Solar Affinity of Sedimentary Cycles in the Late Precambrian Elatina Formation

Williams, G. E.

doi:10.1071/ph851027

Cited by 37 publications

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“…Esse artigo e 0 resultado do estudo desses dois fenomenos indutores, da sua influencia nas oscilacoes e variacoes ciclicas climaticas e dos efeitos das ultimas na sedimentacao durante 0 Eopermiano na Bacia do Parana (Silva 2001). A metodologia de aquisicao dos dados para 0 estudo foi descrita em outro trabalho, denominado "Cicloestratigrafia do Eopermiano -Estudo de caso na Bacia do Parana (Parte I): uma metodologia pra preparacao de dados de perfil e rocha" (a partir deste ponto, CEOI-1), presente nesta mesma publicacao, Ao contrario dos ciclos orbitais, a influencia dos ciclos solares no clima e na sedimentacao, apesar de cada vez mais documentada na literatura (Anderson 1961, Eddy 1976, Williams 1985, Williams & Sonett 1985, Halfman & Johnson 1988, Fortes 1990, Ripepe & Fischer 1991, Fortes 1992, Anderson 1992, Schaaf & Thurow 1994e 1997, Lundqvist 1998, Von Rad et al 1999, ainda nao esta bern estabelecida e e alvo de controversias (Williams 1989, Gallet et al 2005. as geocientistas estao mais acostumados a trabalhar com processos de sedimentacao de depositos de mare e de varves, relacionados Cicloestratigrafia do Eoperm iano -estudo de caso no grup o Itarare, bacia do Parana (Parte 2): evkie ncies de indlll ; ao astron6mica (orbital e solar) no clima e na sedimentagao a inducoes astronomicas ciclicas nas escalas de um mes a lJlll ano, passando em seg uida para a escala dos ciclos orbitais, da ordem de 10 mil a 400 mil anos (estes sendo os mais comuns.…”

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Cicloestratigrafia Do Eopermiano - Estudo De Caso No Grupo Itararé, Bacia Do Paraná (Parte 2): Evidências De Indução Astronômica (Orbital E Solar) No Clima E Na Sedimentação

Silva

Filho

2005

RBG

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CYCLOSTRATIGRAPHY OF LOWER PERMIAN -CASE STUDY IN ITARARE GROUp, PARANA BASIN (PART II): EVIDENCES OF ASTRONOMIC FORCING (ORBITAL AND SOLAR) IN CLIMATE AND SEDIMENTATION -The existenceand natureof possibleastronomicforcingof cyclicityin glacialsedimentsof the ItarareGroup,Parana Basin,duringthe Eopermian,were studied in core and gamma ray log data from two wells drilled by CPRM (Companhiade Pesquisa de Recursos Minerais) to coal research,one in Santa Catarina and other in Rio Grande do SuI. The distancebetween the originallocation of the cores (about 380 km) made it possibleto test the astronomicforcing in this deposits in differentlocations of the basin.Two methodsof data sampling were used, accordingto data scaleand the possibleforcing: the gammaray logs were digitizedand sampledat I em intervals, in order to test the presence of orbital forcing (20,000 to 400,000 years) or other forcing phenomena (3,000 to 10,000years), andthe cores were scanned in the intervalswith rhythmites and transformed in gray scale data sampled equally (0,2538 mm), in order to search for annual to centennialcycles.The harmonicanalysis showed cyclicity in both scales: orbital cycles ranging from about 17,000to 100,000years and solar cyclesranging from about 22 to 1,000years. The accumulation time calculatedfor one well in log and core data (about 9,400years for the scannedintervaland about 12,600years for the same intervalin log data) showeda very high correlation. The accumulation rates calculatedfor the log data, ranging from 5,2 to 9,3 cm/ka, are very similarto the Pleistoceneones. The analysisalso showedthat the completesedimentaryrecord of the ItarareGroup for one of the wells corresponds to about half precession cycle (12,342years).As both astronomicforcingphenomenadetected, the solar and the orbitalcycles, affectclimate on a global scale, certainlytheir influence on sedimentation occurred in other locations of the basin.Keywords: cyclostratigraphy, Itarare Group, Lower Permian.Resumo A inducaoastronomica no clima da regiao da Bacia do Parana,durante0 Eopermiano, foi testada com 0 intuito de determinara naturezada ciclicidade presenteem sedimentos do Grupo Itarare,de origem glacial. Utilizaram-se dadosde testemunhos e de perfisde raios gama de dois pOyOS, urn em Santa Catarinae outro no Rio Grandedo Sui,perfuradospela CPRM.A distanciaentre as locacoesdos pOyOS (cerca de 380 km) possibilitou testar a influencia da inducaoastronomicaem localidades distintas. Dois metodos de amostragem foramutilizados, de acordocom a escalados dadose com a possivelinducao: perfisde raios gamaforam digitalizados e amostradosem intervalosde I em, para testara presencados ciclosorbitaisna escalade 20 mil a 400 mil anos, ou fenomenos indutores na escalade 3 mil a 10 mil anos, e os testemunhosforam escaneados nos intervalos com ritmitos e transformados em dados em escala de cinzaequiespacados (0,2538 mm), objetivando a busca por ciclos anuais a centenarios, A analise cicloestratigrafica sugere a presenca dos ciclos orbitais, com perfodosde cerca...

