scholarly journals Distinct phases of eustatism and tectonics control the late Quaternary landscape evolution at the southern coastline of Crete

2016 ◽  
Author(s):  
Vasiliki Mouslopoulou ◽  
John Begg ◽  
Alexander Fülling ◽  
Daniel Moraetis ◽  
Panagiotis Partsinevelos ◽  
...  
Keyword(s):  
Landscape Evolution ◽  
Late Quaternary ◽  
Eastern Mediterranean ◽  
Vertical Movement ◽  
Tectonic Uplift ◽  
Alluvial Fan ◽  
Contributing Factors ◽  
River Incision ◽  
Coastal Landscapes ◽  
Uplift Rates

Abstract. The extent to which climate, eustacy and tectonics interact to shape the late Quaternary landscape is poorly known. Alluvial fans often provide useful indexes that allow decoding the information recorded on complex coastal landscapes, such as those of Eastern Mediterranean. In this paper we analyse and date (using optically stimulated luminescence – OSL) a double alluvial-fan system in Crete, an island straddling the forearc of the Hellenic subduction margin, in order to constrain the timing of, and quantify the contributing factors to, its landscape evolution. The studied alluvial system is unique because each of its two juxtaposed fans records individual phases of alluvial and marine incision, providing, thus, unprecedented resolution in the formation and evolution of its landscape. Specifically, our analysis shows that the fan sequence at Domata developed during the last glaciation (Marine Isotope Stage 3; 57–29 kyr) due to five distinct stages of marine transgressions and regressions and associated river incision, as a response to climatic changes and tectonic uplift at rates of ~ 2.2 mm/yr. Comparison of our results with published tectonic uplift rates from Crete shows, however, that vertical movement on Crete was minimal during 20–50 kyr BP and mot uplift was accrued during the last 20 kyr. This implies that eustacy and tectonism impacted on the landscape at Domata over mainly distinct time-intervals (e.g. sequentially and not synchronously), forming and preserving the coastal landforms, respectively.

scholarly journals Distinct phases of eustatic and tectonic forcing for late Quaternary landscape evolution in southwest Crete, Greece

2017 ◽  
Vol 5 (3) ◽  
pp. 511-527 ◽  
Author(s):  
Vasiliki Mouslopoulou ◽  
John Begg ◽  
Alexander Fülling ◽  
Daniel Moraetis ◽  
Panagiotis Partsinevelos ◽  
...  
Keyword(s):  
Landscape Evolution ◽  
Late Quaternary ◽  
Eastern Mediterranean ◽  
Tectonic Uplift ◽  
Alluvial Fan ◽  
Sea Level Fluctuations ◽  
River Incision ◽  
Infrared Stimulated Luminescence ◽  
Coastal Landscapes ◽  
Uplift Rates

Abstract. The extent to which climate, eustasy and tectonics interact to shape the late Quaternary landscape is poorly known. Alluvial fans often provide useful indexes that allow the decoding of information recorded on complex coastal landscapes, such as those of the eastern Mediterranean. In this paper we analyse and date (using infrared stimulated luminescence (IRSL) dating) a double alluvial fan system on southwest Crete, an island straddling the forearc of the Hellenic subduction margin, in order to constrain the timing and magnitude of its vertical deformation and discuss the factors contributing to its landscape evolution. The studied alluvial system is exceptional because each of its two juxtaposed fans records individual phases of alluvial and marine incision, thus providing unprecedented resolution in the formation and evolution of its landscape. Specifically, our analysis shows that the fan sequence at Domata developed during Marine Isotope Stage (MIS) 3 due to five distinct stages of marine transgressions and regressions and associated river incision, in response to sea-level fluctuations and tectonic uplift at averaged rates of  ∼ 2.2 mm yr−1. Interestingly, comparison of our results with published tectonic uplift rates from western Crete shows that uplift during 20–50 kyr BP was minimal (or even negative). Thus, most of the uplift recorded at Domata must have occurred in the last 20 kyr. This implies that eustasy and tectonism impacted the landscape at Domata over mainly distinct time intervals (e.g. sequentially and not synchronously), with eustasy forming and tectonism preserving the coastal landforms.

scholarly journals Spatial Variations of Tectonic Uplift - Subducting Plate Effects on the Guerrero Forearc, Mexico

