Sequence Stratigraphy Basics, Concepts & Applications
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Sequence Stragraphy - Basics, Concepts & Applicaons Sequence Stratigraphy Basics, Concepts & Applications 07.-09.03.2016 Dr. Hartmut Jäger Sequence Stragraphy - Basics, Concepts & Applicaons Introduction Books Posamen(er , H.W. & Weimer, P . (eds), 1994: Siliciclas/c Sequence Stragraphy: Recent Developments and Applicaons. (AAPG Memoir) Loucks, R.G. & Sarg, J.F., 1994: Carbonate Sequence Stragraphy: Recent Developments and Applicaons. (AAPG Memoir) Emery, D. & Myers, K., 1996: Sequence Stragraphy. Blackwell Science Catuneanu, O., 2006: Principles of Sequence Stragraphy (Developments in Sedimentology). Elsevier Haq, B.U., 2013: Sequence Stragraphy and Deposi/onal Response to Eustac, Tectonic and Climac Forcing. (Coastal Systems and Con/nental Margins). Springer Sequence Stragraphy - Basics, Concepts & Applicaons Introduction Stragraphy “the science of strafied (layered) rocks in terms of /me and space” (Oxford Dic/onary of Earth Sciences, 2003) Sequence "A chronologic succession of sedimentary rocks from older below to younger above, essen/ally without interrup/on, bounded by unconformi/es.” (Glossary of Geology, 1987) Sequence Stragraphy - Basics, Concepts & Applicaons Introduction Sequence stratigraphy is one type of lithostratigraphy • used for subdivision of the sedimentary basin fll by a framework of major depositional and erosional surfaces • creates units of contemporaneous accumulated strata bounded by these surfaces (=sequences) • developed for clastic and carbonate sediments from continental, marginal marine, basin margins and down-slope settings of basins. The • surfaces often generated during changes in relative sea level and formed during associated deposition and erosion. Sequence Stragraphy - Basics, Concepts & Applicaons Introduction - basic principles Sequence Stratigraphy is based on Steno's principles of sediment accumulation Sequence Stragraphy - Basics, Concepts & Applicaons Introduction - basic principles Sequence Stratigraphy is based on Walther's Facies Law – vertical and lateral equivalence of sediments Only those facies types and lithologies can be deposited on top of each other, which can be observed beside each other at one time level fluvial sands silty clay coastal plain terrigeneous muds coal swamp brackish muds shallow marine marine Limestones carbonates brackish mudstone coal lacustrine lagoon mudstone lacustrine limestone silty claystone sandstone Sequence Stragraphy - Basics, Concepts & Applicaons Introduction - Lithostratigraphy Lithostratigraphic units recognized and defned by lithic characteristics only, not by age. Hierarchy: Supergroup – Group – Formation – Member - Bed/Bed sets 2 types of contacts between units: conformable and unconformable. Conformable: continuous deposition, no break or hiatus (surface = conformity) Unconformable: period of erosion/non-deposition (surface = unconformity) Lithostratigraphical correlation based on lithofacies (using key beds or sequences) based on lithology, color, structure, thickness… Sequence Stragraphy - Basics, Concepts & Applicaons Lithostratigraphy Different types of lithostratigraphical frameworks conficting with sequence stratigraphy: • Lithostratigraphy (sensu strictu) • Allostratigraphy • Trangression-Regression Cycles • Stratigraphic Sequences • Seismo-Stratigraphy • Sequence Stratigraphy Sequence Stragraphy - Basics, Concepts & Applicaons Lithostratigraphy - Allostratigraphy Time dependent stragraphic framework Subdivision by /me equivalent surfaces/ layers: Transgressive/ regressive surfaces (erosional & marine flooding surfaces) also tuffites, tempes/tes, turbidites .... (marker beds) Sequence Stragraphy - Basics, Concepts & Applicaons Lithostratigraphy vs. Allostratigraphy Lithostratigraphic correlation – correlation of similar lithologies Allostratigraphic correlation – correlation of timelines but different lithologies (facies) Sequence Stragraphy - Basics, Concepts & Applicaons Lithostratigraphy - Transgressive-Regressive Cycles Time dependent stratigraphic framework organized by transgressive / regressive surfaces Sequence Stragraphy - Basics, Concepts & Applicaons Lithostratigraphy - Stratigraphic sequences Stratigraphic Sequences - assemblage of strata and formations bounded by prominent interregional unconformities Sloss et al. 1949 Subdivision of the Phanerozoic succession (blue) of N-America into six sequences (blue), limited by mes of non-deposion or erosion (yellow) Sloss 1963 Stragraphic sequences are based on transgressive / regressive cycles Sequence Stragraphy - Basics, Concepts & Applicaons Sedimentary Cycles Lithostragraphical correlaons are based on sedimentary cycles Several orders of sedimentary cycles – 0.01 to >100 my 1st-order cycles: Con/nental sequence 2nd-order cycles: Transgressive/regressive cycle 3rd-order cycles: Sequence cycle 4/5th order cycles: Parasequence cycle Sequence Stragraphy - Basics , Concepts & Applicaons Sedimentary Cycles Sedimentary Cycles Continental break-up Sea-floor spreading Eustatic (melting ice caps) Orogenesis and Rifting Local tectonical developments Milankovich cyclicity Climatic cycle Sequence Stragraphy - Basics, Concepts & Applicaons Sedimentary Cycles - 1st order cycles Con)nental-Cycle > 100 My Controlled by con/nental break up and formaon Phanerozoic 1st order eustac cycle linked to Precambrian (Rodinia or Proto-Pangea) and Permo-Triassic (Pangea) supercon/nents. 