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Cicloestratigrafia Do Eopermiano - Estudo De Caso No Grupo Itararé, Bacia Do Paraná (Parte 2): Evidências De Indução Astronômica (Orbital E Solar) No Clima E Na Sedimentação

Silva

Filho

2005

RBG

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“…The rhythmites consist of 1-2 cmthick bundles of mm-scale couplets that were originally interpreted as varves deposited in a periglacial lake (Williams 1981), where each clastic lamina represents annual deposition of sediment by glacial meltwater (Williams 1981(Williams , 1985Williams and Sonett 1985). Williams (1985) argued that the periodic deposition of cyclic laminae correlated with sunspot cycles, though the mechanism by which Marinoan climate was controlled by sunspots was not clearly articulated. Furthermore, astronomical models suggest that the sunspot cycle during the Neoproterozoic was 3-10% shorter than today (Noyes et al 1984), whereas the Elatina Fm.…”

Section: Introductionmentioning

confidence: 99%

The End-Cryogenian Glaciation of South Australia

Rose

Maloof

Schoene

et al. 2013

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The Elatina Fm. records the younger Cryogenian ice age in the Adelaide Rift Complex (ARC) of South Australia, which has long-held the position as the type region for this low-latitude glaciation. Building upon a legacy of work, we document the pre- and syn-glacial sedimentary rocks to characterize the dynamics of the glaciation across the ARC. The Elatina Fm. records an array of well-preserved glacial facies at many different water depths across the basin, including ice contact tillites, fluvioglacial sandstones, dropstone intervals, tidal rhythmites with combined-flow ripples, and turbidites. The underlying Yaltipena Fm. records the pro-glacial influx of sediment from encroaching land-based ice sheets. The onset of the glaciation is heralded by the major element ratios (Chemical Index of Alteration) of the pre-glacial facies across the platform that show a reduction in chemical weathering and a deterioration in climate towards the base of the Elatina Fm. The advancing ice sheets caused soft-sediment deformation of the beds below the glacial diamictite, including sub-glacial push structures, as well as sub-glacial erosion of the carbonate unit beneath. Measured stratigraphic sections across the basin show glacial erosion up to 130 m into the carbonate platform. However, δ13C measurements of carbonate clasts within the glacial diamictite units were used to assess provenance and relative timing of δ13C acquisition, and suggest that at least 500 m of erosion occurred somewhere in the basin. Detrital zircon provenance data from the Elatina Fm. suggest that glacial sediment may have been partially sourced from the cratons of Western Australia and that the Whyalla Sandstone, even if stratigraphically correlative, was not a sediment source. The remainder of the Elatina Fm. stratigraphy mostly records the deglaciation and can be divided into three facies: a slumped sandstone, dropstone diamictite, and current-reworked diamictite. The relative sea level fall within the upper Elatina Fm. requires that regional deglaciation occurred on the timescale of ice sheet – ocean gravitational interactions (instant) and/or isostatic rebound (~104 years). Structures previously interpreted as soft-sediment folds within the rhythmite facies that were used to constrain the low-latitude position of South Australia at the time of the Elatina glaciation are re-interpreted as stoss-depositional transverse ripples with superimposed oscillatory wave ripples. These combined-flow ripples across the ARC attest to open seas with significant fetch during the initial retreat of local glaciers. In addition, this interpretation no longer requires that the magnetization be syn-depositional, although we have no reason to believe that the low-latitude direction is a result of remagnetization, and positive reversal tests and tectonic fold tests are at least consistent with syn-depositional magnetization. Together, these paired sedimentological