2021 ◽  
Vol 8 ◽  
Author(s):  
María Teresa Ramírez-Herrera ◽  
Krzysztof Gaidzik ◽  
Steven L. Forman
Keyword(s):  
Subduction Zones ◽  
Spatial Variations ◽  
Tectonic Uplift ◽  
Tectonic Activity ◽  
Tectonic Deformation ◽  
Roughness Effects ◽  
Geomorphic Indices ◽  
River Incision ◽  
Uplift Rates ◽  
Differential Uplift

Uplift is the predominant factor controlling fluvial systems in tectonically deforming regions. Mountains along subduction zones force incision, aggradation, or sinuosity modifications, showing differential uplift and variations in erosion rates, in river incision, and in channel gradient produced by ongoing tectonic deformation. Thus, landscape can provide information on the tectonic activity of a defined region. Here, field studies, analysis of geomorphic indices using a digital elevation model, and dating of river terraces were undertaken to extract the following: (1) determine rates of ongoing tectonic deformation, (2) identify evidence of active faulting, and (3) explain the possible relation of ongoing differential uplift in the topography of the overriding plate with the geometry and roughness effects of subducting slab along the Mexican subduction within the Guerrero sector. Landscape analysis using geomorphic indices suggests segmentation along stream of the studied Tecpan River basin. Rates of tectonic uplift were derived from river incision rates computed with the combination of strath terrace heights and associated dating. Tectonic uplift rates vary from ∼1 ± 0.3 mm/yr up to ∼5 ± 0.6 mm/yr during the Holocene, consistent with inferred high tectonic activity in this zone. These results vary significantly spatially, i.e., increasing upstream. Possible explanations for spatial variations of tectonic uplift rates are most likely related to an effect of the geometry and the rugged seafloor of the oceanic Cocos plate subduction beneath a faulted continental lithosphere.

scholarly journals Quantifying the roles of bedrock damage and microclimate on potential soil production rates, erosion rates, and topographic steepness: A case study of the San Gabriel Mountains, California

2016 ◽  
Author(s):  
Jon D. Pelletier
Keyword(s):  
Empirical Equation ◽  
Landscape Evolution ◽  
Tectonic Uplift ◽  
Production Rates ◽  
San Gabriel Mountains ◽  
Mountain Ranges ◽  
Erosion Rates ◽  
Soil Production ◽  
Uplift Rates

Abstract. Discerning how tectonic uplift rates, climate, soil production rates, erosion rates, and topography interact is essential for understanding the geomorphic evolution of mountain ranges. Perhaps the key independent variable in this interaction is the potential soil production rate, i.e., the upper limit at which bedrock can be converted into transportable material. In this paper I document the controls on potential soil production rates using the San Gabriel Mountains (SGM) of California as a case study. The prevailing conceptual model for the geomorphic evolution of the SGM is that tectonic uplift rates control topographic steepness, erosion rates, and potential soil production rates. I test the alternative hypothesis that bedrock damage and microclimate also exert first-order controls on landscape evolution in the SGM via their influence on potential soil production rates. I develop an empirical equation that relates potential soil production rates in the SGM to a bedrock damage index that depends on the local density of faults and a microclimatic index that relates to aspect-driven variations in vegetation cover and wildfire severity and frequency. Assuming a balance between soil production and erosion rates at the hillslope scale, I further show that observed trends in topographic steepness can be reproduced using the empirical equation for potential soil production rates. The results suggest that tectonic uplift rates, bedrock damage, and microclimate play co-equal and interacting roles in controlling landscape evolution in the SGM and perhaps other tectonically active mountain ranges.

Quaternary Sea Level Fluctuations on a Tectonic coast: New 230Th/234U Dates from the Huon Peninsula, New Guinea

1974 ◽  
Vol 4 (2) ◽  
pp. 185-205 ◽  
Author(s):  
A.L. Bloom ◽  
W.S. Broecker ◽  
J.M.A. Chappell ◽  
R.K. Matthews ◽  
K.J. Mesolella
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
New Guinea ◽  
Tectonic Uplift ◽  
Reef Complex ◽  
Sea Level Fluctuations ◽  
Uplift Rates ◽  
The Mean ◽  
The Difference ◽  
The Individual

