PROTEROZOIC, PERMO-CARBONIFEROUS AND PLEISTOCENE GLACIAL CYCLES AND CYCLIC SEDIMENTATION IN RELATION TO OIL SEARCH

1978 ◽  
Vol 18 (1) ◽  
pp. 83
Author(s):  
R. C. Sprigg
Keyword(s):  
Sea Level ◽  
Sea Level Changes ◽  
Glacial Cycles ◽  
Hydrocarbon Source Rock ◽  
Climatic Fluctuations ◽  
Upper Carboniferous ◽  
Sea Floor ◽  
Sedimentary Sequences ◽  
Upper Proterozoic ◽  
Continental Ice Sheets

The Australian Upper Proterozoic, Permo-Carboniferous and Pleistocene glacial epochs were each notable for well -developed examples of glacially-induced, cyclical sedimentation. The Pennsylvanian (Upper Carboniferous) of North America was similarly characterized by cyclothems of probably related origin. Both the foregoing Pennsylvanian and the Australian Permain contain much of the world's coal. Both are significant sources also of hydrocarbons and constitute some of the more prolific hydrocarbon resources on both continents.Around the world, Quaternary sea-floor and terrestrial sedimentary sequences reveal increasing evidence of comparable climatic fluctuations and related sea-level influenced sedimentary deposition. Such fluctuations relate primarily to alternate waxing and waning of contemporary continental ice sheets. Astronomic cycles influenced principally by the varying obliquity of the ecliptic (earth's axial tilt), and the precession of the equinoxes, appear to offer primary climatic controls. Milankovitch -type astronomic radiation cycles almost certainly apply.Prominent sedimentary cycles characterising parts of the Australian Quaternary succession relate directly to repetitive climatic and sea-level changes. In turn, these are related back to Permo-Carboniferous sedimentary deposition as it influenced coal formation, the development of hydrocarbon source rock and a range of sand reservoirs as they bear on oil exploration.

Sea level response to Quartenary erosion and deposition in Scandinavia 

2021 ◽  
Author(s):  
Gustav Pallisgaard-Olesen ◽  
Vivi Kathrine Pedersen ◽  
Natalya Gomez
Keyword(s):  
Sea Level ◽  
Sea Level Changes ◽  
Glacial Cycles ◽  
Glacial Erosion ◽  
Erosion And Deposition ◽  
Late Pliocene ◽  
Glacial Origin ◽  
Sediment Deposits ◽  
Mass Redistribution ◽  
Global Sea Level

<div> <p>The landscape in western Scandinavia has undergone dramatic changes through numerous glaciations during the Quaternary. These changes in topography and in the volumes of offshore sediment deposits, have caused significant isostatic adjustments and local sea level changes, owing to erosional unloading and depositional loading of the lithosphere. Mass redistribution from erosion and deposition also has the potential to cause significant pertubations of the geoid, resulting in additional sea-level changes. The combined sea-level response from these processes, is yet to be investigated in detail for Scandinavia.</p> </div><div> <p>In this study we estimate the total sea level change from late-Pliocene- Quaternary glacial erosion and deposition in the Scandinavian region, using a gravitationally self-consistent global sea level model that includes the full viscoelastic response of the solid Earth to surface loading and unloading. In addition to the total late Pliocene-Quaternary mass redistribution, we <span>also </span>estimate transient sea level changes related specifically to the two latest glacial cycles.</p> </div><div> <p>We utilize existing observations of offshore sediment thicknesses of glacial origin, and combine these with estimates of onshore glacial erosion and estimates of erosion on the inner shelf. Based on these estimates, we can define mass redistribution and construct a preglacial landscape setting.</p> </div><div> <p>Our preliminary results show <span>perturbations of</span> the local sea level up to ∼ 200 m since<span> the</span> late-Pliocene in the Norwegian Sea, suggesting that erosion and deposition ha<span>ve</span> influenced the local paleo sea level history in Scandinavia significantly.</p> </div>

Clay mineral distribution related to rift activity, sea-level changes and paleoceanography in the Cretaceous of the Atlantic Ocean

Clay Minerals ◽  
1993 ◽  
Vol 28 (1) ◽  
pp. 61-84 ◽  
Author(s):  
M. Thiry ◽  
T. Jacquin
Keyword(s):  
Atlantic Ocean ◽  
Sea Level ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Deep Sea ◽  
Depositional Environments ◽  
Sea Level Changes ◽  
Sea Floor ◽  
Deep Sea Sediments ◽  
Bottom Waters

