Research Article| December 01, 2003 Fireball passes and nothing burns—The role of thermal radiation in the Cretaceous-Tertiary event: Evidence from the charcoal record of North America Claire M. Belcher; Claire M. Belcher 1 Department of Geology, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK Search for other works by this author on: GSW Google Scholar Margaret E. Collinson; Margaret E. Collinson 1 Department of Geology, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK Search for other works by this author on: GSW Google Scholar Arthur R. Sweet; Arthur R. Sweet 2Geological Survey of Canada, 3303 33rd Street NW, Calgary, Alberta T2L 2A7, Canada Search for other works by this author on: GSW Google Scholar Alan R. Hildebrand; Alan R. Hildebrand 3Department of Geology and Geophysics, University of Calgary, Alberta T2N 1N4, Canada Search for other works by this author on: GSW Google Scholar Andrew C. Scott Andrew C. Scott 1 Department of Geology, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK Search for other works by this author on: GSW Google Scholar Author and Article Information Claire M. Belcher 1 Department of Geology, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK Margaret E. Collinson 1 Department of Geology, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK Arthur R. Sweet 2Geological Survey of Canada, 3303 33rd Street NW, Calgary, Alberta T2L 2A7, Canada Alan R. Hildebrand 3Department of Geology and Geophysics, University of Calgary, Alberta T2N 1N4, Canada Andrew C. Scott 1 Department of Geology, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK Publisher: Geological Society of America Received: 01 Jul 2003 Revision Received: 25 Aug 2003 Accepted: 27 Aug 2003 First Online: 02 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2003) 31 (12): 1061–1064. https://doi.org/10.1130/G19989.1 Article history Received: 01 Jul 2003 Revision Received: 25 Aug 2003 Accepted: 27 Aug 2003 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Claire M. Belcher, Margaret E. Collinson, Arthur R. Sweet, Alan R. Hildebrand, Andrew C. Scott; Fireball passes and nothing burns—The role of thermal radiation in the Cretaceous-Tertiary event: Evidence from the charcoal record of North America. Geology 2003;; 31 (12): 1061–1064. doi: https://doi.org/10.1130/G19989.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract High soot contents have been reported in Cretaceous-Tertiary (K-T) sedimentary rocks, leading to the suggestion that the amount of thermal power delivered from the Chicxulub impact was sufficient to have ignited wildfires. Soot cannot be used to indicate fire location, however, as soot from one large fire could spread globally. Sources other than biomass burning could also yield soot. Charcoal in nonmarine sedimentary rocks (here quantified in situ in polished blocks) provides a unique tool to record the distribution of wildfires and therefore assess the extent of any thermal radiation associated with the impact at Chicxulub. The K-T and lowermost Tertiary sedimentary rocks of six nonma rine sequences (Colorado to Saskatchewan) contain no charcoal or below-background levels of charcoal and a significant quantity of noncharred organic materials, revealing that there was no distinctive wildfire across the North American continent related to the K-T event. This finding indicates that the K-T impact cannot have delivered a peak irradiance of >95 kW·m−2 of thermal power to the atmosphere and <19 kW·m−2 to the ground. Therefore, the thermal power delivered from the impact to North America did not have the destructive potential previously predicted. High amounts of thermal radiation were not responsible for the environmental perturbations or extinctions associated with the K-T event. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Sedimentology, organic petrology-geochemistry and palynology have been integrated to study fine-grained, siliciclastic Eocene sediments deposited within a small kimberlite crater basin, Lac de Gras, Northwest Territories, Canada.The strata represent a shallowing-upward succession of lake basin-fill including three stratal units: a lower unit of dark organic-rich mudstone (% total organic carbon: TOC = 15-50 %) interpreted as low energy, shallow sub-lacustrine deposition; a thin transitional unit with evidence of near surface exposure (TOC = 2-12 %); and an upper unit characterized by thick peat bog deposits (TOC = 39-55 %).Both upper and lower portions of the sediments are characterized by shallowing-upward, higher order sequences suggesting cyclic climatic wet/dry phases.Their boundaries correspond with marked changes in TOC, and Rock-Eval hydrogen and oxygen indices.The combined presence of Pistillipollenites mcgregorii, and forms of Platycarya restricts the age of the Giraffe sediments to late early to early middle Eocene.These taxa do not occur in the upper part of the core which may only reflect a shift in depositional environment.The distribution and type of microscopic organic matter reflects the sedimentological observations with the lower, lacustrine zone consisting of abundant diatoms, chrysophytes and liptinites (e.g.sporinite, alginite), and the upper, peat bog zone consisting predominantly of woody macerals.Huminites through the section have reflectance values averaging 0.23 %Ro, indicating that thermal maturity is slightly greater than modern peats and that post-kimberlite burial and thermal alteration have been insignificant with temperatures no greater than ~ 30 ° C.