1st order eustac cycles are directly related to the volume of oceanic basins Cambrian Sequence Stragraphy - Basics, Concepts & Applicaons Sedimentary Cycles - 2nd order cycles Transgressive – regressive Cycle 10-100 My Mainly controlled by sea-floor spreading Sequence Stragraphy - Basics, Concepts & Applicaons Sedimentary Cycles - 3rd order cycles Sequence Cycle 1-10 My Regression Based on eustac sea-level changes Local to regional volcanic and tectonic events – riing, orogenesis, freezing/ melng of ice caps Changes to earth's shape, producing Transgression "bulges" or "sags" = ocean level fluctuaons. Sequence well logs iden/fied in lithological succession or shallowing Most and their correlave surfaces. bounded by marine flooding surfaces gene/cally related beds or relavely conformable succession of Parasequences ( the Caused by high-frequency changes in Parasequence Milankovich realitve Stragraphy parasequences -upward sedimentary cycles sea-level cycles - are defined as a Basics Cycle , climate , Sedimentary -4-5 Cycles Concepts are ) asymme/cal 0,01-1 & bedsets Applicaons My th order cycles ordercycles B ACHMANN nach nach & TST mfs HST A IGNER (1992) Sequenzen 3.Ordnung HST TST TST mfs mfs nach (1999) HST S HST ZUL C nach nach TST HST HST TST LST K (1999) HST HST Ę DZIERSK ( mf-Zone TST mfs LST mfs TST ) sb sb sb mfs I Sets Parasequenzen 6 7 8 4 3 5 1 2 so,m mu1 mu2 mu3 mu4 Steudnitz Gernrode Rüdersdorf Raciboro. St. Opolski Płaza Myophorien-Schichten/ Unterer Wellenkalk/ Oolithbänke - Mittlerer Wellenkalk/ Terebratelbänke Schaumkalkbänke/ Untere Gogolin-Sch. Obere Gogolin-Schichten Górażdże-Schichten - Oberer Wellenkalk Karchowice-Sch. Sequence Stragraphy - Basics, Concepts & Applicaons Sedimentary Cycles - 4-5th order cycles Parasequences Parasequence: A rela/vely conformable succession of gene/cally related beds or bedsets (within a parasequence set) bounded by marine flooding surfaces (Van Wagoner 1985). Paerns of the stacking of parasequence sets are used in conjunc/on with bounding surfaces and their posi/on within a sequence to define systems tracts (Van Wagoner et al. 1988). Sequence Stragraphy - Basics, Concepts & Applicaons Sedimentary Cycles - 4-5th order cycles Parasequences Sand-rich shoreline (deltaic systems): Muddy coastline: coarsening-upward succession, mud/sand cross-bedded sub/dal sands to mixed sediments (offshore) to sand mudstone/rippled sands alternaons dominated lower shoreface to pure sands (inter/dal) to en/rely bioturbated (coaly) of upper shoreface/foreshore mudstones (supradal). Sequence Stragraphy - Basics, Concepts & Applicaons Sedimentary Cycles - 4-5th order cycles shallowing upward cycle shallowing upward cycle shallowing upward cycle Sequence Stragraphy - Basics, Concepts & Applicaons Sedimentary Cycles - 4-5th order cycles shallowing upwards flooding surface shallowing upwards Camarillas, Maestrat Basin Sequence Stragraphy - Basics, Concepts & Applicaons An Online Guide to Sequence Stratigraphy Sedimentary Cycles - 4-5th order cycleshttp://strata.uga.edu/sequence/parasequences.html Parasequences figure adapted from Van Wagoner et al. (1990) - faciesBecause within a shallowparasequences water facies changes laterally, therefore a single within a parasequence will pinchparasequence out laterally will in a not be composed of the same downdip direction and deeperfacies water everywhere facies within a parasequence will pinch - composed of deeper water out in an updip direction,facies the facies downdip composition and shallower water of a single faciesparasequence updip - parasequencechanges predictably boundaries may become obscure in coastal plain sengs and in deep updip and downdip. Thus, a single parasequence will not marine sengs due to the lack of be composed of the same faciesfacies everywhere, contrast indicang flooding surfaces but will be composed of deeper water facies downdip and shallower water facies updip, as would be expected. Because parasequence boundaries represent a primary depositional surface, that is, topography at the time of deposition, flooding surfaces will tend to be relatively flat but dip slightly seaward at angles typical of continental shelves. Finally, parasequence