Jura-Cretaceous (Oxfordian to Cenomanian) stratigraphy of the north-central Bowser Basin, northern British Columbia

1989 ◽  
Vol 26 (5) ◽  
pp. 1001-1012 ◽  
Author(s):  
H. O. Cookenboo ◽  
R. M. Bustin
Keyword(s):  
British Columbia ◽  
Lower Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Upper Jurassic ◽  
Thick Section ◽  
North Central ◽  
The North

Three new formations of Late Jurassic and Early to mid-Cretaceous age are defined for a 2000 m thick section of Jura-Cretaceous rocks exposed in the north-central Bowser Basin. The Currier Formation (Oxfordian to Kimmeridgian or Tithonian) consists of 350–600 m of interbedded shales, siltstones, sandstones, coals, and carbonates. The McEvoy Formation (Barremian to as young as Albian) consists of 400–800 m of siltstones and shales with minor sandstones, thin coals, limestones, and conglomerates. The Devils Claw Formation (in part mid-Albian to Cenomanian) consists of 300–600 m of strata characterized by thick pebble and cobble conglomerates, with associated coarse sandstones and minor siltstones and shales.Two successive coarsening-upward sequences are identified in the study area. The first begins with Middle Jurassic marine shales of the Jackson unit grading upwards to coarser Upper Jurassic facies of the Currier Formation. The Currier Formation is conformably or unconformably overlain by siltstones and shales of the Lower Cretaceous McEvoy Formation, which forms the base of a second coarsening-upward sequence. Conglomerates appear with increasing frequency in the upper McEvoy and are the dominant lithology of the overlying Devils Claw Formation. The contact between the McEvoy and Devils Claw formations is gradational. The Devils Claw Formation forms the top of the second coarsening-upward sequence.The Currier Formation (Late Jurassic) is equivalent to the upper units of the Bowser Lake Group. The McEvoy and the Devils Claw formations (Barremian to Cenomanian) are coeval with the Skeena Group (Hauterivian? to Cenomanian). A probable unconformity separating the Upper Jurassic Currier Formation from the Lower Cretaceous McEvoy Formation correlates with a hiatus in the southern Bowser Basin and probably represents a regional unconformity.

Lower to Middle Jurassic (Pliensbachian to Bajocian) stratigraphy of the northern Spatsizi area, north-central British Columbia

1986 ◽  
Vol 23 (12) ◽  
pp. 1963-1973 ◽  
Author(s):  
Robert C. Thomson ◽  
Paul L. Smith ◽  
Howard W. Tipper
Keyword(s):  
British Columbia ◽  
Grain Size ◽  
Middle Jurassic ◽  
Water Environment ◽  
Upper Jurassic ◽  
Calc Alkaline ◽  
Volcanic Arc ◽  
North Central ◽  
Area North ◽  
Southern Flank

The Lower to Middle Jurassic (Pliensbachian to lower Bajocian) Spatsizi Group in the northern Spatsizi area of north-central British Columbia is formally defined and subdivided into the Joan, Wolf Den, Melisson, Abou, and Quock formations. Each formation reflects deposition in a different, dominantly fine-clastic environment with a varying input of volcanic (epiclastic or pyroclastic) detritus. The Spatsizi Group represents the basinward sedimentary equivalent of the coeval Cold Fish Volcanics, a group of calc-alkaline flows and breccias that accumulated in a volcanic arc along the southern flank of the Stikine Arch. Arc-to basin-facies trends are best developed in the Joan and Wolf Den formations and are characterized by a decrease in the volcaniclastic component of the sediments, an overall reduction in grain size, and a progressively deeper water environment of deposition, as inferred from both sedimentological and faunal evidence.In the study area, the Spatsizi Group underlies with a slight angular discordance the Middle to Upper Jurassic Bowser Lake Group. Bowser lake sediments were deposited in the Bowser Basin, the largest Mesozoic successor basin in British Columbia. Based on evidence from the Spatsizi area and from other areas to the south at Diagonal Mountain and the Oweegee Mountains, the Spatsizi Group is interpreted as passing laterally into shales that underlie most of the Bowser Basin.