AbstractThe distribution of clay minerals from the N and S Atlantic Cretaceous deep-sea sediments is related to rifting, sea-floor spreading, sea-level variations and paleoceanography. Four main clay mineral suites were identified: two are inherited and indicative of ocean geodynamics, whereas the others result from transformation and authigenesis and are diagnostic of Cretaceous oceanic depositional environments. Illite and chlorite, together with interstratified illite-smectite and smectite occur above the sea-floor basalts and illustrate the contribution of volcanoclastic materials of basaltic origin to the sediments. Kaolinite, with variable amounts of illite, chlorite, smectite and interstratified minerals, indicates detrital inputs from continents near the platform margins. Kaolinite decreases upward in the series due to open marine environments and basin deepening. It may increase in volume during specific time intervals corresponding to periods of falling sea-level during which overall facies regression and erosion of the surrounding platforms occurred. Smectite is the most abundant clay mineral in the Cretaceous deep-sea sediments. Smectite-rich deposits correlate with periods of relatively low sedimentation rates. As paleoweathering profiles and basal deposits at the bottom of Cretaceous transgressive formations are mostly kaolinitic, smectite cannot have been inherited from the continents. Smectite is therefore believed to have formed in the ocean by transformation and recrystallization of detrital materials during early diagenesis. Because of the slow rate of silicate reactions, transformation of clay minerals requires a long residence time of the particles at the water/sediment interface; this explains the relationships between the observed increases in smectite with long-term sea-level rises that tend to starve the basinal settings of sedimentation. Palygorskite, along with dolomite, is relatively common in the N and S Atlantic Cretaceous sediments. It is not detrital because correlative shelf deposits are devoid of palygorskite. Palygorskite is diagnostic of Mg-rich environments and is indicative of the warm and hypersaline bottom waters of the Cretaceous Atlantic ocean.

scholarly journals Aquifer-eustasy as the main driver of short-term sea-level fluctuations during Cretaceous hothouse climate phases

2019 ◽  
Vol 498 (1) ◽  
pp. 9-38 ◽  
Author(s):  
Benjamin Sames ◽  
M. Wagreich ◽  
C. P. Conrad ◽  
S. Iqbal
Keyword(s):  
Sea Level ◽  
Phase Relationship ◽  
Sea Level Changes ◽  
Short Term ◽  
Groundwater Levels ◽  
Sequence Stratigraphic ◽  
Sea Level Fluctuations ◽  
Minimum Estimate ◽  
Underlying Mechanisms ◽  
Continental Ice Sheets

AbstractA review of short-term (<3 myr: c. 100 kyr to 2.4 myr) Cretaceous sea-level fluctuations of several tens of metres indicates recent fundamental progress in understanding the underlying mechanisms for eustasy, both in timing and in correlation. Cretaceous third- and fourth-order hothouse sea-level changes, the sequence-stratigraphic framework, are linked to Milankovitch-type climate cycles, especially the longer-period sequence-building bands of 405 kyr and 1.2 myr. In the absence of continental ice sheets during Cretaceous hothouse phases (e.g. Cenomanian–Turonian), growing evidence indicates groundwater-related sea-level cycles: (1) the existence of Milankovitch-type humid-arid climate oscillations, proven via intense humid weathering records during times of regression and sea-level lowstands; (2) missing or inverse relationships of sea-level and the marine δ18O archives, i.e. the lack of a pronounced positive excursion, cooling signal during sea-level lowstands; and (3) the anti-phase relationship of sea and lake levels, attesting to high groundwater levels and charged continental aquifers during sea-level lowstands. This substantiates the aquifer-eustasy hypothesis. Rates of aquifer-eustatic sea-level change remain hard to decipher; however, reconstructions range from a very conservative minimum estimate of 0.04 mm a−1 (longer time intervals) to 0.7 mm a−1 (shorter, probably asymmetric cycles). Remarkably, aquifer-eustasy is recognized as a significant component for the Anthropocene sea-level budget.

