scholarly journals CONTRIBUTION TO THE LATE NEOGENE STRATIGRAPHY OF THE ANCIENT GORTYS AREA (SOUTHERN CENTRAL CRETE, GREECE)

2017 ◽  
Vol 43 (2) ◽  
pp. 579
Author(s):  
S. Bellas ◽  
H. Keupp
Keyword(s):  
Sedimentary Basin ◽  
Aegean Sea ◽  
Messinian Salinity Crisis ◽  
Extensional Tectonics ◽  
Sedimentary Deposits ◽  
South Central ◽  
Crete Island ◽  
Late Neogene ◽  
Southern Central ◽  
Neogene Sediments

Most of the basal Neogene sediments of Crete Island (South Aegean Sea) were unconformably deposited during synsedimentary extensional tectonics and subsequent transgression on the basement. This work mainly focuses on the marine stratigraphy of south central Crete and specifically on the sedimentary deposits of the Gortys subbasin-area located in the basin of Messara. Four selected profiles north of Gortys ancient ruins (Heraklion Province) are lithostratigraphically presented. Profiles Gortys-1 and -2 (combined to one: 1+2) represent the basal Neogene deposits (older strata-commence of sedimentation) and are interpreted as of fluviatile to lagoonal origin, while profiles Gortys-4 and - 4a are considered the younger, marine development of the Gortys subbasin. Between profiles –4 and –4a are developed evaporites of the Messinian Salinity Crisis (MSC). Profiles are biostratigraphically studied and correlated on the basis of either identified macrofossils or calcareous and siliceous nannofossils. The recorded assemblages range in age from Serravallian-Tortonian to Messinian and Zanclean respectively. The good preservation and abundance of the fossil phytoplankton establishes a well-constrained biostratigraphic framework, which will further contribute to the understanding of the evolution of the Messara sedimentary basin.

scholarly journals Subsurface Geological Characterization of the Late Neogene–Quaternary Argive Basin, Peloponnese, Greece Using Transient Electromagnetic Data and Vintage Stratigraphic Logs

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 317
Author(s):  
Hector R. Hinojosa-Prieto ◽  
Pantelis Soupios ◽  
Pavel Barsukov
Keyword(s):  
Electrical Resistivity ◽  
Sedimentary Basin ◽  
Aegean Sea ◽  
Tectonic Structures ◽  
Transient Electromagnetic ◽  
Geophysical Surveys ◽  
Late Neogene ◽  
Half Graben ◽  
Joint Interpretation ◽  
Surface Geology

The onshore and offshore clastic deposits of the Argive Basin and the Argolic Gulf, respectively, in Peloponnese, Greece, form a Late Neogene–Quaternary half-graben that connects with the Aegean Sea. The onshore Late Neogene–Quaternary sequence, comprised of chaotically intercalated cohesive and granular clastic deposits, is in angular unconformity with bedrock comprised of Triassic–Upper Cretaceous strongly-weathered, highly-fractured karstic limestones thrusted against Paleogene flysch deposits. While the surface geology of the Argive Basin is well-known, the subsurface geology remains both poorly mapped and understood. We utilized transient electromagnetic (TEM) soundings coupled with 185 vintage stratigraphic logs, current surface geology knowledge, and insights from available geophysical surveys to characterize the subsurface conditions of this sedimentary basin. We estimated the thickness of the young deposits (the depth to bedrock) and detected potential subsurface tectonic structures. The TEM-FAST 48HPC data acquisition system with integrated inversion and visualization software package was used with a single-loop dimension of 50 m × 50 m to collect a total of 329 TEM soundings at 151 stations scattered throughout the basin. The TEM station spacing varied from 200 to 750 m allowing the mapping of 80 km2. The total depth of investigation with the inverted TEM data and the lithology logs was 130 m and 183 m, respectively. The joint interpretation produced several quasi-two-dimensional electrical resistivity profiles that traverse the sedimentary basin in various azimuths and depth slices of average electrical resistivity covering the basin. The depth slices and the vintage stratigraphic logs revealed an uneven bedrock topography overlain by an irregularly thick (over 180 m) Late Neogene–Quaternary heterolithic sediment cover.

scholarly journals A giant termite of the genus Gyatermes from the late Miocene of Nagano Prefecture, Japan (Isoptera)

2015 ◽  
pp. 1
Author(s):  
Michael S. Engel ◽  
Toshiaki Tanaka
Keyword(s):  
New Species ◽  
Late Miocene ◽  
Central Japan ◽  
Nagano Prefecture ◽  
Late Neogene ◽  
Neogene Sediments ◽  
A New Species

A new species of the termite genus <em>Gyatermes</em> Engel &amp; Gross (Archotermopsidae) is described and figured from a beautifully preserved forewing in late Neogene sediments of Nagano Prefecture, central Japan.  The approximately 27-mm long forewing of <em><strong>Gyatermes naganoensis</strong></em> Engel &amp; Tanaka, new species, is preserved in Late Miocene (late Messinian) mudstone of the Ogawa Formation (<em>ca</em>. 6 Ma), and is distinguished from its slightly older and larger congener <em>G. styriensis</em> Engel &amp; Gross, from the early Tortonian of Styria, Austria.  Comments are provided regarding the paleoclimatic implications of a giant termite in the Miocene fauna of Nagano.