Geochronology and tectonics of the northern Wolverine Complex, British Columbia

1979 ◽  
Vol 16 (7) ◽  
pp. 1428-1438 ◽  
Author(s):  
Randall R. Parrish
Keyword(s):  
British Columbia ◽  
Late Jurassic ◽  
Blocking Temperature ◽  
Mountain Area ◽  
North Central ◽  
Geothermal Gradients ◽  
Clastic Rocks ◽  
The North ◽  
Uplift Rates ◽  
Uplift And Erosion

The Wolverine Complex is a metamorphosed and polydeformed sequence of Hadrynian clastic rocks that forms part of the Omineca Crystalline Belt in north-central British Columbia. Twenty-six Rb–Sr and K–Ar dates from an area at the north end of the complex are presented. Rb–Sr muscovite dates are the oldest, 70–166 Ma, and constrain the main metamorphic–deformational event to the Middle to Late Jurassic or earlier. K–Ar dates on muscovite and biotite are highly discordant and the dates of the minerals vary in the order Rb–Sr muscovite > K–Ar muscovite > K–Ar biotite. Many rocks show partial or complete homogenization of the isotopes during an early Tertiary thermal event, which has extensively reset K–Ar dates in part of the complex.The blocking temperatures of the isotopic systems when combined with the isotopic dates, other published dates, and estimated geothermal gradients, allow inference of thermal history and paleo-uplift rates. In the Chase Mountain area where the influence of Eocene resetting is either small or minimal, the rocks had cooled to 220 ± 40 °C by about 80 Ma ago or earlier. During their cooling from metamorphic temperatures of about 500 °C, they cooled at rates between 3 and 10 °C/Ma with an average minimum cooling rate of 4 °C/Ma. Using estimated geothermal gradients, corresponding uplift rates were 0.1–0.3 km/Ma or more.Because cooling of these rocks probably took place dominantly by advection resulting from uplift and erosion, a significant portion of the total uplift of these rocks was complete by the time they reached the biotite blocking temperature, 220 °C, at least 80 Ma ago. The predominantly Late Jurassic to Early Cretaceous uplift of the complex implied by these dates has important implications for regional tectonics and models of evolution for the Omineca Crystalline Belt and adjacent areas.

scholarly journals Upper Jurassic – Lower Cretaceous of the Danish Central Graben: structural framework and nomenclature

2003 ◽  
Vol 1 ◽  
pp. 231-246 ◽  
Author(s):  
Peter Japsen ◽  
Peter Britze ◽  
Claus Andersen
Keyword(s):  
North Sea ◽  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Late Jurassic ◽  
Upper Jurassic ◽  
The South ◽  
Structural Element ◽  
Maximum Thickness ◽  
The North ◽  
Half Graben

The Danish Central Graben is part of the mainly Late Jurassic complex of grabens in the central and southern North Sea which form the Central Graben. The tectonic elements of the Danish Central Graben in the Late Jurassic are outlined and compared to those in the Early Cretaceous based on reduced versions of published maps (1:200 000), compiled on the basis of all 1994 public domain seismic and well data. The Tail End Graben, a half-graben which stretches for about 90 km along the East North Sea High, is the dominant Late Jurassic structural feature. The Rosa Basin (new name) is a narrow, north–south-trending basin extending from the south-western part of the Tail End Graben. The Tail End Graben ceased to exist as a coherent structural element during the Early Cretaceous and developed into three separate depocentres: the Iris and Gulnare Basins to the north and the Roar Basin to the south (new names). The Early Cretaceous saw a shift from subsidence focused along the East North Sea High during the Late Jurassic to a more even distribution of minor basins within the Danish Central Graben. The depth to the top of the Upper Jurassic – lowermost Cretaceous Farsund Formation reaches a maximum of 4800 m in the northern part of the study area, while the depth to the base of the Upper Jurassic reaches 7500 m in the Tail End Graben, where the Upper Jurassic attains a maximum thickness of 3600 m. The Lower Cretaceous Cromer Knoll Group attains a maximum thickness of 1100 m in the Outer Rough Basin.