PISM paleo simulations of the Antarctic Ice Sheet over the last two glacial cycles

2020 ◽  
Author(s):  
Torsten Albrecht ◽  
Ricarda Winkelmann ◽  
Anders Levermann
Keyword(s):  
Boundary Conditions ◽  
Sea Level ◽  
Ice Sheet ◽  
Sea Level Changes ◽  
Glacial Cycles ◽  
Antarctic Ice Sheet ◽  
History Of ◽  
Global Sea Level ◽  
Glacial Time ◽  
The Antarctic

&lt;p&gt;Simulations of the glacial-interglacial history of the Antarctic Ice Sheet provide insights into dynamic threshold behavior and estimates of the ice sheet's contributions to global sea-level changes, for the past, present and future. However, boundary conditions are weakly constrained, in particular at the interface of the ice-sheet and the bedrock. We use the Parallel Ice Sheet Model (PISM) to investigate the dynamic effects of different choices of input data and of various parameterizations on the sea-level relevant ice volume. We evaluate the model's transient sensitivity to corresponding parameter choices and to different boundary conditions over the last two glacial cycles and provide estimates of involved uncertainties. We also present isolated and combined effects of climate and sea-level forcing on glacial time scales.&amp;#160;&lt;/p&gt;

The sedimentary record of climatic variation in the southern North Sea

1988 ◽  
Vol 318 (1191) ◽  
pp. 523-537 ◽  
Keyword(s):  
Sea Level ◽  
North Sea ◽  
Climatic Changes ◽  
Sea Level Changes ◽  
Offshore Area ◽  
Sea Levels ◽  
Indirect Response ◽  
Southern North Sea ◽  
Sedimentary Sequences ◽  
Glaciofluvial Deposits

The sedimentary sequence on the shelf of the southern North Sea records Quaternary climatic changes in two ways. They are indicated directly by moraine and glaciofluvial deposits from the Elsterian, Saalian and Weichselian glacial periods when the British and the Scandinavian ice sheets covered parts of the area. An indirect response to the climate is indicated by sea-level changes. Phases of cooling are characterized by regressions and low sea-level stands; phases of warming are indicated by marine transgressions and high sea levels during the Holsteinian, Eemian and Holocene periods. The seismic characteristics of the different lithological units, the sedimentary sequences and their fossil content are described for the offshore area and the adjacent coastal zone. This provides a record of the interaction of sedimentary processes and the palaeogeographic development as a response to climatic changes.

scholarly journals A Recent Worldwide Sinking of Ocean-level

1920 ◽  
Vol 57 (6) ◽  
pp. 246-261 ◽  
Author(s):  
Reginald A. Daly
Keyword(s):  
Sea Level ◽  
Sea Water ◽  
Ocean Basin ◽  
Sea Level Changes ◽  
Geological Time ◽  
Sea Floor ◽  
Crustal Movements ◽  
Centre Of Gravity ◽  
Ocean Level ◽  
Local Uplift

LOCAL uplift and local sinking of the earth's surface have been fully demonstrated for past geological epochs. The amounts of these movements have generally been stated with reference to the present sea-level, and for the greater movements the statements of magnitudes are not seriously impaired by the fact that general sea-level itself has been shifting, upwards and downwards, through geological time. Among the causes for general or “eustatic” shifts of sea-level are: appropriate crustal movements whereby the volume of the ocean basin has been changed; delta-building and volcanic eruption on the sea-floor, the displacement of sea-water not being compensated by crustal sinking; volcanic addition of new water to the ocean; subtraction of water which becomes chemically bound during the alteration of rocks; glaciation on land, lowering sea-level by the abstraction of water from the ocean; deglaciation on land, raising sea-level; changes in the earth's centre of gravity and in her speed of rotation.

scholarly journals The roles of aridification and sea level changes in the diversification and persistence of freshwater fish lineages

2020 ◽  
Author(s):  
Sean J Buckley ◽  
Chris Brauer ◽  
Peter Unmack ◽  
Michael Hammer ◽  
Luciano B. Beheregaray
Keyword(s):  
Freshwater Fish ◽  
Sea Level ◽  
Climatic Changes ◽  
Sea Level Changes ◽  
Glacial Cycles ◽  
Biogeographic History ◽  
Australian Continent ◽  
History Of ◽  
Australian Freshwater ◽  
And Sea Level

ABSTRACTWhile the influence of Pleistocene climatic changes on divergence and speciation has been well-documented across the globe, complex spatial interactions between hydrology and eustatics over longer timeframes may also determine species evolutionary trajectories. Within the Australian continent, glacial cycles were not associated with changes in ice cover and instead largely resulted in fluctuations from moist to arid conditions across the landscape. Here, we investigate the role of hydrological and coastal topographic changes brought about by Plio-Pleistocene climatic changes on the biogeographic history of a small Australian freshwater fish, the southern pygmy perch Nannoperca australis. Using 7,958 ddRAD-seq (double digest restriction-site associated DNA) loci and 45,104 filtered SNPs, we combined phylogenetic, coalescent and species distribution analyses to investigate the relative roles of aridification, sea level and tectonics and their associated biogeographic changes across southeast Australia. Sea-level changes since the Pliocene and reduction or disappearance of large waterbodies throughout the Pleistocene were determining factors in strong divergence across the clade, including the initial formation and maintenance of a cryptic species, N. ‘flindersi’. Isolated climatic refugia and fragmentation due to lack of connected waterways maintained the identity and divergence of inter- and intraspecific lineages. Our historical findings suggest that predicted increases in aridification and sea level due to anthropogenic climate change might result in markedly different demographic impacts, both spatially and across different landscape types.

