. Calvo J.P. de Vicente G. & Gomez Gras D. 2000. Seismites in lacustrine sediments of the Prebetic Zone SE Spain and their use as indicators of earthquake magnitudes during the Late Miocene. Sedimentary Geology 135 117–135.
Rygel M.C. Gibling M.R. & Calder J.H. 2004. Vegetation-induced sedimentary structures from fossil forests in the Pennsylvanian Joggins Formation Nova Scotia. Sedimentology 51 531–552.
Sims J.D. 1973. Earthquake-induced structures in sediments of Van Norman Lake San Fernando California. Science 182 161–163.
Sims J.D. 1975. Determining earthquake recurrence intervals from deformational structures in young lacustrine sediments. Tectonophysics 29 141–152.
Talling P.J. Amy L.A. Wynn R.B. Peakall J. & Robinson M. 2004. Beds comprising debrite sandwiched within co-genetic turbidite: origin and widespread occurrence in distal depositional environments. Sedimentology 51 163–194.
Tanner L.H. & Lucas S.G. 2007. The Moenave Formation: Sedimentologic and stratigraphic context of the Triassic–Jurassic boundary in the Four Corners area southwestern USA. Palaeogeography Palaeoclimatology Palaeoecology 244 111–125.
Taşgın C.K. & Türkmen I. 2009. Analysis of soft-sediment deformation structures in Neogene fluvio-lacustrine deposits of Çaybağı Formation Eastern Turkey. Sedimentary Geology 218 16–30.
Taşgın C.K. Orhan H. Türkmen I. & Aksoy E. 2011. Soft-sediment deformation structures in the late Miocene Şelmo Formation around Adıyaman area Southeastern Turkey. Sedimentary Geology 235 277–291.
Tipper J.C. Sach V.J. & Heizmann E.P.J. 2003. Loading fractures and Liesegang laminae: new sedimentary structures found in the north-western North Alpine Foreland Basin (Oligocene-Miocene south-west Germany). Sedimentology 50 791–813.
Uchman A. Bak K. & Rodríguez-Tovar F.J. 2008. Ichnological record of deep-sea palaeoenvironmental changes around the Oceanic Anoxic Event 2 (Cenomanian-Turonian boundary): an example from the Barnasiówka section Polish Outer Carpathians. Palaeo-geography Palaeoclimatology Palaeoecology 262 61–71.
Van Loon A.J. 2009. Soft-sediment deformation structures in siliciclastic sediments: an overview. Geologos 15 3–55.
Van Loon A.J. 2002. Soft-sediment deformations in the Kleszczów Graben (central Poland). [In:] P.K. Bose S. Sarkar & P.G. Ericksson (Eds): Rift basins: sedimentology and palaeontology – Chanda Memorial Issue. Sedimentary Geology 147 57–70.
Williams G.E. Gostin V.A. McKirdy D.M. & Preiss W.V. 2008. The Elatina glaciation late Cryogenian (Marinoan Epoch) South Australia: Sedimentary facies and palaeoenvironments. Precambrian Research 163 307–331.
Wynn J.C. 1998. The day that sands got fire. Scientific American Magazine 279 64–71.
Yang R. & Van Loon A.J. 2016. Early Cretaceous slumps and turbidites with peculiar soft-sediment deformation structures on Lingshan Island (Qingdao China) indicating a tensional tectonic regime. Journal of Asian Earth Sciences 129 206–219.
Yang R. Van Loon A.J. Yin W. Fan A. & Han Z. 2016. Soft-sediment deformation structures in cores from lacustrine slurry deposits of the Late Triassic Yanchang Fm. (central China). Geologos 22 201–211.
Yang R. Fan A. Han Z. & Van Loon A.J. 2017. Lithofacies and origin of the Late Triassic muddy gravity-flow deposits in the Ordos Basin central China. Marine and Petroleum Geology 85 194–219.
Zhao L. Zhou Y. & Van Loon A.J. 2018. Soft-sediment deformation structures induced by rapid sedimentation in Early Cretaceous turbidites Lingshan Island eastern China. Canadian Journal of Earth Sciences 55 118–129.