South-central Crete Research Articles

How have Cretan rivers responded to late Holocene uplift? A multi‐millennial, multi‐catchment field experiment to evaluate the applicability of Schumm and Parker's (1973) complex response model

Abstract‘Complex response’ (Schumm, 1973, Geomorphic thresholds and complex response of drainage systems. In Morisawa, M. (ed.), Fluvial Geomorphology. Binghamton: New York State University Publications: 299‐310) describes situations in which a single event triggers a series of progressively damped morphological and sedimentary adjustments within a catchment. Schumm and Parker's (1973, Implications of complex response of drainage systems for Quaternary alluvial stratigraphy. Nature 243: 99–100) classic stream table experiment of drainage system development showed that one baselevel fall event could result in formation of two sets of paired river terraces that need not be related to additional external (e.g., climate) influences. Despite its enduring popularity in fluvial geomorphology, large‐scale and long‐term field evaluations of Schumm and Parker's complex response model are very limited. Here, we report on a multi‐millennial, multi‐catchment field experiment in south‐western Crete where a high‐magnitude earthquake (estimated magnitude 8.3–8.5) on 21 July 365 ce resulted in up to 9 m of instantaneous uplift over a land area exceeding 6000 km2. Geomorphological, sedimentological, and chronological investigations were used to investigate the erosional and depositional histories in three catchments with outlets uplifted by the 365 ce event. These catchments were compared with the Anapodaris catchment in south central Crete where baselevel was not significantly affected by the earthquake. Although all uplifted catchments experienced valley floor incision, this occurred hundreds of years after 365 ce during a period of wetter climate. The number and age of trunk stream incision and aggradation phases are similar in both uplifted and non‐uplifted catchments, indicating that river responses following the 365 ce uplift event have not followed complex response trajectories in the form documented by Schumm and Parker (1973). This finding highlights the need for rigorous evaluation of other catchment or river response concepts, including through the combined use of laboratory experimental results, field data, and geochronology. In an era of rapid environmental change, characterizing and anticipating catchment and river system response increasingly will depend on a healthy interplay between different investigative approaches.

Materials analyses of stone artifacts from the EBA to MBA Minoan Tholos tomb P at Porti, Greece (Crete), by means of Raman spectroscopy: Results and a critical assessment of the method

Detailed analytical work based on mobile Raman microspectroscopy has been performed on a mortuary assemblage, comprising a group of 59 stone artifacts (vessels, implements and figurines) excavated in one of the richest burial sites in south-central Crete, Tholos tomb P at the Minoan site of Porti (ca. 2700–1700 BCE). Mineral identification was possible for over half of the objects examined and the results expand our understanding, originally obtained on the basis of visual and microscopic characterization of the objects. Patterns of variability in the stones investigated are correlated with the typological repertoire of the final products and compared with data from the neighboring site of Apesokari; further inferences on craft specialization issues are finally drawn. In all, the data obtained lead us to suggest that stone vessel manufacture at Porti was predominantly focused on the exploitation of local softstone outcrops. This hypothesis agrees with the current knowledge concerning the geological formation of the Asterousia area, on the northern fringes of which the site of Porti is located. In parallel, the capacity of mobile Raman microspectrometry to contribute to stone object characterization as regards their mineral composition is discussed along with advantages and limitations of the methodology followed. Raman analysis is preformed quickly, non-invasively, directly on the object and over several spots across its surface for probing heterogeneous mineral distributions. The mobile spectrometer permits measurements to be conducted on location, namely within the museum study facilities. A major limitation with respect to obtaining clean analytical information resulted from strong fluorescence emission observed in some of the measurements, which interfered with the Raman scattering signal. These emissions were attributed to organic materials present on the stone surface either as environmental contamination or as a result of previous, often undocumented, conservation treatments. Finally, the need to collect and thoroughly characterize local stone outcrops as well as archaeological stone objects has become evident and building a representative Raman spectral database will certainly facilitate future studies.

