Modeling carbonate microfacies in the context of high-frequency dynamic relative sea-level and environmental changes

The mid-Cretaceous sediments of northeast England were deposited at the western margin of the southern North Sea Basin, with sedimentation occurring in a range of tectonic settings. Detailed analysis of the areal distribution and sedimentary facies of Aptian to earliest Cenomanian sediments has allowed the pattern of onlap onto the Market Weighton structural high and changes in relative sea level to be documented. Successive onlap episodes during the Early Aptian, Late Aptian and Early Albian culminated in the final flooding of the structure during the Late Albian (varicosum Subzone). Sea-level curves generated from coastal onlap patterns are difficult to relate to published ‘global’ sea-level curves due to the high frequency of the fluctuations in relative sea level observed. Despite this, detailed correlation and analysis of sedimentological events suggest that even the most expanded, basinal succession is relatively incomplete. This study has also shown that the change from dominantly syn-tectonic to dominantly post-tectonic sedimentation style occurred in the late Early Albian.

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Sea-level fluctuations in the late Middle Permian estimated from palaeosols of the Sichuan Basin, SW China

Geological Magazine ◽

10.1017/s0016756819001481 ◽

2020 ◽

Vol 157 (8) ◽

pp. 1333-1348

Author(s):

Jun Li ◽

Zhong Han ◽

Xingyue Wen ◽

Gregory J. Retallack ◽

Chengmin Huang

Keyword(s):

Sea Level ◽

Sichuan Basin ◽

Chemical Properties ◽

Middle Permian ◽

Sea Level Changes ◽

Yangtze Craton ◽

Relative Sea Level ◽

Carbonate Microfacies ◽

Additional Tool ◽

Sea Level Fluctuations

AbstractTwo upper Middle Permian palaeosols, consisting of coal and pyrite intercalated with a 20 cm thick limestone, were found near Mount Emei in the SW Sichuan Basin, China. The macro- and micromorphology and physico-chemical properties, in conjunction with the mineralogical composition of the palaeosol horizons were investigated. This type of palaeosol is common within the Permian intertidal facies of the Upper Yangtze Craton. The section reflects fluctuations within the range of 0–25 m in relative sea-level, with the depositional environment changing from shallow-marine to littoral, followed by tidal-flat to littoral, and finally to continental volcanic rocks, based on a combination of palaeopedological and carbonate microfacies analyses. Such short-term relative sea-level fluctuations in late Middle Permian times in the SW Sichuan Basin of South China are consistent with the long-term falling trend on a global scale in late Middle Permian times, and may be related to regionally variable subsidence and global cooling. The combination of coastal palaeosol and carbonate microfacies analyses is proposed as an additional tool for estimating the amplitude of sea-level changes.

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Influence of low amplitude/high frequency relative sea-level changes in a wave-dominated estuary (Miocene), São Luis Basin, northern Brazil

Sedimentary Geology ◽

10.1016/s0037-0738(00)00046-4 ◽

2000 ◽

Vol 133 (3-4) ◽

pp. 295-324 ◽

Cited By ~ 27

Author(s):

D de Fátima Rossetti

Keyword(s):

Sea Level ◽

High Frequency ◽

Sea Level Changes ◽

Relative Sea Level ◽

Northern Brazil ◽

Low Amplitude

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Smithian shoreline migrations and depositional settings in Timpoweap Canyon (Early Triassic, Utah, USA)

Geological Magazine ◽

10.1017/s0016756813000988 ◽

2014 ◽

Vol 151 (5) ◽

pp. 938-955 ◽

Cited By ~ 18

Author(s):

NICOLAS OLIVIER ◽

ARNAUD BRAYARD ◽

EMMANUEL FARA ◽

KEVIN G. BYLUND ◽

JAMES F. JENKS ◽

...

Keyword(s):

Sea Level ◽

High Frequency ◽

Depositional Environments ◽

Small Scale ◽

Early Triassic ◽

Relative Sea Level ◽

Depositional Sequence ◽

Sea Level Fluctuations ◽

Stacking Pattern ◽

Shallow Subtidal

AbstractIn Timpoweap Canyon near Hurricane (Utah, USA), spectacular outcrop conditions of Early Triassic rocks document the geometric relationships between a massive Smithian fenestral-microbial unit and underlying, lateral and overlying sedimentary units. This allows us to reconstruct the evolution of depositional environments and high-frequency relative sea-level fluctuations in the studied area. Depositional environments evolved from a coastal plain with continental deposits to peritidal settings with fenestral-microbial limestones, which are overlain by intertidal to shallow subtidal marine bioclastic limestones. This transgressive trend of a large-scale depositional sequence marks a long-term sea-level rise that is identified worldwide after the Permian–Triassic boundary. The fenestral-microbial sediments were deposited at the transition between continental settings (with terrigenous deposits) and shallow subtidal marine environments (with bioturbated and bioclastic limestones). Such a lateral zonation questions the interpretation of microbial deposits as anachronistic and disaster facies in the western USA basin. The depositional setting may have triggered the distribution of microbial deposits and contemporaneous marine biota. The fenestral-microbial unit is truncated by an erosional surface reflecting a drop in relative sea level at the scale of a medium depositional sequence. The local inherited topography allowed the recording of small-scale sequences characterized by clinoforms and short-distance lateral facies changes. Stratal stacking pattern and surface geometries allow the reconstruction of relative sea-level fluctuations and tracking of shoreline migrations. The stacking pattern of these small-scale sequences and the amplitude of corresponding high-frequency sea-level fluctuations are consistent with climatic control. Large- and medium-scale sequences suggest a regional tectonic control.

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