New multituberculate mammal from the Early Cretaceous of eastern North America

2013 ◽  
Vol 50 (3) ◽  
pp. 315-323 ◽  
Author(s):  
Richard L. Cifelli ◽  
Cynthia L. Gordon ◽  
Thomas R. Lipka
Keyword(s):  
North America ◽  
Iberian Peninsula ◽  
Early Cretaceous ◽  
North American ◽  
Lower Cretaceous ◽  
Late Jurassic ◽  
Relative Length ◽  
Central Position ◽  
Eastern North America ◽  
The North

Multituberculates, though among the most commonly encountered mammalian fossils of the Mesozoic, are poorly known from the North American Early Cretaceous, with only one taxon named to date. Herein we describe Argillomys marylandensis, gen. et sp. nov., from the Early Cretaceous of Maryland, based on an isolated M2. Argillomys represents the second mammal known from the Arundel Clay facies of the Patuxent Formation (Lower Cretaceous: Aptian). Though distinctive in its combination of characters (e.g., enamel ornamentation consisting of ribs and grooves only, cusp formula 2:4, presence of distinct cusp on anterobuccal ridge, enlargement of second cusp on buccal row, central position of ultimate cusp in lingual row, great relative length), the broader affinities of Argillomys cannot be established because of non-representation of the antemolar dentition. Based on lack of apomorphies commonly seen among Cimolodonta (e.g., three or more cusps present in buccal row, fusion of cusps in lingual row, cusps strongly pyramidal and separated by narrow grooves), we provisionally regard Argillomys as a multituberculate of “plagiaulacidan” grade. Intriguingly, it is comparable in certain respects to some unnamed Paulchoffatiidae, a family otherwise known from the Late Jurassic – Early Cretaceous of the Iberian Peninsula.

scholarly journals The Upper Jurassic Morrison Formation in north-central New Mexico–Linking Colorado Plateau stratigraphy to the stratigraphy of the High Plains

2018 ◽  
Vol 5 ◽  
pp. 117-129 ◽  
Author(s):  
Spencer Lucas
Keyword(s):  
New Mexico ◽  
Colorado Plateau ◽  
Far East ◽  
River System ◽  
Upper Jurassic ◽  
High Plains ◽  
Morrison Formation ◽  
Southern High Plains ◽  
North Central ◽  
The North

Most study of the Upper Jurassic Morrison Formation has focused on its spectacular and extensive outcrops on the southern Colorado Plateau. Nevertheless, outcrops of the Morrison Formation extend far off the Colorado Plateau, onto the southern High Plains as far east as western Oklahoma. Outcrops of the Morrison Formation east of and along the eastern flank of the Rio Grande rift in north-central New Mexico (Sandoval, Bernalillo, and San­ta Fe Counties) are geographically intermediate between the Morrison Formation outcrops on the southeastern Colorado Plateau in northwestern New Mexico and on the southern High Plains of eastern New Mexico. Previous lithostratigraphic correlations between the Colorado Plateau and High Plains Morrison Formation outcrops using the north-central New Mexico sections encompassed a geographic gap in outcrop data of about 100 km. New data on previously unstudied Morrison Formation outcrops at Placitas in Sandoval County and south of Lamy in Santa Fe County reduce that gap and significantly add to stratigraphic coverage. At Placitas, the Morrison Formation is about 141 m thick, in the Lamy area it is about 232 m thick, and, at both locations, it consists of the (ascending) sandstone-dominated Salt Wash Member, mudstone-dominated Brushy Basin Member, and sandstone-dominat­ed Jackpile Member. Correlation of Morrison strata across northern New Mexico documents the continuity of the Morrison depositional systems from the Colorado Plateau eastward onto the southern High Plains. Along this transect, there is significant stratigraphic relief on the base of the Salt Wash Member (J-5 unconformity), the base of the Jackpile Member, and the base of the Cretaceous strata that overlie the Morrison Formation (K unconfor­mity). Salt Wash Member deposition was generally by easterly-flowing rivers, and this river system continued well east of the Colorado Plateau. The continuity of the Brushy Basin Member, and its characteristic zeolite-rich clay facies, onto the High Plains suggests that localized depositional models (e.g., “Lake T’oo’dichi’) need to be re-eval­uated. Instead, envisioning Brushy Basin Member deposition on a vast muddy floodplain, with some localized lacustrine and palustrine depocenters, better interprets its distribution and facies.