Temporally Constant Quaternary Uplift Rates and Their Relationship With Extensional Upper‐Plate Faults in South Crete (Greece), Constrained With36Cl Cosmogenic Exposure Dating

AbstractPreserved sets of marine terraces and palaeoshorelines above subduction zones provide an opportunity to explore the long‐term deformation that occurs as a result of upper‐plate extension. We investigate uplifted palaeoshorelines along the South Central Crete Fault and over its western tip, located above the Hellenic Subduction Zone, in order to derive uplift rates and examine the role that known extensional faults contribute to observed coastal uplift. We have mapped palaeoshorelines and successfully dated four Late‐Quaternary wave‐cut platforms using in situ36Cl exposure dating. These absolute ages are used to guide a correlation of palaeoshorelines with Quaternary sea level highstands from 76.5 to ~900 ka; the results of which suggest that uplift rates vary along fault strikes but have been constant for up to 600 ka in places. Correlation of palaeoshorelines across the South Central Crete Fault results in a throw‐rate of 0.41 mm/year and, assuming repetition of 1.1‐m slip events, a fault‐specific earthquake recurrence interval of approximately 2,700 years. Elastic‐half‐space modeling implies that coastal uplift is related to offshore upper‐plate extensional faults. These faults may be responsible for perturbing the uplift rate signals in the south central Crete area. Our findings suggest that where uplifted marine terraces are used to make inferences about the mechanisms responsible for uplift throughout the Hellenic Subduction Zone, and other subduction zones worldwide, the impact of upper‐plate extensional faults over multiple seismic cycles should also be considered.

Patterns of Visibility, Intervisibility and Invisibility at Bronze Age Apesokari (Crete)

AbstractTholos A at Apesokari (south-central Crete, Greece) was constructed on a sloping ledge of bedrock, overlooking the Mesara Plain below. Such an inconvenient topographic setting makes Tholos A an unusual example in the corpus of Minoan circular tombs, which were more commonly built on flatter ground. The builders seem to have cared greatly about placing Tholos A precisely at this location, even at the risk of jeopardizing the stability of its circular chamber. Furthermore, due to limited space availability, the annex rooms of Tholos A had to be built at a higher level on the bedrock, resulting in an architectural configuration unparalleled in other circular tombs. This paper addresses the question of why this particular location was chosen for the construction of Tholos A. Geographical Information Systems (GIS) are used to examine the possibility that concerns related to visibility, intervisibility or invisibility may have played a role in the decision to build Tholos A at this particular spot. Five potential scenarios are formulated and tested to assess whether the tomb may have been placed with the intention of maximizing its visibility and ensuring (or, to the contrary, preventing) intervisibility with specific features in the local landscape.

First evidence of a lake at Ancient Phaistos (Messara Plain, South-Central Crete, Greece): Reconstructing paleoenvironments and differentiating the roles of human land-use and paleoclimate from Minoan to Roman times

Phaistos was one of the most important Minoan palaces in Crete and previous studies have addressed its relationship with the paleo-seashore position during historical times. Here, we reconstruct the environmental evolution of Phaistos from Early Minoan to Roman times. Study of two stratigraphic sections and nine boreholes drilled in the westernmost part of the Messara Plain has revealed the stratigraphy of the Mid- to Late-Holocene sediments. Laboratory analyses comprise granulometry, magnetic susceptibility measurements and identification of mollusks, diatoms and pollen grains. Eighteen radiocarbon dates provide a robust chronostratigraphy. In addition, a geophysical survey (electric resistivity tomography (ERT) method) was conducted to reveal the sub-surface morphology in the coring area. The results reveal that a freshwater lake existed from ca. 2100–2000 BC to ca. 1200–1100 BC, which subsequently became swampland until ca. 700 BC. A lake retreat is identified at ca. 1200–1000 BC and can be interpreted as resulting from the 3.2 cal kyr BP rapid climate change (RCC) dry event, observed elsewhere in the Eastern Mediterranean. Subsequently, from the 7th to the 5th century BC, there was the input of detrital material and fluvial dynamics prevailed until at least Roman times. The origin of the lake and its disappearance are discussed in the context of regional climate change and local tectonic activity, without excluding possible human influences. We also reconstruct the vegetation history for the period from the Late Minoan to the Early Archaic period. Pollen analysis reveals a Mediterranean maquis landscape dominated by Olea, together with hygrophilous vegetation, and highlights a clear transition from limnic to swampy environmental conditions around 1100 BC. The pollen sequence is also important for assessing the impact of the 3.2 cal. kyr BP RCC event and for assessing the possibility of an abrupt discontinuity in human activity around Phaistos after the demise of the Minoan Civilization.

