Evolution of the early Paleozoic Cordilleran margin of Laurentia: tectonic and eustatic events interpreted from sequence stratigraphy and conodont community patterns

2005 ◽  
Vol 42 (6) ◽  
pp. 999-1031 ◽  
Author(s):  
Shunxin Zhang ◽  
Leanne J Pyle ◽  
Christopher R Barnes
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Passive Margin ◽  
Early Paleozoic ◽  
Relative Sea Level ◽  
Lower Paleozoic ◽  
Community Patterns ◽  
Regional Tectonic ◽  
Laurentian Margin ◽  
Cordilleran Margin

Several field seasons in the Canadian Cordillera have allowed the measurement, description and sampling of over 20 000 m of lower Paleozoic strata from 26 stratigraphic sections across four platform-to-basin transects, with the recovery of over 100 000 conodonts from more than 1200 4–5 kg samples. This work was part of the Lithoprobe Slave – Northern Cordillera Lithospheric Evolution (SNORCLE) project but is also being extended through a Pan-Lithoprobe project to understand the tectonic and eustatic response of much of the Laurentian plate through the early Paleozoic. Based on the abundant field data, the complex stratigraphic framework is interpreted in terms of sequence stratigraphy and a derived relative sea-level curve. Using detailed conodont taxonomic and biostratigraphic results, cluster analysis of conodont distributional data identified an evolving series of conodont communities through space and time. These communities were partitioned across the platform-to-basin gradient and provide an additional sensitive indicator of relative sea-level change. These two independent approaches generated comparable eustatic curves for this Cordilleran Laurentian margin during much of the early Paleozoic and identified some global eustatic events noted by earlier workers. This part of Laurentia was not a simple passive margin during the early Paleozoic, but rather was affected by four main tectonic events complicated by six principal eustatic changes. Some success was achieved in filtering the global and regional tectonic–eustatic effects and in proposing causes for some of the events.

scholarly journals Sequence stratigraphy, chemostratigraphy and facies analysis of Cambrian Series 2 – Series 3 boundary strata in northwestern Scotland

2016 ◽  
Vol 155 (4) ◽  
pp. 865-877 ◽  
Author(s):  
LUKE E. FAGGETTER ◽  
PAUL B. WIGNALL ◽  
SARA B. PRUSS ◽  
YADONG SUN ◽  
ROBERT J. RAINE ◽  
...  
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Carbon Isotope ◽  
Sea Level Changes ◽  
Carbon Isotopic ◽  
Carbonate Carbon ◽  
Carbon Isotope Excursion ◽  
Isotope Record ◽  
Laurentian Margin ◽  
Sequence Boundaries

AbstractGlobally, the Series 2 – Series 3 boundary of the Cambrian System coincides with a major carbon isotope excursion, sea-level changes and trilobite extinctions. Here we examine the sedimentology, sequence stratigraphy and carbon isotope record of this interval in the Cambrian strata (Durness Group) of NW Scotland. Carbonate carbon isotope data from the lower part of the Durness Group (Ghrudaidh Formation) show that the shallow-marine, Laurentian margin carbonates record two linked sea-level and carbon isotopic events. Whilst the carbon isotope excursions are not as pronounced as those expressed elsewhere, correlation with global records (Sauk I – Sauk II boundary andOlenellusbiostratigraphic constraint) identifies them as representing the local expression of the ROECE and DICE. The upper part of the ROECE is recorded in the basal Ghrudaidh Formation whilst the DICE is seen around 30m above the base of this unit. Both carbon isotope excursions co-occur with surfaces interpreted to record regressive–transgressive events that produced amalgamated sequence boundaries and ravinement/flooding surfaces overlain by conglomerates of reworked intraclasts. The ROECE has been linked with redlichiid and olenellid trilobite extinctions, but in NW Scotland,Olenellusis found after the negative peak of the carbon isotope excursion but before sequence boundary formation.

