Response of Reef Growth to Sea-Level Changes (Late Miocene, Fortuna Basin, Southeastern Spain)

Palaios ◽  
1995 ◽  
Vol 10 (4) ◽  
pp. 322 ◽  
Author(s):  
Carol Mankiewicz
Keyword(s):  
Sea Level ◽  
Late Miocene ◽  
Reef Growth ◽  
Sea Level Changes ◽  
Southeastern Spain

A pre-cursor extensive Miocene reef system to the Rowley Shoals reefs, Western Australia: evidence for structural control of reef growth or natural hydrocarbon seepage?

2009 ◽  
Vol 49 (1) ◽  
pp. 337 ◽  
Author(s):  
Georgina Ryan ◽  
George Bernardel ◽  
John Kennard ◽  
Andrew T Jones ◽  
Graham Logan ◽  
...  
Keyword(s):  
Sea Level ◽  
Fault Zone ◽  
Western Australia ◽  
Growth Phase ◽  
Late Miocene ◽  
Structural Control ◽  
Middle Miocene ◽  
Reef Growth ◽  
Sea Level Changes ◽  
North West

Numerous Miocene reefs and related carbonate build-ups have been identified in the Rowley Shoals region of the central North West Shelf, offshore Western Australia. The reefs form part of an extensive Miocene reef tract over 1,600 km long, which extended northward into the Browse and Bonaparte basins and southward to North West Cape in the Carnarvon Basin—comparable in length to the modern Great Barrier Reef. Growth of the vast majority of these Miocene reefs failed to keep pace with relative sea-level changes in the latest Miocene, whereas reef growth continued on the central North West Shelf to form the three present-day atolls of the Rowley Shoals: Mermaid, Clerke and Imperieuse reefs. In the Rowley Shoals region, scattered small build-ups and local reef complexes were first established in the Early Miocene, but these build-ups were subsequently terminated at a major Mid Miocene sequence boundary. Widespread buildups and atoll reefs were re-established in the Middle Miocene, and the internal stacking geometries of the reefs appear to relate to distinct growth phases that are correlated with eustatic sea-level fluctuations. These geometries include: a basal aggradational buildup of early Middle Miocene age; a strongly progradational growth phase in the late Middle to early Late Miocene that constructed large reef atolls with infilling lagoon deposits; and a back-stepped aggradational growth phase that formed smaller reef caps in the early–latest Late Miocene. Growth of the majority of the reefs ceased at a major sea-level fall in the Late Miocene (Messinian), and only the reefs of the present-day Rowley Shoals (Mermaid, Clerke and Imperieuse reefs, as well as a drowned shoal to the southwest of Imperieuse Reef) continued to grow after this event. Growth of the Rowley Shoals reefs continued to keep pace with Pliocene-Recent sea-level changes, whereas the surrounding shelf subsided to depths of 230–440 m. We conclude that initial reef growth in the Rowley Shoals region was controlled by transpressional reactivation and structuring of the Mermaid Fault Zone during the early stage of collision between the Australian and Eurasian plates. During this structural reactivation, seabed fault scarps and topographic highs likely provided ideal sites for the initiation of reef growth. The subsequent growth and selective demise of the reefs was controlled by the interplay of eustatic sea-level variations and differential subsidence resulting from continued structural reactivation of the Mermaid Fault Zone. In contrast to models proposed in other regions, there is no direct evidence that active or palaeo hydrocarbon seepage triggered or controlled growth of the Rowley Shoals reefs or their buried Miocene predecessors.

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 Eustatic and tectonic change effects in the reversion of the transcontinental Amazon River drainage system

2016 ◽  
Vol 46 (2) ◽  
pp. 301-328 ◽  
Author(s):  
Mario Vicente Caputo ◽  
Emilio Alberto Amaral Soares
Keyword(s):  
South America ◽  
Atlantic Ocean ◽  
Sea Level ◽  
Late Miocene ◽  
Middle Miocene ◽  
Drainage System ◽  
Sedimentary Basins ◽  
Amazon River ◽  
Drainage Network ◽  
Sea Level Changes