Reconstructing change in firing technology during the Final Neolithic\u2013Early Bronze Age transition in Phaistos, Crete. Just the tip of the iceberg?

Changes in firing practice have been suggested as representing a revolution in ceramic technology at the beginning of the Bronze Age in Crete. The introduction of kiln structures has been held responsible for such a change, perhaps by newcomers to the island, along with other innovative technologies. However, these hypotheses were often based on limited analytical data and mostly on macroscopic examination. This paper re-examines the suggestion of a transformation in firing technology at the beginning of the Bronze Age by presenting analyses of the rich ceramic assemblage from the site of Phaistos in South-Central Crete, which offers a rare, good stratigraphic sequence from the end of the Final Neolithic into the Early Bronze Age. Here, firing technology is reconstructed by macroscopic examination of colour across vessel breaks, by SEM examination and FT-IR analysis. This allows the reconstruction of temperature ranges and firing rates over the phases considered and a re-assessment of changes in firing technology, revealing a more multi-faceted pattern of change. Finally, changes in firing procedure are contextualised in the overall ceramic operational sequence, revealing a complex, stepped picture of change in ceramic production over the transition from the Final Neolithic.

River profile response to normal fault growth and linkage: an example from the Hellenic forearc of south-central Crete, Greece

Abstract. Topography is a reflection of the tectonic and geodynamic processes that act to uplift the Earth's surface and the erosional processes that work to return it to base level. Numerous studies have shown that topography is a sensitive recorder of tectonic signals. A quasi-physical understanding of the relationship between river incision and rock uplift has made the analysis of fluvial topography a popular technique for deciphering relative, and some argue absolute, histories of rock uplift. Here we present results from a study of the fluvial topography from south-central Crete, demonstrating that river longitudinal profiles indeed record the relative history of uplift, but several other processes make it difficult to recover quantitative uplift histories. Prior research demonstrates that the south-central coastline of Crete is bound by a large ( ∼ 100 km long) E–W striking composite normal fault system. Marine terraces reveal that it is uplifting between 0.1 and 1.0 mm yr−1. These studies suggest that two normal fault systems, the offshore Ptolemy and onshore South-Central Crete faults, linked together in the recent geologic past (ca. 0.4–1 My BP). Fault mechanics predict that when adjacent faults link into a single fault the uplift rate in footwalls of the linkage zone will increase rapidly. We use this natural experiment to assess the response of river profiles to a temporal jump in uplift rate and to assess the applicability of the stream power incision model to this setting. Using river profile analysis we show that rivers in south-central Crete record the relative uplift history of fault growth and linkage as theory predicts that they should. Calibration of the commonly used stream power incision model shows that the slope exponent, n, is ∼ 0.5, contrary to most studies that find n ≥ 1. Analysis of fluvial knickpoints shows that migration distances are not proportional to upstream contributing drainage area, as predicted by the stream power incision model. Maps of the transformed stream distance variable, χ, indicate that drainage basin instability, drainage divide migration, and river capture events complicate river profile analysis in south-central Crete. Waterfalls are observed in southern Crete and appear to operate under less efficient and different incision mechanics than assumed by the stream power incision model. Drainage area exchange and waterfall formation are argued to obscure linkages between empirically derived metrics and quasi-physical descriptions of river incision, making it difficult to quantitatively interpret rock uplift histories from river profiles in this setting. Karst hydrology, break down of assumed drainage area discharge scaling, and chemical weathering might also contribute to the failure of the stream power incision model to adequately predict the behavior of the fluvial system in south-central Crete.

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

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.

