Correlation of the Aptian Naskapi Member of the Scotian Basin and its regional implications

2018 ◽  
Vol 55 (5) ◽  
pp. 514-535 ◽  
Author(s):  
Isabel Chavez ◽  
David J.W. Piper ◽  
Georgia Pe-Piper
Keyword(s):  
Sea Level ◽  
Black Shales ◽  
Sediment Supply ◽  
Heavy Minerals ◽  
Western Canada ◽  
Great Decrease ◽  
Sea Level Changes ◽  
Sonic Log ◽  
Wireline Logs ◽  
Meguma Terrane

The Naskapi Member of the Logan Canyon Formation, a 150 m thick shale-dominated unit, lies in between sand-dominated units of Upper Missisauga Formation below and the Cree Member above. The great decrease in sediment supply has been suggested as due to tectonic and (or) eustatic sea-level changes. Wireline logs and recent biostratigraphy of 30 wells from the Scotian Shelf and Georges Bank, mudstone geochemistry from the Naskapi and Cree Members, and modal composition and chemical variation of detrital heavy minerals in sandstones were examined to better understand the deposition of the Naskapi Member and its regional implications. Minor sandy intervals at the base of the Naskapi Member were correlated based on gamma and sonic log signatures from the type section in the Cree E-35 well to progressively more distant wells, on the assumption that the sands represent periods of lowered eustatic sea level. Correlation was confirmed by the distribution of highstand black shales in washed cuttings and biostratigraphic markers identified in some wells. The geochemistry of mudstones from the Naskapi Member resembles mudstones sourced from the Meguma Terrane, except for a higher abundance of elements likely reworked in smaller amounts from the Upper Missisauga Formation. Based on the correlation and geochemistry of mudstones and detrital minerals, we suggest the diversion of Sable River through the Gulf of St. Lawrence to either the Orphan Basin or towards western Canada was responsible for the decrease of sediment supply in the Scotian Basin during the deposition of the Naskapi Member shales.

Foraminiferal response to Albian relative sea-level changes in northwestern and central Alberta, Canada

1999 ◽  
Vol 36 (10) ◽  
pp. 1617-1643 ◽  
Author(s):  
Rebecca A Stritch ◽  
Claudia J Schröder-Adams
Keyword(s):  
Sea Level ◽  
Bottom Water ◽  
Gradual Increase ◽  
Western Canada ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sea Level Fluctuations ◽  
Faunal Assemblages ◽  
Water Oxygen ◽  
Southern Alberta

Albian foraminiferal assemblages from three wells in northwestern (Imperial Spirit River No. 1, 12-20-78-6W6), central (AngloHome C&E Fort Augustus No. 1, 7-29-55-21W4), and southern Alberta (Amoco B1 Youngstown, 6-34-30-8W4) provide the basis to track a fluctuating sea-level history in western Canada. Two global second-order marine cycles (Kiowa - Skull Creek and Greenhorn) were punctuated by higher frequency relative sea-level cycles expressed during the time of the Moosebar-Clearwater, Hulcross, Joli Fou, and Mowry seas. A total of 34 genera and 93 subgeneric taxa are recognized in these Albian-age strata. Foraminiferal abundance and species diversity of the latest Albian Mowry Sea were higher than in the early to middle Albian Moosebar-Clearwater and Hulcross seas. The two earliest paleo-seas were shallow embayments of the Boreal Sea, and relative sea-level fluctuations caused variable marine to brackish conditions expressed in a variety of faunal assemblages. Towards the late Albian, relative sea level rose, deepening the basin and establishing increased marine conditions and more favourable habitats for foraminifera. In the deeper Joli Fou Seaway and Mowry Sea, however, reduced bottom water oxygen through stratification or stagnant circulation caused times of diminished benthic faunas. The Bluesky Formation in northwestern Alberta contains the initial transgression of the early Albian Moosebar-Clearwater Sea and is marked by a sudden faunal increase. In contrast, transgression by the late late Albian Mowry Sea was associated with a gradual increase of foraminiferal faunas. Numerous agglutinated species range throughout the entire Albian, absent only at times of basin shallowing. However, each major marine incursion throughout the Albian introduced new taxa.

The arrival of the paleo–Orinoco Delta at Trinidad: The Cruse Formation delta lobes and delivery to deepwater Atlantic

2020 ◽  
Vol 90 (8) ◽  
pp. 938-968
Author(s):  
Ariana Osman ◽  
Ronald J. Steel ◽  
Ryan Ramsook ◽  
Cornel Olariu ◽  
Si Chen
Keyword(s):  
Sea Level ◽  
Late Miocene ◽  
Sediment Supply ◽  
Average Height ◽  
Shelf Edge ◽  
Sea Level Changes ◽  
Orinoco Delta ◽  
Basin Floor ◽  
Shelf Margin ◽  
High Sediment