A scale-independent model for land-locked seas with application to the Messinian salinity crisis

2020 ◽  
Author(s):  
Paul Meijer
Keyword(s):  
Mediterranean Sea ◽  
Independent Solution ◽  
Aegean Sea ◽  
Basic Element ◽  
Messinian Salinity Crisis ◽  
Elevated Salinity ◽  
Levantine Basin ◽  
The Mediterranean ◽  
Atmospheric Heat

&lt;p&gt;While the Mediterranean Sea is, since the Middle Miocene, a nearly completely land-locked basin indeed, it is itself comprised of several smaller semi-enclosed seas. What the Mediterranean Sea as a whole is to the Atlantic Ocean, are the Adriatic Sea or Aegean Sea to the Ionian-Levantine basin, for example. In the discussions regarding the Messinian salinity crisis the marginal basins of the Mediterranean play a prominent role because it is from these parts that the sedimentary record has been uplifted and become exposed.&lt;/p&gt;&lt;p&gt;In view of this and with an aim to contribute insight from the field of modelling, we focus on the basic element: a single marginal basin, subject to atmospheric forcing and exchanging water through a seaway with an adjacent larger basin. The equations are derived in dimensionless form and a universal, scale-independent, solution for basin salinity obtained. The analysis yields two dimensionless ratios which control basin behaviour in terms of salinity and response time.&amp;#160;&lt;/p&gt;&lt;p&gt;Application of the theoretical model to the Messinian salinity crisis sheds new light on the formation of gypsum in marginal basins that were separated from the main Mediterranean by a sill, gives insight about the role of atmospheric heat exchange, and underlines the previous finding that, at elevated salinity, marginal basins respond to periodic climate variation (e.g. due to precession) with a significant lag.&lt;/p&gt;

The Aegean Sea

1981 ◽  
Vol 300 (1454) ◽  
pp. 357-372 ◽  
Keyword(s):  
Quantitative Estimate ◽  
Kinematic Model ◽  
Aegean Sea ◽  
Continental Collision ◽  
Formation Processes ◽  
Extensional Tectonics ◽  
Aegean Area ◽  
Vertical Movements ◽  
Hellenic Arc ◽  
Marginal Sea

We summarize briefly the main features of a kinematic model of evolution of the Aegean area since 13 Ma. The formation of the Aegean Sea by extensional tectonics is related to the subduction of the Mediterranean floor below the Hellenic arc. We then make a quantitative estimate of vertical movements in the Aegean area, on the basis of geological data, and demonstrate that the outer arc was built since the beginning of this episode of subduction by vertical uplift. The easiest way to explain the uplift is by underplating. Finally, we discuss briefly the dynamics of the subduction - marginal sea formation processes in this continental collision framework.

scholarly journals The Hellenic Seismological Network of Crete (HSNC): validation and results of the 2013 aftershock sequences

2016 ◽  
Vol 41 ◽  
pp. 65-72 ◽  
Author(s):  
G. Chatzopoulos ◽  
I. Papadopoulos ◽  
F. Vallianatos
Keyword(s):  
Eastern Mediterranean ◽  
Tall Buildings ◽  
Aegean Sea ◽  
Regional Seismicity ◽  
Small Areas ◽  
Crete Island ◽  
Main Shocks ◽  
Aftershock Sequences ◽  
Seismological Network

Abstract. The last century, the global urbanization has leaded the majority of population to move into big, metropolitan areas. Small areas on the Earth's surface are being built with tall buildings in areas close to seismogenic zones. Such an area of great importance is the Hellenic arc in Greece. Among the regions with high seismicity is Crete, located on the subduction zone of the Eastern Mediterranean plate underneath the Aegean plate. The Hellenic Seismological Network of Crete (HSNC) has been built to cover the need on continuous monitoring of the regional seismicity in the vicinity of the South Aegean Sea and Crete Island. In the present work, with the use of Z-map software the spatial variability of Magnitude of Completeness (Mc) is calculated from HSNC's manual analysis catalogue of events from the beginning of 2008 till the end of September 2015, supporting the good coverage of HSNC in the area surrounding Crete Island. Furthermore, we discuss the 2013 seismicity when two large earthquakes occurred in the vicinity of Crete Island. The two main shocks and their aftershock sequences have been relocated with the use of HYPOINVERSE earthquake location software. Finally, the quality of seismological stations is addressed using the standard PQLX software.

scholarly journals NEW SIRENIAN FINDINGS FROM CRETE ISLAND

2017 ◽  
Vol 43 (2) ◽  
pp. 746
Author(s):  
K. Svana ◽  
G. Iliopoulos ◽  
C. Fassoulas
Keyword(s):  
Late Miocene ◽  
Coastal Areas ◽  
Marine Environments ◽  
Crete Island ◽  
New Localities ◽  
Neogene Sediments

In the last five years, the discovery of several new localities of fossil Sirenians found in the Neogene sediments of Crete has increased drastically the number of sirenian localities on the island. Some of the most important findings consist of almost complete post cranial skeletons (localities of Stilos, Panassos near Zaros and Tripitos in Agia Fotia near Siteia). Furthermore, the locality Kotsiana near Chania, where in 1973 Symeonidis and Schultz reported the first sirenian findings from Crete, was revisited and several new sites were recorded. The most recent findings not thoroughly studied yet, are situated in three new fossiliferous sites near Panassos village (Ampelouzos, Panasos 2 and Kefala), and in Afrata at Rodopou peninsula. The preliminary morphological and metrical study of the remains from Panassos and Tripitos, and their comparison with other findings from Crete, as well as with Sirenian material from European localities, has shown that all studied individuals belong to the species Metaxytherium cf. medium (Desmarest 1822). The age of the studied Cretan Sirenian material has been determined as Late Miocene (Tortonian) and the presence of Sirenia in Crete indicates the prevalence of shallow and warm marine environments in coastal areas, rich in sea weeds.

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