Communication Networks, Interactions, and Social Negotiation in Prepalatial South-Central Crete

Circular tombs are our best source of information regarding life and death in Prepalatial south-central Crete (3100-1900 BC). This article aims at tackling the phenomenon of movement in that particular area to shed new light on interactions among the communities that constructed and used such tombs. It employs Geographical Information Systems (GIS) and builds on the recently developed focal mobility network procedure to get insights into patterns of movement in south-central Crete. The results of the GIS analyses emphasize that circular tombs were as a rule constructed in close proximity to optimal paths. Nevertheless, the spatial pattern testifies to synchronic and diachronic variations, which, examined in the light of the distribution of non-Cretan grave goods, support the conclusion of previous research that different social strategies underlay the appearance and adoption of the particular burial type throughout the study area. Even though the wide distribution of circular tombs across south-central Crete points to shared cultural values, the process of diffusion was clearly far from homogeneous.

Assessing soil salinity using WorldView-2 multispectral images in Timpaki, Crete, Greece

Salinization is one of the major soil degradation threats occurring worldwide. This study evaluates the feasibility of operational surface soil salinity mapping based on state-of-the-art Earth Observation (EO) products captured by sensors on-board WorldView-2 (WV2) and Landsat 8 satellites. The proposed methods are tested in Timpaki, south-central Crete,Greece, where brackish water irrigation puts soil health at risk of soil salinization. In all cases, EO products are calibrated against soil samples collected from bare soil locations. Results indicate a moderate correlation of observed ECe values with the investigated remote sensing parameters. Regarding sensitivity to saline soil, the yellow band displays higher values. Comparison between methods used in the literature shows that those developed specifically for soil salinity, and especially index S5, perform better. The proposed ‘detection index’ and 3D PCA transformation methodology perform reasonably well in detecting areas with high ECe values and provide a simple and effective operational alternative for saline topsoil detection and mapping.

THE PROBLEM WITH CLAUDIUS: SOME REVISIONS IN CERAMIC CHRONOLOGY IN CENTRAL CRETE DURING THE JULIO-CLAUDIAN PERIOD

This article may seem to some to be unnecessarily precise in the dating of later Claudian and Neronian ceramic assemblages at Knossos. The aim is to address the fact that various scholars have dated their material to the reign of Claudius, when one can proffer a counterargument that we should place the assemblages in question in the time of Nero. In short, the period under discussion barely covers ad 50–60, and it may seem impossible to attempt a closer chronology without the aid of numismatic evidence. Nevertheless, if related material from south-central Crete is to be securely anchored, such a study must be undertaken.Five Knossian deposits and two from elsewhere in Crete, usually dated to about the middle of the first century ad, are treated here and are assigned to the reign of Nero. It is to be hoped that such a revision will bring the archaeological evidence from north and south-central Crete into better agreement, and it may even be of use to scholars working elsewhere in the Roman world.

Modeling Soil Salinity in Greenhouse Cultivations Under a Changing Climate With SALTMED

Soil salinity is a major soil degradation threat especially for arid coastal environments where it hinders agricultural production, thus imposing a desertification risk. In the prospect of a changing climate, soil salinity caused by brackish water irrigation introduces additional uncertainties regarding the viability of deficit irrigation and intensive cultivation practices such as greenhouse cropping. Here, we propose a modification of the SALTMED leaching requirement model to account for greenhouse cultivation conditions. The model is applied in the RECARE Project Case Study of Timpaki, a semiarid region in south-central Crete, Greece, where greenhouse horticulture is an important land use. Excessive groundwater abstractions toward irrigation have resulted in a drop of the groundwater level in the coastal part of the aquifer, thus leading to seawater intrusion and in turn to soil salinization. Crop yield and soil profile electrical conductivity (EC) sensitivity to initial soil EC (up to 2 dS m−1) and irrigation water EC (up to 3 dS m−1) are modeled for the locally popular horticultural crops of Solanum lycopersicum, Solanum melongena, and Capsicum annuum. Climate model data obtained from nine general circulation models for the “worst case” representative concentration pathway of 8.5 W m−2 of the fifth phase of the Coupled Model Intercomparison Project are corrected for bias against historical observations with the Multisegment Statistical Bias Correction method and used to estimate crop yield and soil profile EC sensitivity in a warmer future. Results show that the effects of climate change on S. lycopersicum greenhouse cultivations of Timpaki will be detrimental, whereas S. melongena and C. annuum cultivations may show greater resilience.

