Palaeoenvironmental and sedimentological context for dinosaurian assemblages in the Mussentuchit Member, Cedar Mountain Formation, central Utah (USA)
| dc.contributor.advisor | Tucker, Ryan T. | en_ZA |
| dc.contributor.advisor | Zanno, Lindsay Elizabeth | en_ZA |
| dc.contributor.author | Jonk, Louis | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Science. Dept. of Earth Sciences. | en_ZA |
| dc.date.accessioned | 2018-10-15T12:55:09Z | |
| dc.date.accessioned | 2018-12-10T06:34:29Z | |
| dc.date.available | 2018-10-15T12:55:09Z | |
| dc.date.available | 2018-12-10T06:34:29Z | |
| dc.date.issued | 2018-12 | |
| dc.description | Thesis (MSc)--Stellenbosch University, 2018. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: The Cretaceous-aged sediments of the Western North America Interior preserve the geological and biological signatures of notable tectonic events in Earth’s history, such as the formation of the Western Interior Basin and Beringian Land Bridge. The Mussentuchit Member of the Cedar Mountain Formation is a fossiliferous sedimentary succession that preserves a key portion of the geological and biological evolution of the North American Western Interior Basin. The geological and temporal context for this unit, however, remains limited. This study, therefore, attempts to place recently opened fossil quarries within the Mussentuchit Member near Cathedral Valley, Utah into a rigorous geological framework via stratigraphic, palaeoenvironmental, and temporal analysis. This study identified fifteen facies and seven architectural elements, which were combined into six representative facies associations. Further, this study concludes that these sediments were deposited within a fluctuating, distal deltaic, or tidal mudflat. Stratigraphic reconstructions place the Mussentuchit Member near Cathedral Valley, Utah as the uppermost member of the Cedar Mountain Formation, with notable variations in sedimentation patterns between the lower and upper Mussentuchit. The change in sedimentation illustrates the gradation from a, supra-tidal zone (lower Mussentuchit), to inter tidal to sub-tidal zone (upper Mussentuchit) of the tidal delta. Geochronological results from radiometric dating of detrital zircon assemblages indicate that these environments developed in response to multiple tectonic events. Specifically, these include thin-skinned thrusting, subsequent internal breakup, and duplexing of the Pavant Sheet of the Sevier Orogeny. These tectonic events are respectively estimated to have occurred during the Albian (±110.92 Ma), Cenomanian (±96.00 Ma) and Turonian (±93.00 Ma), with actual sedimentation of the member estimated to have occurred from the Cenomanian (±98.00 Ma) to Turonian (±93.00 Ma). This change in thrusting mechanisms resulted in the respective deposition of the lower Mussentuchit and upper Mussentuchit within the late-underfilled stage and filled to overfilled stage of the Sevier Foredeep; the depositional low within the Western Interior basin closest to the orogenic highlands. Results from this study added geological context to the fossil quarries on the western flank of the San Rafael Swell, near Cathedral Valley, Utah. Sediments from the lower Mussentuchit and quarries preserved there were dated at a maximum age of deposition of ±105.00 Ma (Albian), though a younger depositional age of ±98.00 Ma is suspected. The Fortunate Son fossil quarry, positioned within the lower Mussentuchit, was placed within the supra-tidal portion of a tidal delta. Detrital zircons from the Mini Troll and Suicide Hill fossil quarries of the upper Mussentuchit were radiometrically dated at a Cenomanian age of ±93.95 Ma and ±93.45 Ma, respectively, and placed within the intertidal to intertidal-subtidal transition zone of a tidal delta. This study provides a more robust understanding of the Mussentuchit sedimentation and enables more meaningful comparisons with regional-scale geological and faunal evolution. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Sedimentêre gesteentes in Innerlike Wes-Noord Amerika van die Kryt-tydperk preserveer die geologiese en biologiese tekens van belangrike tektoniese gebeurtenisse in die Aarde se geskiedenis, soos die formasie van die Westerlike Interne Kom en die Beringian Land Brug. Die Mussentuchit Lid van die Cedarberg Formasie is ’n fossielryke sedimentêre gesteente wat kerngedeeltes van die geologiese en biologiese evolusie van die Noord Amerikaanse Westerlike Interne Kom preserveer. Tog is die geologiese en temporale konteks vir hierdie eenheid beperk. Hierdie studie poog dus om onlangs ontblote fossielsteengroewe in die Mussentuchit Lid naby Cathedral Valley, Utah in ’n samevattende raamwerk deur middel van stratigrafiese-, paleo-omgewings-, en temporale analise te beskryf. Hierdie studie het vyftien fasies en sewe argitektoniese elemente identifiseer, wat kombineer was in ses verteenwoordige fasies assosiasies. Verder het die studie getoon dat hierdie sedimente deponeer was in ’n wisselende, distale deltaïese of getyvlakte. Stratigrafiese herbouings plaas die Mussentuchit Lid naby Cathedral Valley, Utah, as die heel boonste lid van die Cedarberg Formasie, met opmerklike verskille in sedimentasiepatrone tussen die onderste en boonste Mussentuchit. Die verandering in sedimentasiepatrone illustreer die geleidelike verandering vanaf ’n fluviaal-gedomineerde, supra-gety sone (laer Mussentuchit) tot die gety-gedomineerde inter-gety tot sub-gety sone (hoër Mussentuchit) van die gety delta. Geochronologiese resultate van radiometriese datering van detrale sirkone toon dat hierdie omgewings ontwikkel het in respons tot verskeie tektoniese gebeurtenisse. Hierdie sluit in dunvellige stoting, gevolglike interne opbreek, en tyddeling van die Pavant Plaat van die Sevier Orogenie. Hierdie tektoniese gebeurtenisse word onderskeidelik beraam om plaas te gevind het gedurende die Albian (±110.92 Ma), Cenomanian (±96.00 Ma) en Tortonien (±93.00 Ma), met werklike sedimentasie van die lid beraam om plaas te gevind het vanaf die Cenomanian (±98.00 Ma) tot die Tortonien (±93.00 Ma). Hierdie verandering in stotingsmeganismes het gelei tot die onderskeidelike deposisie van die laer Mussentuchit en die hoër Mussentuchit binne die laat-ondergevulde stadium en gevulde tot oorgevulde stadium van die Sevier Voorland Trog; ʼn strukturele element wat ’n deposisionele vermindering verteenwoordig in die Westerlike Interne Kom. Resultate van hierdie studie het geologiese konteks bygedra tot die fossielgroewe op die westerlike flank van die San Rafael Swell, naby Cathedral Valley, Utah. Sedimente van die laer Mussentuchit en die steengroewe daarin is dateer teen 'n maksimum ouderdom van ± 105.00 Ma (Albian), alhoewel 'n jonger afsettingsouderdom van ± 98.00 Ma vermoed word. Die Fortunate Son-fossielgroef, geleë in die laer Mussentuchit, is in die opper-gety porsie van 'n gety-delta geplaas. Detrale sirkone van die Mini Troll en Suicide Hill fossielgroewe van die hoër Mussentuchit is onderskeidelik radiometries dateer op 'n Cenomaniaanse ouderdom van ± 93.95 Ma en ± 93.45 Ma, en is geplaas in die tussengety tyd tot subgety oorgangssone van 'n gety-delta. Hierdie studie bied 'n meer robuuste begrip van die Mussentuchit sedimentasieprosesse en stel navorsers in staat om meer betekenisvolle vergelykings te maak met die streeksskaalse geologiese en faunale evolusie. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.embargo.terms | 2020-12-31 | |
| dc.format.extent | xii, 149 pages : illustrations (some color) | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/105144 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Geology, Stratigraphic -- Cretaceous -- Cedar Mountain Formation -- Utah | en_ZA |
| dc.subject | Mussentuchit Member | en_ZA |
| dc.subject | Facies (Geology) -- San Rafael Swell | en_ZA |
| dc.subject | Geochronology | en_ZA |
| dc.subject | Western Interior Seaway | en_ZA |
| dc.subject | Sevier Foreland Basin | en_ZA |
| dc.subject | Cordilleran Fold Belt | en_ZA |
| dc.subject | Palaeoenvironmental reconstruction | en_ZA |
| dc.subject | Sediments (Geology) -- Analysis -- Utah -- Cedar Mountain Formation | en_ZA |
| dc.title | Palaeoenvironmental and sedimentological context for dinosaurian assemblages in the Mussentuchit Member, Cedar Mountain Formation, central Utah (USA) | en_ZA |
| dc.type | Thesis | en_ZA |
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