scholarly journals Decomposition of dinosaurian remains inferred by invertebrate traces on vertebrate bone reveal new insights into Late Jurassic ecology, decay, and climate in western Colorado

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9510
Author(s):  
Julia B. McHugh ◽  
Stephanie K. Drumheller ◽  
Anja Riedel ◽  
Miriam Kane
Keyword(s):  
Late Jurassic ◽  
Upper Jurassic ◽  
Site Formation ◽  
Morrison Formation ◽  
Bone Surface ◽  
The North ◽  
Western Colorado ◽  
Burial Rates ◽  
Minimum Residence Time ◽  
Taphonomic Analysis

A survey of 2,368 vertebrate fossils from the Upper Jurassic Mygatt-Moore Quarry (MMQ) (Morrison Formation, Brushy Basin Member) in western Colorado revealed 2,161 bone surface modifications on 884 specimens. This is the largest, site-wide bone surface modification survey of any Jurassic locality. Traces made by invertebrate actors were common in the assemblage, second in observed frequency after vertebrate bite marks. Invertebrate traces are found on 16.174% of the total surveyed material and comprise 20.148% of all identified traces. Six distinct invertebrate trace types were identified, including pits and furrows, rosettes, two types of bioglyph scrapes, bore holes and chambers. A minimum of four trace makers are indicated by the types, sizes and morphologies of the traces. Potential trace makers are inferred to be dermestid or clerid beetles, gastropods, an unknown necrophagous insect, and an unknown osteophagus insect. Of these, only gastropods are preserved at the site as body fossils. The remaining potential trace makers are part of the hidden paleodiversity from the North American Late Jurassic Period, revealed only through this ichnologic and taphonomic analysis. Site taphonomy suggests variable, but generally slow burial rates that range from months up to 6 years, while invertebrate traces on exposed elements indicate a minimum residence time of five months for carcasses with even few preserved invertebrate traces. These traces provide insight into the paleoecology, paleoclimate, and site formation of the MMQ, especially with regards to residence times of the skeletal remains on the paleolandscape. Comprehensive taphonomic studies, like this survey, are useful in exploring patterns of paleoecology and site formation, but they are also rare in Mesozoic assemblages. Additional work is required to determine if 16.174% is typical of bulk-collected fossils from Jurassic ecosystems in North America, or if the MMQ represents an unusual locality.

Late Palaeozoic to Early Cenozoic geological evolution of the northwestern German North Sea (Entenschnabel): New results and insights

2014 ◽  
Vol 93 (4) ◽  
pp. 147-174 ◽  
Author(s):  
Jashar Arfai ◽  
Fabian Jähne ◽  
Rüdiger Lutz ◽  
Dieter Franke ◽  
Christoph Gaedicke ◽  
...  
Keyword(s):  
North Sea ◽  
Lower Cretaceous ◽  
Late Jurassic ◽  
Structural Element ◽  
The North ◽  
Sedimentary Evolution ◽  
Basin Subsidence ◽  
The North Sea ◽  
Thickness Variations ◽  
Zechstein Salt