Evolving settlement patterns, spatial interaction and the socio-political organisation of late Prepalatial south-central Crete

Simulations of spatial interaction in archaeology have been successful in predicting the emergence of central sites, and political and economic hierarchies that match observed long-term settlement patterns. It still remains unclear, however, to what degree such models can effectively allow for uncertainty in the archaeological record, especially when it comes to incomplete and unevenly distributed settlement data, and how best they might incorporate artefact-scale evidence. This paper aims to address these issues, while attempting to tackle widely debated aspects of socio-political organisation and cultural interaction in the prehistoric Cretan landscape at the period immediately before and after the foundation of the first palace of Phaistos, one of the less well documented Bronze Age phases. We employ a simulation of spatial interaction inspired by approaches first developed in urban geography and combine this with regression-based predictive modelling to address the uncertainty introduced by missing settlements. We use evidence from artefact analysis partly to calibrate and partly to validate our model. We conclude that such an approach can contribute to more convincing archaeological theories about socio-political organisation, cultural affinity and regional identity by providing new evidence even in the presence of very fragmented data.

Evaluation of promising technologies for soil salinity amelioration in Timpaki (Crete): a participatory approach

Abstract. Soil salinity management can be complex, expensive, and time demanding, especially in arid and semi-arid regions. Besides taking no action, possible management strategies include amelioration and adaptation measures. Here we apply the World Overview of Conservation Approaches and Technologies (WOCAT) framework for the systematic analysis and evaluation and selection of soil salinisation amelioration technologies in close collaboration with stakeholders. The participatory approach is applied in the RECARE (Preventing and Remediating degradation of soils in Europe through Land Care) project case study of Timpaki, a semi-arid region in south-central Crete (Greece) where the main land use is horticulture in greenhouses irrigated by groundwater. Excessive groundwater abstractions have resulted in a drop of the groundwater level in the coastal part of the aquifer, thus leading to seawater intrusion and in turn to soil salinisation. The documented technologies are evaluated for their impacts on ecosystem services, cost, and input requirements using a participatory approach and field evaluations. Results show that technologies which promote maintaining existing crop types while enhancing productivity and decreasing soil salinity are preferred by the stakeholders. The evaluation concludes that rainwater harvesting is the optimal solution for direct soil salinity mitigation, as it addresses a wider range of ecosystem and human well-being benefits. Nevertheless, this merit is offset by poor financial motivation making agronomic measures more attractive to users.

Active simultaneous uplift and margin-normal extension in a forearc high, Crete, Greece

The island of Crete occupies a forearc high in the central Hellenic subduction zone and is characterized by sustained exhumation, surface uplift and extension. The processes governing orogenesis and topographic development here remain poorly understood. Dramatic topographic relief (2–6 km) astride the southern coastline of Crete is associated with large margin-parallel faults responsible for deep bathymetric depressions known as the Hellenic troughs. These structures have been interpreted as both active and inactive with either contractional, strike-slip, or extensional movement histories. Distinguishing between these different structural styles and kinematic histories here allows us to explore more general models for improving our global understanding of the tectonic and geodynamic processes of syn-convergent extension. We present new observations from the south–central coastline of Crete that clarifies the role of these faults in the late Cenozoic evolution of the central Hellenic margin and the processes controlling Quaternary surface uplift. Pleistocene marine terraces are used in conjunction with optically stimulated luminesce dating and correlation to the Quaternary eustatic curve to document coastal uplift and identify active faults. Two south-dipping normal faults are observed, which extend offshore, offset these marine terrace deposits and indicate active N–S (margin-normal) extension. Further, marine terraces preserved in the footwall and hanging wall of both faults demonstrate that regional net uplift of Crete is occurring despite active extension. Field mapping and geometric reconstructions of an active onshore normal fault reveal that the subaqueous range-front fault of south–central Crete is synthetic to the south-dipping normal faults on shore. These findings are inconsistent with models of active horizontal shortening in the upper crust of the Hellenic forearc. Rather, they are consistent with topographic growth of the forearc in a viscous orogenic wedge, where crustal thickening and uplift are a result of basal underplating of material that is accompanied by extension in the upper portions of the wedge. Within this framework a new conceptual model is presented for the late Cenozoic vertical tectonics of the Hellenic forearc.