Research Article| May 01, 1997 Thrust-top basin formation along a suture zone, Cantwell basin, Alaska Range: Implications for development of the Denali fault system Kenneth D. Ridgway; Kenneth D. Ridgway 1Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907-1397 Search for other works by this author on: GSW Google Scholar Jeffrey M. Trop; Jeffrey M. Trop 1Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907-1397 Search for other works by this author on: GSW Google Scholar Arthur R. Sweet Arthur R. Sweet 2Geological Survey of Canada, Calgary, Alberta T2L 2A7, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Kenneth D. Ridgway 1Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907-1397 Jeffrey M. Trop 1Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907-1397 Arthur R. Sweet 2Geological Survey of Canada, Calgary, Alberta T2L 2A7, Canada Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1997) 109 (5): 505–523. https://doi.org/10.1130/0016-7606(1997)109<0505:TTBFAA>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Kenneth D. Ridgway, Jeffrey M. Trop, Arthur R. Sweet; Thrust-top basin formation along a suture zone, Cantwell basin, Alaska Range: Implications for development of the Denali fault system. GSA Bulletin 1997;; 109 (5): 505–523. doi: https://doi.org/10.1130/0016-7606(1997)109<0505:TTBFAA>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Cantwell Formation consists of a lower sedimentary sequence as much as 4000 m thick and an upper volcanic sequence with a maximum thickness of 3750 m that was deposited in the Cantwell basin, south-central Alaska. Previous to this study, the Cantwell basin was interpreted as a Paleogene, nonmarine (mainly fluvial), pull-apart basin that formed in response to dextral, strike-slip displacement on the Denali fault system. This study proposes that the Cantwell basin formed as part of the Mesozoic accretionary phase of deformation, prior to the development of the Cenozoic postaccretionary Denali fault system. Our reinterpretation is based on several new lines of data.(1) Age. New data based on palynologic analyses of 135 fine-grained samples indicate that the lower Cantwell Formation was deposited during the late Campanian and early Maastrichtian. On the basis of previous regional tectonic studies and this new age constraint, the formation of the Cantwell basin was coeval with regional Late Cretaceous shortening associated with accretionary tectonics in southern Alaska.(2) Depositional systems. Our analysis of the Cantwell Formation demonstrates that sedimentation occurred mainly in stream-dominated alluvial fan, axial braided stream, and lacustrine settings. These depositional systems were strongly influenced by a southward dipping, asymmetric basin floor. The presence of abundant terrestrially derived organic material, together with palynological assemblages that include marine dinoflagellates and the associated presence of oncolites, may be suggestive of a time of marginal marine influence during the deposition of the upper part of the lower Cantwell Formation. The late Campanian to early Maastrichtian timing of this possible marine influence is within the range of the Bearpaw transgressive event of the Cordilleran foreland basin and allows for regional stratigraphic correlation of the Cantwell basin with other sedimentary basins in northwestern North America.(3) Structural controls on basin formation. Mapping of intraformational angular unconformities and progressively tilted strata along the southern margin of the Cantwell basin provides direct evidence that thrust fault deformation and lower Cantwell Formation sedimentation were synchronous. Distinctive Cantwell Formation conglomerate clasts derived from the uplifted hanging walls of nearby thrust sheets adjacent to the southern basin margin also support a syndepositional thrusting interpretation. Provenance data and the concentration of proximal alluvial fan deposits along the northwestern basin margin adjacent to the Hines Creek fault indicate that it, too, was active during deposition of the Cantwell Formation.On the basis of the new data, the Cantwell basin is interpreted to have formed as a thrust-top basin (i.e., piggyback basin) along the Late Cretaceous suture zone between the accreting Wrangellia composite terrane and the North American continental margin. In contrast to previous studies, this reinterpretation of the formation of the Cantwell basin implies that the lower Cantwell Formation is not a synorogenic deposit directly associated with strike-slip displacement along the Denali fault system. Therefore, the Cantwell basin cannot be used to constrain the timing for the early development of the Denali fault system. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Although mammals of Paleocene age are well known from Alberta, their record is largely restricted to one lithological unit, the Paskapoo Formation (a record that includes mammals from the Cochrane area erroneously attributed to the Porcupine Hills Formation). We report here the first occurrence of Paleocene mammals from the Porcupine Hills Formation at exposures near the western edge of the city of Calgary. The assemblage, termed the Bearspaw local fauna, documents a diversity of multituberculate and eutherian mammals, including new species of the pentacodontid Aphronorus bearspawensis sp. nov., the mixodectid Eudaemonema bohachae sp. nov., the hyopsodontid Promioclaenus thnetus sp. nov., and a new genus and species of multituberculate (Alopocosmodon hadrus gen. et sp. nov.) tentatively referred to the Microcosmodontidae. The Bearspaw local fauna also details the first Canadian occurrences of several taxa, including Ptilodus wyomingensis, Aphronorus fraudator, Bryanictis microlestes, Elpidophorus minor, and possibly Goniacodon. Preliminary biostratigraphic analyses suggest that the Bearspaw local fauna is middle Torrejonian (To2) in age, correlating most closely with near-coeval Gidley Quarry of Montana and Rock Bench Quarry of Wyoming. In addition to improving the depauperate record of Torrejonian mammals in western Canada, the new fauna is important in documenting a mammal assemblage from a lithological unit that is thought to have been deposited in semi-arid conditions, rather than the wetter and more humid conditions of the Paskapoo Formation. Further, the Bearspaw localities, along with several other recently discovered localities in the Calgary and Cochrane areas, closely bracket the 27n–26r chron boundary and as such will be important in detailing the Torrejonian–Tiffanian transition in western Canada.
Pandemonium hibernalis sp. nov., from a middle? Puercan (earliest Paleocene) locality in the upper Scollard Formation, Wintering Hills, southern Alberta, represents the second discovered occurrence of the enigmatic plesiadapiform primate Pandemonium Van Valen and the first from Canada. The holotype of Pandemonium hibernalis is the only known specimen of Pandemonium documented by multiple teeth from a single individual. Pandemonium hibernalis closely resembles the type species Pandemonium dis from Purgatory Hill, middle–late Puercan, Tullock Formation, Montana, but differs in having wider, more bunodont lower molar crowns and a more expanded posterior talonid lobe of m3, specializations suggesting enhanced capacity for crushing and grinding of soft food materials during mastication. Pandemonium hibernalis joins other recent discoveries in Alberta and elsewhere in the North American Western Interior in documenting a moderate radiation of basal plesiadapiforms that evolved unexpectedly early during primate evolution.
Introduction Nichols and Sweet (1993) published the first comprehensive review of a pollen and sporebased Late Cretaceous biostratigraphy for midcontinental North America, including western and northern Canada. The ultimate goals of this and subsequent Albian to Paleogene palynological studies have been to gain an enhanced understanding of biochronologies, paleoclimates and the timing of tectonic and eustatic events. Over the past 30 years data has been accumulated from the Alberta Foreland, Nechako, Sustut, Bonnet Plume and Brackett basins. Of these, three basins are dominantly non-marine; Nechako and Sustut of central and north-central British Columbia, respectively and the Bonnet Plume of eastcentral Yukon Territories. Central and southern Alberta, and the Brackett Basin of the Northwest Territories have interfingering marine and non-marine strata and the Smoky River/Clear Hills and Buffalo Head Hills areas, in north-central Alberta, are dominantly marine. In this presentation the focus will be on northcentral Alberta sections and the Bonnet Plume and Nechako basins. Studies in these areas have supported kimberlite, stratigraphic, sedimentological and mapping activities. Inevitably these applied studies have contributed to increasing the reliability of other palynological applications.
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