AbstractThe results of a detailed seismic mapping campaign of 13 horizons in the northwestern German North Sea, covering Late Permian to Palaeogene sedimentary successions, are presented. Based on the interpretation of four 3D and two 2D seismic surveys, thickness and depth maps of prominent stratigraphic units were constructed. These maps provide an overview of key structural elements, the sedimentation and erosion, and give insights into the evolution of the German Central Graben. The base of the Zechstein Group reaches a maximum depth of 7800 m within the German Central Graben. Lateral thickness variations in the Zechstein reflect the extensive mobilisation of Zechstein salt. Complex rift-related structures, with the Central Graben as the main structural element, were found not later than the Early Triassic. Up to 3000-m thick Triassic sediments are preserved in the eastern German Central Graben of which 1800 m consist of Keuper sediments. The Lower Buntsandstein unit shows increasing thicknesses towards the southeastern study area, likely related to distinct lateral subsidence. As a consequence of uplift of the North Sea Dome, Middle Jurassic sediments were eroded in large parts of the northwestern German North Sea and are only preserved in the German Central Graben. The NNW–SSE oriented John Basin is another important structural element, which shows maximum subsidence during the Late Jurassic. In most parts of the study area Lower Cretaceous sediments are absent due to either erosion or non-deposition. Lower Cretaceous deposits are preserved in the Outer Rough Basin in the northwest and within the German Central Graben. Upper Cretaceous sediments are found at depths between 1500 and 3600 m, reaching a maximum thickness of approximately 1600 m on the Schillgrund High. Contraction and inversion of pre-existing Mesozoic faults during the Late Cretaceous is distinct at the Schillgrund Fault, i.e. the eastern border fault of the Central Graben. The Palaeogene is predominantly a period of strong basin subsidence. Within 37 Myrs, up to 1400 m of Palaeogene sediments were deposited in the northwesternmost part of the study area. Detailed mapping of salt structures enables a reconstruction of halokinetic movements over time and a deciphering of the influence of the Zechstein salt on the sedimentary evolution during the Mesozoic and Cenozoic. Increasing sediment thicknesses in rim-synclines indicate that most of the salt structures in the German Central Graben had their main growth phase during the Late Jurassic.

Glendonites from Mesozoic succession of eastern Barents sea: distribution, genesis and paleoclimatic implications

2020 ◽  
Author(s):  
Kseniya Mikhailova ◽  
Victoria Ershova ◽  
Mikhail Rogov ◽  
Boris Pokrovsky ◽  
Oleg Vereshchagin
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Sulfate Reduction ◽  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Middle Jurassic ◽  
Barents Sea ◽  
Upper Jurassic ◽  
Anaerobic Oxidation Of Methane ◽  
Oxidation Of Methane

<p>Glendonites often used as paleoclimate indicator of cold near-bottom temperature, as these are calcite pseudomorphs of ikaite, a metastable calcium carbonate hexahydrate, precipitates mostly under low temperature (mainly from 0-4<sup>o</sup>C) and may be stabilized by high phosphate concentrations that occurs due to anaerobic oxidation of methane and/or organic matter; dissolved organic carbon, sulfates and amino acid may contribute ikaite formation as well.  Therefore, glendonites-bearing host rocks frequently include glacial deposits that make them useful as a paleoclimate indicator of near-freezing temperature.</p><p>Our study is based on material collected from five wells drilled in eastern Barents Sea: Severo-Murmanskaya, Ledovaya – 1,2; Ludlovskaya – 1,2. The studied glendonites, mainly represented by relatively small rhombohedral pseudomorphs (0,5-2 cm) and rarely by stellate aggregates, collected from Middle Jurassic to Lower Cretaceous shallow marine clastic deposits. They scattered distributed throughout succession. Totally 18 samples of glendonites were studied. The age of host-bearing rocks were defined by fossils: bivalves or ammonites, microfossils or dinoflagellate. Bajocian-Bathonian glendonites were collected from Ledovaya – 1 and Ludlovskaya – 1 and 2 wells; in addition to these occurrences Middle Jurassic glendonites are known also in boreholes drilled at Shtockmanovskoe field. Numerous ‘jarrowite-like’ glendonites of the Middle Volgian (~ latest early Tithonian) age were sampled from Severo-Murmanskaya well. Unique Late Barremian glendonites were found in Ledovaya – 2 well.</p><p>δ<sup>18</sup>O values of Middle Jurassic glendonite concretions range from – 5.4 to –1.7 ‰ Vienna Pee Dee Belemnite (VPDB); for Upper Jurassic – Lower Cretaceous δ<sup>18</sup>O values range from – 4.3 to –1.6 ‰ VPDB; for Lower Cretaceous - δ<sup>18</sup>O values range from – 4.5 to –3.4 ‰ VPDB. Carbon isotope composition for Middle Jurassic glendonite concretions δ<sup>13</sup>C values range from – 33.3 to –22.6 ‰ VPDB; for Upper Jurassic – Lower Cretaceous δ<sup>13</sup>C values range from – 25.1 to –18.4 ‰ VPDB; for Lower Cretaceous - δ<sup>13</sup>C values range from – 30.1 to –25.6 ‰ VPDB.</p><p>Based on δ<sup>18</sup>O data we supposed that seawater had a strong influence on ikaite-derived calcite precipitation. Received data coincide with δ<sup>18</sup>O values reported from other Mesozoic glendonites and Quaternary glendonites formed in cold environments. Values of δ<sup>13</sup>C of glendonites are close to bacterial sulfate reduction and/or anaerobic oxidation of methane or organic matter. Glendonites consist of carbonates forming a number of phases which different in phosphorus and magnesium content. Mg-bearing calcium carbonate and dolomite both include framboidal pyrite, which can indicate (1) lack of strong rock transformations activity and (2) presence of sulfate-reduction bacteria in sediments.</p><p>To conclude, Mesozoic climate was generally warm and studied concretions indicate cold climate excursion in Middle Jurassic, Upper Jurassic-Early Cretaceous and Early Cretaceous.</p><p> </p><p>The study was supported by RFBR, project number 20-35-70012.</p>