Transport Stirrup Jars from the Southern Levant: New Light on Commodity Exchange in the Eastern Mediterranean

This article examines the issue of the distribution of transport stirrup jars found in the Late Bronze Age Levant. These vessels, representing long-range commodity exchange, are presumed to be largely of Cretan origin according to both their appearance and previous archaeometric analyses. However, determining whether non-Minoan sources of such vessels exist and identifying specific locales of production within Crete are ongoing foci of research. In this context, a group of transport stirrup jars from Late Bronze Age sites in Israel, predominantly from the harbor site of Tell Abu Hawam, was subjected to thin-section petrographic analysis. This group includes most of the examples known from this region. The results of the analysis indicate that a large proportion of the vessels, especially those found at Tell Abu Hawam, were produced in central or south-central Crete, although other Cretan and possibly non-Cretan sources also occur. A striking mirroring of this situation occurs on Crete at Kommos, a site exceptionally rich in ceramic imports of all kinds, including Canaanite amphoras produced in the vicinity of Tell Abu Hawam. Possible links between these two sites are discussed, shedding new and interesting light on the nature of bulk commodity exchange in the eastern Mediterranean during the Late Bronze Age. *

Holocene flooding and river development in a Mediterranean steepland catchment: The Anapodaris Gorge, south central Crete, Greece

Many Mediterranean steepland rivers are flanked by extensive alluvial and colluvial deposits, but Late Quaternary histories of channel and hillslope behaviour remain poorly constrained, primarily because of the limited availability of material suitable for dating. Study of a 4.8 km long reach of the Anapodaris Gorge, located in the lower part of an ∼ 500 km 2 catchment in south central Crete, reveals a succession of well preserved, coarse-grained (predominantly cobble to boulder) and fine-grained (predominantly silt to sand) alluvial deposits that locally interfinger with, or are overlain by, coarse colluvial and tributary stream deposits. Detailed ground surveys, geomorphological mapping, sedimentological investigations, and geochronology (optically stimulated luminescence, radiocarbon, and lichenometry) have allowed detailed reconstruction of the timing and pattern of sedimentation and erosion over the mid to late Holocene. Widespread, coarse-grained aggradational episodes at c. 4.86–4.20 and c. 3.40–3.00 ka have been punctuated by incisional episodes and coarse sediment export, resulting in a suite of alluvial terraces. Comparison with other proxy Mediterranean environmental change records, particularly high-resolution marine and lake records, suggests that these aggradational/incisional episodes were primarily climatically driven, reflecting changes in the balance between hillslope/tributary sediment supply and high-energy flood events. By contrast, phases of widespread fine-grained aggradation at c. 1.90 ka, 1.13 to 1.10 ka, 0.85 to 0.70 ka and 0.21 ka provide evidence for decreases in flood competence, possibly coupled with up-catchment historical land use changes. Since the middle of the nineteenth century, several large floods have formed localised boulder berms and splays and have contributed to stripping of the fine-grained deposits from many parts of the gorge. The findings from the Anapodaris Gorge demonstrate the sensitivity of Mediterranean steepland catchments to rapid and/or short-lived Holocene climate change but also highlight the need for higher resolution data on historical and prehistoric land use changes.