ABSTRACT: The development of the transcontinental Amazon River System involved geological events in the Andes Chain; Vaupés, Purus and Gurupá arches; sedimentary basins of the region and sea level changes. The origin and age of this river have been discussed for decades, and many ideas have been proposed, including those pertaining to it having originated in the Holocene, Pleistocene, Pliocene, Late Miocene, or even earlier times. Under this context, the geology of the sedimentary basins of northern Brazil has been analyzed from the Mesozoic time on, and some clarifications are placed on its stratigraphy. Vaupés Arch, in Colombia, was uplifted together with the Andean Mountains in the Middle Miocene time. In the Cenozoic Era, the Purus Arch has not blocked this drainage system westward to marine basins of Western South America or eastward to the Atlantic Ocean. Also the Gurupá Arch remained high up to the end of Middle Miocene, directing this drainage system westward. With the late subsidence and breaching of the Gurupá Arch and a major fall in sea level, at the beginning of the Late Miocene, the Amazon River quickly opened its pathway to the west, from the Marajó Basin, through deep headward erosion, capturing a vast drainage network from cratonic and Andean areas, which had previously been diverted towards the Caribbean Sea. During this time, the large siliciclastic influx to the Amazon Mouth (Foz do Amazonas) Basin and its fan increased, due to erosion of large tracts of South America, linking the Amazon drainage network to that of the Marajó Basin. This extensive exposure originated the Late Miocene (Tortonian) unconformity, which marks the onset of the transcontinental Amazon River flowing into the Atlantic Ocean.

Clinoform migration patterns of a Late Miocene delta complex in the Danish Central Graben; implications for relative sea-level changes

2009 ◽  
Vol 21 (5) ◽  
pp. 704-720 ◽  
Author(s):  
L. K. Møller ◽  
E. S. Rasmussen ◽  
O. R. Clausen
Keyword(s):  
Sea Level ◽  
Late Miocene ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Migration Patterns

SEA LEVEL CHANGES IN THE NEOGENE OF SOUTHERN VICTORIA

1978 ◽  
Vol 18 (1) ◽  
pp. 64 ◽  
Author(s):  
C. W. Mallett
Keyword(s):  
Grain Size ◽  
Sea Level ◽  
Marine Sediments ◽  
Late Miocene ◽  
Sea Level Change ◽  
Early Miocene ◽  
Sea Level Changes ◽  
Sea Levels ◽  
Level Change ◽  
Gippsland Basin

The distribution and lithology of marine sediments in southern Victoria are related to climatic events and the associated sea level changes. The most extensive transgression on the northern (onshore) margin of the southern Victorian Tertiary basins occurred late in the Early Miocene, with widespread deposition of calcareous muds and localised calcarenites with Lepidocvclina. Shallowing at approximately 14 m.y. affected all southern Victoria, initiating lithological changes in the Otway and Port Phillip Basins, and coinciding with erosion in the Gippsland Basin. Throughout the Late Miocene the grain size of sediments tended to increase and cross-bedded calcarenites became more common, consistent with shallowing deposition and sea withdrawal. By approximately 6 m.y., near the end of the Late Miocene, the sea had completely withdrawn from the onshore areas of southern Victoria.Pliocene and Pleistocene outcrops are scattered and thin, and marine beds are exclusively of nearshore and shallow deposition. For much of this period sea level was lower than at present. High levels in the Pliocene are indicated at approximately 5 m.y. and 3.5 m.y. High sea levels, associated with the rapid alternation of glacial and interglacial periods which typify the Pleistocene Epoch, were initiated late in the Pliocene, close to 2 m.y.Changes to the planktonic foraminiferal faunas parallel the sedimentological responses to sea level change. These suggest that palaeoclimatic events were the main controlling factor in Neogene sea level changes in southern Victoria, and allow differentiation of the eustatic and tectonic controls on sedimentation.

Late Holocene reef growth and relative sea-level changes in Atol das Rocas, equatorial South Atlantic

Coral Reefs ◽  
2005 ◽  
Vol 24 (2) ◽  
pp. 264-272 ◽  
Author(s):  
D. F. M. Gherardi ◽  
D. W. J. Bosence
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
South Atlantic ◽  
Reef Growth ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Holocene Reef

Paleozoic Sea-Level Changes in the Appalachian Basin: Washington, D.C., July 20–24, 1989

10.1029/ft354 ◽  
1989 ◽  
Author(s):  
John M. Dennison ◽  
Edwin J. Anderson ◽  
Jack D. Beuthin ◽  
Edward Cotter ◽  
Richard J. Diecchio ◽  
...  
Keyword(s):  
Sea Level ◽  
Appalachian Basin ◽  
Sea Level Changes
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