High-Frequency Relative Sea-Level Oscillations in Upper Cretaceous Shelf Clastics of the Alberta Foreland Basin: Possible Evidence for a Glacio-Eustatic Control?

Author(s):  
A. Guy Plint
2021 ◽  
Author(s):  
Krešimir Ruić ◽  
Jadranka Šepić ◽  
Maja Karlović ◽  
Iva Međugorac

<p>Extreme sea levels are known to hit the Adriatic Sea and to occasionally cause floods that produce severe material damage. Whereas the contribution of longer-period (T > 2 h) sea-level oscillations to the phenomena has been well researched, the contribution of the shorter period (T < 2 h) oscillations is yet to be determined. With this aim, data of 1-min sampling resolution were collected for 20 tide gauges, 10 located at the Italian (north and west) and 10 at the Croatian (east) Adriatic coast. Analyses were done on time series of 3 to 15 years length, with the latest data coming from 2020, and with longer data series available for the Croatian coast. Sea level data were thoroughly checked, and spurious data were removed. </p><p>For each station, extreme sea levels were defined as events during which sea level surpasses its 99.9 percentile value. The contribution of short-period oscillations to extremes was then estimated from corresponding high-frequency (T < 2 h) series. Additionally, for four Croatian tide gauge stations (Rovinj, Bakar, Split, and Dubrovnik), for period of 1956-2004, extreme sea levels were also determined from the hourly sea level time series, with the contribution of short-period oscillations visually estimated from the original tide gauge charts.  </p><p>Spatial and temporal distribution of contribution of short-period sea-level oscillations to the extreme sea level in the Adriatic were estimated. It was shown that short-period sea-level oscillation can significantly contribute to the overall extremes and should be considered when estimating flooding levels. </p>


2010 ◽  
Vol 61 (1) ◽  
pp. 29-38
Author(s):  
Damir Bucković ◽  
Maja Martinuš ◽  
Duje Kukoč ◽  
Blanka Tešović ◽  
Ivan Gušić

High-frequency sea-level changes recorded in deep-water carbonates of the Upper Cretaceous Dol Formation (island of Brač, Croatia)The upper part of the Middle Coniacian/Santonian-Middle Campanian deep-water Dol Formation of the island of Brač is composed of countless fine-grained allodapic intercalations deposited in an intraplatform trough. Within the studied section 13 beds can be distinguished, each defined by its lower part built up of dark grey limestone with abundance of branched, horizontally to subhorizontally oriented burrows, and the upper part, in which the light grey to white limestone contains larger burrows, rarely branched, showing no preferential orientation. The lower, dark grey, intensively bioturbated levels are interpreted as intervals formed during high-frequency sea-level highstands, while the upper, light grey-to-white levels are interpreted as intervals formed during the high-frequency sea-level lowstands. Cyclic alternation of these two intervals within the fine-grained allodapic beds is interpreted as the interaction between the amount of carbonate production on the platform margin and the periodicity and intensity of shedding and deposition in the distal part of toe-of-slope environment, which is governed by Milankovitch-band high frequency sea-level changes.


1999 ◽  
Vol 136 (6) ◽  
pp. 681-696 ◽  
Author(s):  
C. J. UNDERWOOD ◽  
S. F. MITCHELL

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.


2014 ◽  
Vol 151 (5) ◽  
pp. 938-955 ◽  
Author(s):  
NICOLAS OLIVIER ◽  
ARNAUD BRAYARD ◽  
EMMANUEL FARA ◽  
KEVIN G. BYLUND ◽  
JAMES F. JENKS ◽  
...  

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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