First record of the invasive miteTetranychus evansi in Greece

The red spider miteTetranychus evansi (Acari: Tetranychidae) Baker and Pritchard was recorded for the first time in Greece, in the area of Tympaki (south-central Crete) onSolanum nigrum. T. evansi is a pest of crops of the family Solanaceae, which are grown extensively in Crete. The species identification was based on both morphological and molecular data. The second internal transcribed spacer was PCR amplified and sequenced in samples from Crete. Sequences were compared with the sequence ofT. evansi from Brazil and with the ITS2 sequences (retrieved from GenBank) of the two closely related tetranychid species most commonly found in Greece,Tetranychus turkestan andTetranychus urticae.

Architecture and Late Pliocene to recent evolution of outer-arc basins of the Hellenic subduction zone (south-central Crete, Greece)

Abstract The Island of Crete is situated in the subaerially exposed part of the Hellenic fore-arc and was uplifted up to 1000–2000 m during Middle Pliocene to recent time. The onset of the overall emergence and northward tilting of central Crete was accompanied by the deposition of the continental Agia Galini Formation ( AGF ) during early Late Pliocene to Early Pleistocene time. The basin evolution during that time was probably related to sinistral wrench tectonics along ENE–WSW faults, which might have been active during an early stage of the incipient collision of the Hellenic fore-arc with the edge of the African continental plate at the longitude of western Crete. The development of the pronounced relief of south-central Crete strongly profits from a second stage of accelerated uplift and differential block movement starting not earlier than Early Pleistocene time or even later (post-AGF). Synchronously, the modern Timbaki basin and the extensive Messara basin (Messara plain) became striking elements in the study area. Across the study area, differences in both the morphostructural features and the amount of extension are obvious from the west to the east. Most likely, they reflect regional differences in the Pleistocene subduction process, due to the incipient continental collision at the longitude of western Crete. In the western part of the study area, arc-normal extension is driven primarily by the accumulation of high gravitational potential energy that results from the rapid uplift of the region. In the eastern part, the NW–SE to NNW–SSE regional extensional stress field is induced by the ongoing subduction of the oceanic African plate and the roll-back resulting in an arc-normal extensional component, and the extrusion of the Anatolian plate. The latter and the lengthening of the Hellenic arc, which is caused by the southward migration of the central part of the arc, support an arc-parallel extensional component. The Psiloritis Southern Escarpment Fault ( PSEF ) is one of the most prominent faults in the study area and represents the near-surface expression of a major normal detachment fault. Based on the footwall uplift mechanism vertical displacement along the PSEF intensifies the considerable asymmetric uplift of the Psiloritis massif that was induced by the regional rise of the outer-arc. In the study area a large number of faults have been identified that give clear evidence of recent activity.

Incipient continental collision and plate-boundary curvature: Late Pliocene–Holocene transtensional Hellenic forearc, Crete, Greece

Geodynamic controls on Late Pliocene–Holocene kinematics of the Hellenic forearc are assessed using the fan–deltaic basin fill of the Messaras forearc basin of south–central Crete. Previously unrecognized 070° sinistral faults developed in wrench-dominated transtension with strike-slip:normal-slip ratios of 10:1 to 100:1. Coeval folds developed in proximity to the 070° sinistral faults during deposition of the Galini Formation, making them candidates to have developed in transtension, and new chronostratigraphic and 87 Sr/ 86 Sr data constrain the age of initial sinistral transtension and associated folding to c . 3.4 Ma. Sinistral fault activity continued through Late Holocene time based on the ages of displaced units with implications for seismic hazards in central Crete. The Messaras structural assemblages are symptomatic of the regional-scale Hellenic forearc with Plio-Pleistocene basins both offshore and onshore Crete controlled by sinistrally dominated 070° faults and secondary 020° extensional oversteps. Although the post-Miocene plate-convergence vectors became increasingly oblique, deformation in transtension, not transpression, has driven Hellenic forearc kinematics. Incipient collision with an African promontory blocked further outward expansion of the Aegean plate boundary along western Crete but induced forearc slivers to be displaced northeastward and sheared sinistrally off the free expanding edge of Aegea as the Cretan–Rhodes forearc was simultaneously stretched. Such a kinematic regime has probably operated since c . 3.4 Ma when the Messaras 070° wrench-dominated system became active and represents tectonic escape during incipient continental collision.