and chemostratigraphic observations reveal the onset of the glaciation and advance of the ice sheet from land to create a heavily glaciated terrain that was incised down to at least the base of the pre-glacial Trezona Fm.SOMMAIRELa Formation d’Elatina représente la phase précoce de l’âge glaciaire du Cryogénien de l’Adelaide Rift Complex (ARC) dans le sud de l’Australie, région qui a longtemps été la région type de cette glaciation de basse latitude. À partir d’un legs de travaux, nous nous sommes appuyés sur l’étude des roches sédimentaires préglaciaires et synglaciaires pour caractériser la dynamique de la glaciation à travers l’ARC. La Formation d’Elatina renferme une gamme de faciès glaciaires bien préservés correspondant à différentes profondeurs d’eau à travers le bassin, dont des tillites de contact glaciaire, des grès fluvioglaciaires, des intervalles à galets de délestage, des rythmites tidales avec des combinaisons de rides d’écoulement, et des turbidites. La Formation sous-jacente de Yaltipena est constituée de sédiments proglaciaires provenant de lentilles de glace en progression. Le début de la glaciation est reflété dans les ratios des éléments majeurs (indice d’altération chimique) des faciès préglaciaires de la plateforme qui montre une réduction de l’altération chimique et une détérioration du climat à l’approche de la base de la Formation d’Elatina. La progression des nappes de glace a entraîné une déformation des lits de sédiments meubles sous la diamictite glaciaire, montrant entre autres des structures de poussée sous-glaciaires ainsi que de l’érosion sous-glaciaire de l’unité de carbonate sous-jacente. Les mesures de coupes stratigraphiques à travers le bassin montrent que l’érosion glaciaire a enlevé jusqu’à 130 m du carbonate de la plateforme. Toutefois, les signatures isotopiques δ13C de fragments de carbonate dans les unités de diamictites glaciaires utilisées pour établir la provenance et la chronologie d’acquisition relative de la signature δ13C des fragments, permet de penser qu’il y a eu au moins 500 m d'érosion quelque part dans le bassin. Les données de provenance sur zircons détritiques de la Formation d’Elatina permettent de penser que les sédiments glaciaires provenaient partiellement des cratons de l'Australie occidentale et que le grès de la Formation de Whyalla, bien que stratigraphiquement corrélé, n'a pas été une source de sédiments. Ce qui reste de la stratigraphie de la Formation d’Elatina représente principalement la déglaciation, laquelle peut être divisée en trois faciès : un grès plissé, une diamictite à galets de délestage, et une diamictite remaniée par des courants. La baisse du niveau relatif de la mer dans la partie supérieure de la Formation d’Elatina suppose une déglaciation régionale sur une échelle de temps de l’ordre de celle de la nappe de glace – interactions gravitationnelles de l’océan (instantanées) et/ou rebond isostatique (~ 104 ans). Des structures décrites précédemment comme des plis de sédiments mous dans des faciès de rhythmites qui impliquait une position de basse latitude pour l'Australie du Sud à l'époque de la glaciation Elatina, sont réinterprétées comme des rides sédimentaires transverses asymétriques avec des rides de vagues oscillatoires superposées. Ces combinaisons de rides d’écoulement à travers l’ARC confirment l’existence d’un milieu marin ouvert d’une ampleur certaine au moment de la retraite initiale des glaciers locaux. En outre, cette interprétation ne nécessite plus que la magnétisation soit synsédimentaire, bien que nous n'ayons aucune raison de penser que l’orientation magnétique de basse latitude soit le résultat d’une ré-aimantation, et que les tests de réversibilité positifs et les tests de plissement tectonique sont au minimum conformes à une magnétisation synsédimentaire. Ensemble, ces observations sédimentologiques et chimiostratigraphiques mettent en lumière le début de la glaciation et l'avancée du couvert de glace continental menant à une région fortement englacée qui a été incisée jusqu'à à la base de la Formation préglaciaire de Trezona.