Nina Creek Group and Lay Range Assemblage, north-central British Columbia: remnants of late Paleozoic oceanic and arc terranes

1997 ◽  
Vol 34 (6) ◽  
pp. 854-874 ◽  
Author(s):  
Filippo Ferri
Keyword(s):  
British Columbia ◽  
North America ◽  
Volcanic Rocks ◽  
Tholeiitic Basalt ◽  
Ocean Floor ◽  
North Central ◽  
Marginal Basin ◽  
The North ◽  
Lower Division ◽  
Ocean Ridge

In north-central British Columbia, a belt of upper Paleozoic volcanic and sedimentary rocks lies between Mesozoic arc rocks of Quesnellia and Ancestral North America. These rocks belong to two distinct terranes: the Nina Creek Group of the Slide Mountain terrane and the Lay Range Assemblage of the Quesnel terrane. The Nina Creek Group is composed of Mississippian to Late Permian argillite, chert, and mid-ocean-ridge tholeiitic basalt, formed in an ocean-floor setting. The sedimentary and volcanic rocks, the Mount Howell and Pillow Ridge successions, respectively, form discrete, generally coeval sequences interpreted as facies equivalents that have been interleaved by thrusting. The entire assemblage has been faulted against the Cassiar terrane of the North American miogeocline. West of the Nina Creek Group is the Lay Range Assemblage, correlated with the Harper Ranch subterrane of Quesnellia. It includes a lower division of Mississippian to Early Pennsylvanian sedimentary and volcanic rocks, some with continental affinity, and an upper division of Permian island-arc, basaltic tuffs and lavas containing detrital quartz and zircons of Proterozoic age. Tuffaceous horizons in the Nina Creek Group imply stratigraphic links to a volcanic-arc terrane, which is inferred to be the Lay Range Assemblage. Similarly, gritty horizons in the lower part of the Nina Creek Group suggest links to the paleocontinental margin to the east. It is assumed that the Lay Range Assemblage accumulated on a piece of continental crust that rifted away from ancestral North America in the Late Devonian to Early Mississippian by the westward migration of a west-facing arc. The back-arc extension produced the Slide Mountain marginal basin in which the Nina Creek Group was deposited. Arc volcanism in the Lay Range Assemblage and other members of the Harper Ranch subterrane was episodic rather than continuous, as was ocean-floor volcanism in the marginal basin. The basin probably grew to a width of hundreds rather than thousands of kilometres.

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