Lower Paleozoic stratigraphic and biostratigraphic correlations in the Canadian Cordillera: implications for the tectonic evolution of the Laurentian margin

2003 ◽  
Vol 40 (12) ◽  
pp. 1739-1753 ◽  
Author(s):  
Leanne J Pyle ◽  
Christopher R Barnes
Keyword(s):  
Tectonic Evolution ◽  
Passive Margin ◽  
Lower Paleozoic ◽  
Early Devonian ◽  
Southern Rocky Mountains ◽  
Peace River ◽  
Regional Correlation ◽  
Laurentian Margin ◽  
Peace River Arch ◽  
Early Late

The ancient Laurentian margin rifted in the latest Neoproterozoic to early Cambrian but appears not to have developed as a simple passive margin through a long, post-rift, drift phase. Stratigraphic and conodont biostratigraphic information from four platform-to-basin transects across the margin has advanced our knowledge of the early Paleozoic evolution of the margin. In northeastern British Columbia, two northern transects span the Macdonald Platform to Kechika Trough and Ospika Embayment, and a third transect spans the parautochthonous Cassiar Terrane. In the southern Rocky Mountains, new conodont biostratigraphic data for the Ordovician succession of the Bow Platform is correlated to coeval basinal facies of the White River Trough. In total, from 26 stratigraphic sections, over 25 km of strata were measured and > 1200 conodont samples were collected that yielded over 100 000 conodont elements. Key zonal species were used for regional correlation of uppermost Cambrian to Middle Devonian strata along the Cordillera. The biostratigraphy temporally constrains at least two periods of renewed extension along the margin, in the latest Cambrian and late Early Ordovician. Alkalic volcanics associated with abrupt facies changes across the ancient shelf break, intervals of slope debris breccia deposits, and distal turbidite flows suggest the margin was characterized by intervals of volcanism, basin foundering, and platform flooding. Siliciclastics in the succession were sourced by a reactivation of tectonic highs, such as the Peace River Arch. Prominent hiatuses punctuate the succession, including unconformities of early Late Ordovician, sub-Llandovery, possibly Early to Middle Silurian and Early Devonian ages.

scholarly journals Depositional environment of the Branch Sandstone and correlative sequences: Late Cretaceous changes in relative sea level in the East Coast Basin of New Zealand

2021 ◽  
Author(s):  
◽  
Lisa McCarthy
Keyword(s):  
Sea Level ◽  
East Coast ◽  
Depositional Environments ◽  
Passive Margin ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sea Level Fluctuations ◽  
The North ◽  
Tasman Sea ◽  
History Of

<p>The Branch Sandstone is located within an overall transgressive, marine sedimentary succession in Marlborough, on the East Coast of New Zealand’s South Island. It has previously been interpreted as an anomalous sedimentary unit that was inferred to indicate abrupt and dramatic shallowing. The development of a presumed short-lived regressive deposit was thought to reflect a change in relative sea level, which had significant implications for the geological history of the Marlborough region, and regionally for the East Coast Basin.  The distribution and lithology of Branch Sandstone is described in detail from outcrop studies at Branch Stream, and through the compilation of existing regional data. Two approximately correlative sections from the East Coast of the North Island (Tangaruhe Stream and Angora Stream) are also examined to provide regional context. Depositional environments were interpreted using sedimentology and palynology, and age control was developed from dinoflagellate biostratigraphy. Data derived from these methods were combined with the work of previous authors to establish depositional models for each section which were then interpreted in the context of relative sea level fluctuations.  At Branch Stream, Branch Sandstone is interpreted as a shelfal marine sandstone, that disconformably overlies Herring Formation. The Branch Sandstone is interpreted as a more distal deposit than uppermost Herring Formation, whilst the disconformity is suggested to have developed during a fall in relative sea level. At Branch Stream, higher frequency tectonic or eustatic sea-level changes can therefore be distinguished within a passive margin sedimentary sequence, where sedimentation broadly reflects subsidence following rifting of the Tasman Sea. Development of a long-lived disconformity at Tangaruhe Stream and deposition of sediment gravity flow deposits at Angora Stream occurred at similar times to the fall in relative sea level documented at the top of the Herring Formation at Branch Stream. These features may reflect a basin-wide relative sea-level event, that coincides with global records of eustatic sea level fall.</p>

Critical view of the concept of sequence stratigraphy

2020 ◽  
Author(s):  
Alexander L. Beisel ◽  
Keyword(s):  
Theoretical Analysis ◽  
Sea Level ◽  
Sequence Stratigraphy ◽  
Relative Sea Level ◽  
Critical View ◽  
Sinusoidal Shape ◽  
Definition Of ◽  
Modern Varieties

Based on a theoretical analysis, the main shortcomings of modern varieties of the concept of sequence stratigraphy are shown: they do not comply with the definition of the relative sea level, which is given by the authors themselves; the nature of tectonic immersion, which cannot have a sinusoidal shape, is not taken into account; the boundaries of sequences, identified as subaerial disagreements on the periphery of the cover, are unlawfully compared with consonant boundaries within the basins. The need for a thorough review of this concept based on the new basic provisions is shown.

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