Chapter 6 The Argentine continental shelf: morphology, sediments, processes and evolution since the Last Glacial Maximum

10.1144/m41.6 ◽  
2014 ◽  
Vol 41 (1) ◽  
pp. 55-68 ◽  
Author(s):  
R. A. Violante ◽  
C. M. Paterlini ◽  
S. I. Marcolini ◽  
I. P. Costa ◽  
J. L. Cavallotto ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals Submarine Geomorphology of the Southwestern Sardinian Continental Shelf (Mediterranean Sea): Insights into the Last Glacial Maximum Sea-Level Changes and Related Environments

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 155
Author(s):  
Giacomo Deiana ◽  
Luciano Lecca ◽  
Rita Teresa Melis ◽  
Mauro Soldati ◽  
Valentino Demurtas ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Sea Level ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Sea Level Changes ◽  
Side Scan Sonar ◽  
Last Glacial ◽  
Depositional Processes ◽  
The Last Glacial Maximum ◽  
The Last Glacial

During the lowstand sea-level phase of the Last Glacial Maximum (LGM), a large part of the current Mediterranean continental shelf emerged. Erosional and depositional processes shaped the coastal strips, while inland areas were affected by aeolian and fluvial processes. Evidence of both the lowstand phase and the subsequent phases of eustatic sea level rise can be observed on the continental shelf of Sardinia (Italy), including submerged palaeo-shorelines and landforms, and indicators of relict coastal palaeo-environments. This paper shows the results of a high-resolution survey on the continental shelf off San Pietro Island (southwestern Sardinia). Multisensor and multiscale data—obtained by means of seismic sparker, sub-bottom profiler chirp, multibeam, side scan sonar, diving, and uncrewed aerial vehicles—made it possible to reconstruct the morphological features shaped during the LGM at depths between 125 and 135 m. In particular, tectonic controlled palaeo-cliffs affected by landslides, the mouth of a deep palaeo-valley fossilized by marine sediments and a palaeo-lagoon containing a peri-littoral thanatocenosis (18,983 ± 268 cal BP) were detected. The Younger Dryas palaeo-shorelines were reconstructed, highlighted by a very well preserved beachrock. The coastal paleo-landscape with lagoon-barrier systems and retro-littoral dunes frequented by the Mesolithic populations was reconstructed.

scholarly journals Interplay between detrital and diagenetic processes since the last glacial maximum on the northwest Iberian continental shelf

2010 ◽  
Vol 73 (3) ◽  
pp. 507-520 ◽  
Author(s):  
Kais Jacob Mohamed ◽  
Daniel Rey ◽  
Belen Rubio ◽  
Federico Vilas ◽  
Thomas Frederichs
Keyword(s):  
Continental Shelf ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Warm Period ◽  
Ice Age ◽  
Magnetic Minerals ◽  
Last Glacial ◽  
Textural Data ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Integrated analyses of magnetic, geochemical and textural data on six cores from the northwestern Iberian continental shelf allowed the reconstruction of the paleoenvironmental evolution of this area since the last glacial maximum (LGM). Four sedimentary units were identified, representing a succession from fluvial and subaerial settings to high and finally low-energy marine deposits subsequent to the post-LGM sea-level rise. The uppermost unit was deposited during the Holocene and its magnetic properties were controlled by the interplay between detrital input and early diagenetic reductive dissolution of magnetic minerals. Identification of a primary steady-state early diagenetic signal allowed the recognition of periods of increased detrital input, bounded by intervals of lower detrital input and intensified reductive diagenesis related to intensified upwelling in the area. These paleoenvironmental alternations are consistent with the climatic evolution of the late Holocene. During the Roman Warm Period and Medieval Warm Period, the combined effect of greater humidity and intense agricultural and mining activities led to a greater erosion and transport of detrital sediments to the shelf. In contrast, enhanced diagenetic reduction intervals, caused by upwelling intensification, were roughly coincident with the colder Dark Ages and the Little Ice Age.

Reconstructions of the past distribution of Testudo graeca mitochondrial lineages in the Middle East and Transcaucasia support multiple refugia since the Last Glacial Maximum

2021 ◽  
pp. 10-17
Author(s):  
Oguz Turkozan
Keyword(s):  
Middle East ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Testudo Graeca ◽  
Last Glacial ◽  
The Past ◽  
Precipitation Seasonality ◽  
Multiple Refugia ◽  
The Last Glacial Maximum ◽  
The Last Glacial

A cycle of glacial and interglacial periods in the Quaternary caused species’ ranges to expand and contract in response to climatic and environmental changes. During interglacial periods, many species expanded their distribution ranges from refugia into higher elevations and latitudes. In the present work, we projected the responses of the five lineages of Testudo graeca in the Middle East and Transcaucasia as the climate shifted from the Last Glacial Maximum (LGM, Mid – Holocene), to the present. Under the past LGM and Mid-Holocene bioclimatic conditions, models predicted relatively more suitable habitats for some of the lineages. The most significant bioclimatic variables in predicting the present and past potential distribution of clades are the precipitation of the warmest quarter for T. g. armeniaca (95.8 %), precipitation seasonality for T. g. buxtoni (85.0 %), minimum temperature of the coldest month for T. g. ibera (75.4 %), precipitation of the coldest quarter for T. g. terrestris (34.1 %), and the mean temperature of the driest quarter for T. g. zarudyni (88.8 %). Since the LGM, we hypothesise that the ranges of lineages have either expanded (T. g. ibera), contracted (T. g. zarudnyi) or remained stable (T. g. terrestris), and for other two taxa (T. g. armeniaca and T. g. buxtoni) the pattern remains unclear. Our analysis predicts multiple refugia for Testudo during the LGM and supports previous hypotheses about high lineage richness in Anatolia resulting from secondary contact.

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