ABSTRACT Icehouse continental-shelf-margin accretion is typically driven by high-sediment-supply deltas and repeated glacio-eustatic, climate-driven sea-level changes on a ca. 100 ky time scale. The paleo–Orinoco margin is no exception to this, as the paleo–Orinoco River Delta with its high sediment load prograded across Venezuela, then into the Southern and Columbus basins of Trinidad since the late Miocene, depositing a continental-margin sedimentary prism that is > 12 km thick, 200 km wide, and 500 km along dip. The Cruse Formation (> 800 m thick; 3 My duration) records the first arrival of the paleo–Orinoco Delta into the Trinidad area. It then accreted eastwards, outwards onto the Atlantic margin, by shallow to deepwater clinoform increments since the late Miocene and is capped by a major, thick flooding interval (the Lower Forest Clay). Previous research has provided an understanding of the paleo–Orinoco Delta depositional system at seismic and outcrop scales, but a clinoform framework detailing proximal to distal reaches through the main fairway of the Southern Basin has never been built. We integrate data from 58 wells and outcrop observations to present a 3-D illustration of 15 mapped Cruse clinoforms, in order to understand the changing character of the first Orinoco clastic wedge on Trinidad. The clinoforms have an undecompacted average height of 550 m, estimated continental slope of 2.5° tapering to 1°, and a distance from shelf edge to near-base of slope of > 10 km. The clinoform framework shows trajectory changes from strong shelf-margin progradation (C10–C13) to aggradation (C14–C20) and to renewed progradation (C21–24). Cruse margin progradational phases illustrate oblique clinothem geometries that lack well-developed topsets but contain up to 70 m (200 ft) thick, deepwater slope channels. This suggests a high supply of sediment during periods of repeated icehouse rise and fall of eustatic sea level, with fall outpacing subsidence rates at times, and delivery of sand to the deepwater region of the embryonic Columbus channel region. Also, evidence of wholesale shelf-edge collapse and canyon features seen in outcrop strongly suggest that deepwater conduits for sediment dispersal and bypass surfaces for Cruse basin-floor fans do exist. The change to a topset aggradational pattern with a rising shelf trajectory may be linked to increased subsidence associated with eastward migration of the Caribbean plate. The Cruse-margin topsets were dominated by mixed fluvial–wave delta lobes that were effective in delivery of sands to the basin floor. The preservation of a fluvial regime of the delta may have been impacted by basin geometry which partly sheltered the area from the open Atlantic wave energy at the shelf edge. Ultimately, understanding shelf-edge migration style as well as process-regime changes during cross-shelf transits of the delta will help to predict the location of bypassed sands and their delivery to deepwater areas.

scholarly journals River response to climate and sea level changes during the Late Saalian/Early Eemian in northern Poland – a case study of meandering river deposits in the Chłapowo cliff section

Geologos ◽  
2016 ◽  
Vol 22 (1) ◽  
pp. 1-14
Author(s):  
Damian Moskalewicz ◽  
Robert J. Sokołowski ◽  
Stanisław Fedorowicz
Keyword(s):  
Sea Level ◽  
River Sediments ◽  
Luminescence Dating ◽  
Heavy Minerals ◽  
Sea Level Changes ◽  
Point Bar ◽  
Meandering River ◽  
Base Level ◽  
River Deposits ◽  
And Sea Level

Abstract Fluvial sediments in the Chłapowo cliff section were studied in order to reconstruct their palaeoflow conditions and stratigraphical position. Lithofacies, textural and palaeohydraulic analyses as well as luminescence dating were performed so as to achieve the aim of study. Sedimentary successions were identified as a record of point bar cycles. The fluvial environment probably functioned during the latest Saalian, shortly after the retreat of the Scandinavian Ice Sheet. Discharge outflow was directed to the northwest. The river used the older fluvioglacial valley and probably was directly connected to the Eem Sea. Good preservation and strong aggradation of point-bar cycles were related to a rapid relative base level rise. The meandering river sediments recognised showed responses to climate and sea level changes as illustrated by stratigraphical, morphological and sedimentological features of the strata described. The present study also revealed several insights into proper interpretation of meandering fluvial successions, in which the most important were: specific lithofacies assemblage of GSt (St, Sp) → Sl → SFrc → Fm (SFr) and related architectural elements: channel/sandy bedforms CH/SB → lateral accretion deposits LA → floodplain fines with crevasse splays FF (CS); upward-fining grain size and decreasing content of denser heavy minerals; estimated low-energy flow regime with a mean depth of 1.6–3.3 m, a Froude number of 0.2–0.4 and a sinuosity of 1.5.

scholarly journals Clastic facies models, a personal perspective

2001 ◽  
Vol 48 ◽  
pp. 101-115
Author(s):  
Harold G. Reading
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Sedimentary Rocks ◽  
Sediment Supply ◽  
Personal Perspective ◽  
Sea Level Changes ◽  
Ancient Rock ◽  
Tectonic Movements ◽  
Over Time ◽  
Facies Models

Facies models evolved from classifications that were mainly descriptive, based on observable, measureable features such as the composition and texture of sedimentary rocks. As our understanding of sedimentary processes expanded, genetic facies models were developed based on the inferred process of formation. Since individual facies cannot be interpreted in isolation, they must be studied with reference to their neighbours, emphasizing the association of facies and sequences, in particular those that coarsen and fine upward. Environmental facies models are based on the interaction of studies on modern environments and ancient rock facies. Earlier facies models tended to invoke intrinsic, autocyclic controls. The advent of sequence stratigraphy led to greater emphasis on the surfaces that separate sequences and to external allocyclic controls. These were, initially, sea-level changes; later, changes in climate, tectonic movements and sediment supply were invoked. Over time, simple, all embracing models have given way to increasingly complex ones as our knowledge of the variability of nature has increased. Complex though these models are, they are only simplifications of reality. In nature there are no models and the majority of past environments differed in some respect from any modern environment. Each environment and rock sequence is unique.

