Evidence of Early Cretaceous remagnetization in the Crimean Peninsula: a palaeomagnetic study from Mesozoic rocks in the Crimean and Western Pontides, conjugate margins of the Western Black Sea

We report on a palaeomagnetic study from Mesozoic sedimentary and volcanic rocks from the conjugate areas of the Western Black Sea Basin; that is, the Crimean Peninsula in the north and the Western and Central Pontides in the south, to better constrain their palaeogeographic relationships within the southern margin of Eurasia. From the study of 87 sites in Crimea, we found that Triassic to Lower Jurassic sandstones and siltstones from the Tavric series, and Middle-Upper Jurassic sandstones, siltstones and limestones exhibit remagnetization. Both fold and conglomerate tests confirm a widespread remagnetization in Crimea. Comparison of palaeopoles with the expected reference apparent polar wander path (APWP) of Eurasia and results from conglomerate tests suggest that the remagnetization occurred in the Early Cretaceous. In the Central Pontides, no reliable palaeomagnetic results can be obtained from Triassic-Upper Jurassic rocks, however, a negative fold test in Upper Jurassic-Lower Cretaceous rocks from the Western Pontides shows that the palaeolatitude agrees with Lower Cretaceous data from Crimea. Our new palaeomagnetic results indicate a pervasive remagnetization in Crimea and the Western Pontides that could be attributed to the rifting phase of the Black Sea Basin during Lower Cretaceou

Curie Point Depths and Heat Flow of Eastern Anatolia (Turkey)

The bottom of the magnetized crust determined from the spectral analysis of magnetic anomalies is generally interpreted as the level of the Curie point isotherm. The spectral analysis method to estimate the depth extent of magnetic sources was applied to the magnetic anomalies of Eastern Anatolia and compared with the tectonic regime and heat flow data in the region. The Curie point depth of eastern Anatolia ranges from 6 to 24 km. The computed Curie depths and the heat flow values derived by using Curie depths are consistent with the geological and the seismological findings of the region. Shallow Curie point depths and high heat flow values are seen between the Bitlis Suture Zone and the pontides. At the same time, this region might contain a thinner crust than expected

Correlation between gravity and magnetic anomalies of Western Anatolia and its relation to tectonic structures

In this paper, we apply for the first time the moving-windows application of the Poisson's theorem to the synthetic gravity and magnetic data, followed by calculations of the correlations of the Bouguer gravity and aeromagnetic data of Western Anatolia. The correlation coefficient, slope and intercept parameters were generated from the internal correlations existing between the gravity and magnetic anomalies. Relative negative correlation values of positive gravity and negative magnetic anomalies were found on the Menderes Massif and in the southern part of the Marmara sea. Higher heat flow values were also obtained from these regions. The negative correlation values can be seen on a profile taken along the 28 E longitude and are sourced from a large graben system which has been generated as a result of lithospheric extension in Western Anatolia since the Early Miocene. The grabens were filled up by approximately 2000-m-thick sediments. The negative correlation coefficients and high heat flow values correspond to relative uplift of the asthenosphere in these regions

Southward migration of arc magmatism during latest Cretaceous associated with slab steepening, East Pontides, N Turkey: New paleomagnetic data from the Amasya region

A new paleomagnetic study was carried out on the Findikli formation in the Amasya region, which is to the north of the Ankara-Erzincan Neotethyan suture zone, in order to better understand the paleogeographic evolution of the Pontides tectonic belt during the Maastrichtian. Samples were collected from volcanoclastic sandstones and lavas at 51 sites. Rock magnetic experiments identified pseudo-single domain (PSD) titanomagnetite as the main magnetic carriers at the majority of sites. Progressive thermal and alternating demagnetization revealed that the characteristic remanent component is removed between 400 and 580 degrees C or 20-100 ml, respectively. A high temperature component, which indicates the presence of titano-hematite, is found only in some lavas. Declinations show a systematic dispersion across the study area related to tectonic rotations about vertical axes. Inclinations are consistent, however, and yield a mean paleolatitude of 20.0 degrees N +/- 2.5 degrees for the Maastrichtian. Comparison of the results from this study with the reference direction of the East Pontides from the Turonian-Campanian is best explained with a model involving slab roll-back and marginal basin formation between 90 and 65 Ma period. (C) 2010 Elsevier B.V. All rights reserved

Evidence of Early Cretaceous remagnetization in the Crimean Peninsula: A palaeomagnetic study from Mesozoic rocks in the Crimean and Western Pontides, conjugate margins of the Western Black Sea

ISSN:0956-540XISSN:1365-246

Thermal structure of the crust in the Black Sea: comparative analysis of magnetic and heat flow data

This paper presents the first study of mapping of the Curie point depth (CPD) from magnetic data for the Black Sea and a comparison with a classical thermal modeling from heat flow data. The provided relationship between radially averaged power spectrum of the magnetic anomalies and the depths to the magnetic sources of the Black Sea vary from 22 to 36 km. Deepening of CPDs observed in the western and eastern Black Sea basins correspond with the thickest sediment areas, whereas the shallow CPDs are related to the Mid-Black Sea Ridge and thin sediment areas at the costal side of the Black Sea. For comparison, the temperature field was also modeled from heat flow data from the Black Sea along three approximately north-south directed profiles corresponding to known DSS soundings. The Curie isotherm along the profiles occurs at depths of 22-35 km. A comparison of the results of the two independent methods reveals only 8-10 % discrepancy. This discrepancy is equal to an accuracy of temperature determination from heat flow data