Emerged coral reef terraces on the Huon Peninsula in New Guinea were reported in a reconnaissance dating study by Veeh and Chappell 1970. Age definition achieved was not good for several important terraces, and we report here a series of new 230Th/234U dates, which further clarify the history of late Quaternary eustatic sea level fluctuations. More than 20 reef complexes are present, ranging well beyond 250,000 yr old: we are concerned with the seven lowest complexes. Major reef-building episodes dated by 30Th/234U are reef complex I at 5–9 ka (kilo anno = 1000 yr), r.c. IIIb at 41 ka (four dates), r.c. IV at 61 ka (four dates), r.c. V at 85 ka (two dates), r.c. VI at 107 ka (two dates), and r.c. VII at 118–142 ka. Complex II was previously dated by 14C at 29 ka: this age has not yet been confirmed, and may be only a lower limit. The reef crests were built during or immediately before intervals of sea level maxima, when rates of rising sea level and tectonic uplift briefly coincided. The culmination of each reef-building episode was only a few thousand years in duration, and multiple dates from the same reef complex generally group within the statistical errors of the individual dates.Several methods can be used to estimate the altitude of each sea level maximum relative to present sea level. The least complicated is to calculate mean tectonic uplift rate for each profile of the terraces, and use the mean rate to calculate the tectonic displacement of each dated reef complex on that profile. The difference between the present altitude of a reef complex and its calculated tectonic uplift gives the paleosea level at the time the reef grew. We estimate uplift rates for six surveyed sections by calibrating against published paleosea level estimates from Barbados and elsewhere, viz 125 ka, paleosea at +6 m; 103 ka, −15 m; 82 ka, −13 m. For each section the individual uplift rates for reefs V, VI, and VIIb are within 5% of their section means. Using the mean rates. paleosea level estimates for reef crests II, IIIB, and IV are made for each section. Consistency of estimates between sections is good, giving −28 m for the 60 ka paleosea level, around −38 m for the 42 ka level and −41 m for the 28 ka level (if the age is older the paleosea level would be lower. Using the mean uplift rates, the 82 ka and 103 ka paleosea levels are also estimated for each section: all individual estimates are plotted graphically, and a sea level curve drawn. The reef stratigraphy indicates sea level lowerings between each dated reef crest: the crests probably represent the interstadials of the Wisconsin (Würm, Weichsel) Glaciation, and intervening lower levels correspond to stadials. Since the last time of eustatic sea level higher than the present (about 125 ka), five sea level maxima occurred at roughly 20-ka intervals, none being as high as the present.

Electron Microprobe Correlation of Tephra Layers from Eastern Mediterranean Abyssal Sediments and the Island of Santorini

1980 ◽  
Vol 13 (2) ◽  
pp. 160-171 ◽  
Author(s):  
Alan N. Federman ◽  
Steven N. Carey
Keyword(s):  
Major Element ◽  
Late Quaternary ◽  
Eastern Mediterranean ◽  
Explosive Eruptions ◽  
Volcanic Complex ◽  
Quaternary Sediments ◽  
Additional Layer ◽  
Oxygen Isotope Stratigraphy ◽  
Tephra Layers ◽  
Isotope Stratigraphy

AbstractFive widespread tephra layers are found in late Quaternary sediments (0–130,000 yr B.P.) of the Eastern Mediterranean Sea. These layers have been correlated among abyssal cores and to their respective terrestrial sources by electron-probe microanalysis of glass and pumice shards. Major element variations are sufficient to discriminate unambiguously between the five major layers. Oxygen isotope stratigraphy in one of the cores studied was used to data four of the five layers. Two of the widespread layers are derived from explosive eruptions of the Santorini volcanic complex: the Minoan Ash (3370 yr B.P.) and the Acrotiri Ignimbrite (18,000 yr B.P.). An additional layer, found in one core only, is most likely correlated to the Middle Pumice Series of Santorini (approximately 100,000 yr B.P.). Two layers are correlated to deposits on the islands of Yali and Kos and date to 31,000 and 120,000 yr B.P., respectively. One layer originated from the Neapolitan area of Italy 38,000 yr B.P.

Late Quaternary Chronology and Palaeoclimates of the Eastern Mediterranean

1996 ◽  
Vol 23 (4) ◽  
pp. 527
Author(s):  
T. J. Wilkinson ◽  
Ofer Bar-Yosef ◽  
Renee S. Kra
Keyword(s):  
Late Quaternary ◽  
Eastern Mediterranean
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