scholarly journals Exploitation of Beach Sand Minerals in the Offshore Areas – Legal perspective in the light of MMDR Act, 1957 and OAMDR Act, 2002

2021 ◽  
Vol 38 (2) ◽  
pp. 85-88
Author(s):  
Iqbal Basha ◽  
Rohit Jaiswal ◽  
Rajan Chopra ◽  
Eric D'Cruz ◽  
M B Verma
Keyword(s):  
Sea Level ◽  
Coastal Areas ◽  
Beach Sand ◽  
Coastal Plains ◽  
Sea Level Changes ◽  
Sea Floor ◽  
The Past ◽  
Mineral Development ◽  
Legal Perspective ◽  
The Government

Beach Sand Minerals (BSM) form by weathering and erosion of the rocks in the hinterland which are liberated, disintegrate by various processes and, are transportation by the streams to the sites of deposition (coastal plains). These minerals get concentrated along the coastal areas due to constant winnowing by wave action. It is well documented that sea level changes have occurred along the coastal areas at different points of time whose signatures on land can be seen in the form of palaeo-strandline occurring up to 15-20 km from the present day coast. On a similar analogy and in view of bathymetric profile of the sea floor, BSM deposits are expected in the offshore areas as well, in continuity to onshore deposits, which possibly are the submerged onshore deposits of the past. Mineral Concessions in respect of onshore BSM deposits are governed with the Mines and Minerals Development and Regulation (MMDR) Act, 1957 and those in the offshore are governed as per the Offshore Areas Mineral Development and Regulation (OAMDR) Act, 2002 and the rules thereunder respectively. This paper deals with various provisions of these Acts and recent policies of the Government to harmonize mineral concession in offshore areas in line with the onshore BSM deposits.

scholarly journals Glacial-cycle simulations of the Antarctic Ice Sheet with the Parallel Ice Sheet Model (PISM) – Part 1: Boundary conditions and climatic forcing

2020 ◽  
Vol 14 (2) ◽  
pp. 599-632 ◽  
Author(s):  
Torsten Albrecht ◽  
Ricarda Winkelmann ◽  
Anders Levermann
Keyword(s):  
Boundary Conditions ◽  
Sea Level ◽  
Ice Sheet ◽  
Companion Paper ◽  
Sea Level Changes ◽  
Glacial Cycle ◽  
Glacial Cycles ◽  
Climatic Forcing ◽  
Antarctic Ice Sheet ◽  
The Antarctic

Abstract. Simulations of the glacial–interglacial history of the Antarctic Ice Sheet provide insights into dynamic threshold behavior and estimates of the ice sheet's contributions to global sea-level changes for the past, present and future. However, boundary conditions are weakly constrained, in particular at the interface of the ice sheet and the bedrock. Also climatic forcing covering the last glacial cycles is uncertain, as it is based on sparse proxy data. We use the Parallel Ice Sheet Model (PISM) to investigate the dynamic effects of different choices of input data, e.g., for modern basal heat flux or reconstructions of past changes of sea level and surface temperature. As computational resources are limited, glacial-cycle simulations are performed using a comparably coarse model grid of 16 km and various parameterizations, e.g., for basal sliding, iceberg calving, or for past variations in precipitation and ocean temperatures. In this study we evaluate the model's transient sensitivity to corresponding parameter choices and to different boundary conditions over the last two glacial cycles and provide estimates of involved uncertainties. We also discuss isolated and combined effects of climate and sea-level forcing. Hence, this study serves as a “cookbook” for the growing community of PISM users and paleo-ice sheet modelers in general. For each of the different model uncertainties with regard to climatic forcing, ice and Earth dynamics, and basal processes, we select one representative model parameter that captures relevant uncertainties and motivates corresponding parameter ranges that bound the observed ice volume at present. The four selected parameters are systematically varied in a parameter ensemble analysis, which is described in a companion paper.

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