Strata sequence and paleochannel response to tectonic, sea-level, and Asian monsoon variability since the late Pleistocene in the South Yellow Sea

2019 ◽  
Vol 92 (2) ◽  
pp. 450-468 ◽  
Author(s):  
Liyan Wang ◽  
Guangxue Li ◽  
Jishang Xu ◽  
Yong Liu ◽  
Lulu Qiao ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Pleistocene ◽  
Yellow Sea ◽  
Yellow River ◽  
Seismic Profile ◽  
Sediment Supply ◽  
The Yellow Sea ◽  
South Yellow Sea ◽  
Sea Level Changes ◽  
Quaternary Period

AbstractThe continental shelf strata provide information regarding sea-level fluctuation and climate changes in the Quaternary period. A 5831.47-km-long high-resolution seismic profile and borehole core (YS01) were acquired to reconstruct the evolutionary history of the strata in South Yellow Sea (SYS) during the late Pleistocene. The strata recorded three transgression events (HI, HII, and HIII) and three stages of paleochannel development (LI, LII, and LIII). Based on the distribution, thickness, and volume of the strata formed in the three transgressions, we concluded that the scale of the three transgressions during the late Pleistocene was HIII, HI, and HII, in descending order. In addition, our data show that the Yellow River extended to the Yellow Sea Trough during the last glacial maximum. The influence of the tectonic framework on sedimentation in the SYS was completely concealed by sea-level changes and sediment supply in the late Pleistocene (~Marine Isotope Stage 5). Since then, the accommodation space, a crucial prerequisite for sedimentation, has been controlled solely by sea-level changes in the SYS. Furthermore, two “source to sink” models of the neritic shelf in the marine and terrestrial environments were established, including high sea-level and shelf-exposure models.

scholarly journals Black shale deposition during Toarcian super-greenhouse driven by sea level

2013 ◽  
Vol 9 (6) ◽  
pp. 2703-2712 ◽  
Author(s):  
M. Hermoso ◽  
F. Minoletti ◽  
P. Pellenard
Keyword(s):  
Organic Carbon ◽  
Water Column ◽  
Sea Level ◽  
Carbon Isotope ◽  
Carbon Isotopes ◽  
Black Shale ◽  
Black Shales ◽  
Positive Trend ◽  
Sea Level Changes ◽  
Organic Carbon Burial

Abstract. One of the most elusive aspects of the Toarcian oceanic anoxic event (T-OAE) is the paradox between carbon isotopes that indicate intense global primary productivity and organic carbon burial at a global scale, and the delayed expression of anoxia in Europe. During the earliest Toarcian, no black shales were deposited in the European epicontinental seaways, and most organic carbon enrichment of the sediments postdated the end of the overarching positive trend in the carbon isotopes that characterises the T-OAE. In the present study, we have attempted to establish a sequence stratigraphic framework for Early Toarcian deposits recovered from a core drilled in the Paris Basin using a combination of mineralogical (quartz and clay relative abundance) and geochemical (Si, Zr, Ti and Al) measurements. Combined with the evolution in redox sensitive elements (Fe, V and Mo), the data suggest that expression of anoxia was hampered in European epicontinental seas during most of the T-OAE (defined by the positive carbon isotope trend) due to insufficient water depth that prevented stratification of the water column. Only the first stratigraphic occurrence of black shales in Europe corresponds to the "global" event. This interval is characterised by >10% Total Organic Carbon (TOC) content that contains relatively low concentration of molybdenum compared to subsequent black shale horizons. Additionally, this first black shale occurrence is coeval with the record of the major negative Carbon Isotope Excursion (CIE), likely corresponding to a period of transient greenhouse intensification likely due to massive injection of carbon into the atmosphere–ocean system. As a response to enhanced weathering and riverine run-off, increased fresh water supply to the basin may have promoted the development of full anoxic conditions through haline stratification of the water column. In contrast, post T-OAE black shales during the serpentinum and bifrons Zones were restricted to epicontinental seas (higher Mo to TOC ratios) during a period of relative high sea level, and carbon isotopes returning to pre-T-OAE values. Comparing palaeoredox proxies with the inferred sequence stratigraphy for Sancerre suggests that episodes of short-term organic carbon enrichment were primarily driven by third-order sea level changes. These black shales exhibit remarkably well-expressed higher-frequency cyclicities in the oxygen availability in the water column whose nature has still to be determined through cyclostratigraphic analysis.

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