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“…A -10-m-thick laminated unit at Pichi Richi Pass in the Fiinders Ranges is of interest both to astrophysics and paleoclimatology because of the complexity of periodic signals encoded by thickness variations of its delicate laminae (Williams, 1981(Williams, , 1985. Despite the apparent clarity of the signals, however, several interpretations of the cyclicity have now been proposed.…”

Section: Introductionmentioning

confidence: 99%

“…Despite the apparent clarity of the signals, however, several interpretations of the cyclicity have now been proposed. Based on the premise that the individual laminae represent yearly increments, Williams (1981Williams ( , 1985 and Williams and Sonett (1985) postulated that the Elatina periods are proxy for solar cyclicity. While accepting a yearly origin for the laminae, Zahnle and Walker (1987) argued that the Elatina periods reflect a combination of both solar and tidal cycles.…”

Section: Introductionmentioning

confidence: 99%

Cyclicity in the late Precambrian Elatina Formation, South Australia: Solar or tidal signature?

Williams

1988

Climatic Change

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New observations from two late Precambrian (-800-650 Ma) sedimentary rhythmites in South Australia (Reynella Siltstone and Chambers Bluff Tillite) reveal cycles structurally similar to the -12-1aminae cycles of the -650-Ma Elatina Formation but which comprise from 15 to 26 or more laminae. The new data are difficult to accomodate in depositional models for the Elatina Formation whereby its laminae are regarded as annual and the cyclicity ascribed to solar variability or to the combined influences of the sunspot cycle and the lunar nodal tide (Zahnle and Walker, 1987). If, however, the long-term 'Elatina Cycle' and not the individual lamina is taken as a yearly climatic signal, the Elatina and other rhythmites studied may be interpreted as the deposits of marine ebb-tidal deltas that record variability in the velocity and range of paleo-ebb tides. The basic laminae-cycles would represent lunar fortnightly cycles of diurnal and/or semidiurnal laminae, commonly truncated through non-deposition at neap tides. Despite numerous empirical similarities between the Elatina and sunspot series, the ebb-tidal model for deposition is preferred because it accounts plausibly for observations from all three rhythmites studied.

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Solar Affinity of Sedimentary Cycles in the Late Precambrian Elatina Formation

Cited by 37 publications

References 15 publications

Cicloestratigrafia Do Eopermiano - Estudo De Caso No Grupo Itararé, Bacia Do Paraná (Parte 2): Evidências De Indução Astronômica (Orbital E Solar) No Clima E Na Sedimentação

Cicloestratigrafia Do Eopermiano - Estudo De Caso No Grupo Itararé, Bacia Do Paraná (Parte 2): Evidências De Indução Astronômica (Orbital E Solar) No Clima E Na Sedimentação

The End-Cryogenian Glaciation of South Australia

Cyclicity in the late Precambrian Elatina Formation, South Australia: Solar or tidal signature?

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