Georgios Christofides | Aristotle University of Thessaloniki (original) (raw)
Papers by Georgios Christofides
Geologica Balcanica
Amphibolites from the Vertiskos and Kerdyllia series of the Serbo-Macedoninn massif, Northern Gre... more Amphibolites from the Vertiskos and Kerdyllia series of the Serbo-Macedoninn massif, Northern Greece, are examined in terms of their mineralogy and petrochemistry. Evidence based on data derived from the geochemistry and mineral parageneses, indicate that the rocks in study arc of basic igneous origin and have metamorphosed in the amphiboli tefacies. The nature of the parental magma, as deduced from the normative compositions and chemical variation trends is in general of tholeiitic compositi on. Discrimination diagrams based on major and trace elements suggest a possible ocean-floor tectonic affinity.
Dolerites from Eastern Varnountas (Florina, W. Macedonia, Greece) are studied. They intrude the C... more Dolerites from Eastern Varnountas (Florina, W. Macedonia, Greece) are studied. They intrude the Carboniferous Varnountas plutonic complex, consisting mainly of granite, granodiorite, monzonite and quartz monzonite, as well as the metamorphic basement, consisting of ortho-and paragneisses and schists. The studied rock-samples show characteristic ophitic texture. The rock-forming minerals are plagioclase, clinopyroxene and olivine. Secondary minerals are amphibole, chlorite, epidote and spinel whereas titanite and rutile occur as accessory minerals. The olivine Fo-content ranges from 51 to 85, with big variations between core and rim at the same sample, and decreases with the increase of SiO 2 of the rocks. Clinopyroxene is augite; its En-content ranges from 40 to 53 and remains constant with the increase of SiO 2 of the rocks. The An-content of plagioclase composition ranges from An57 to An68, increasing with the increase of SiO 2 of the rocks. XRF and ICP-MS-LA techniques were used for the whole-rock analysis for major and trace elements respectively. Their SiO 2 content ranges from 46.8 to 49.4 wt% and the MgO from 7.6 to 11.4 wt%. The whole-rock geochemistry indicates two different groups of samples; one group (LT-HK) having low TiO 2 (0.78-0.90 wt%) and high K2O (0.77-2.00 wt%) and another (HT-LK) with high TiO 2 (1.02-1.34 wt%) and low K2O (0.13-0.32 wt%). The REE patterns show LREE enrichment. LREE/HREE is low ranging from 1.1 to 1.8 apart the more evolved sample L-18 (LT-HK group) having 6.0. LaCN ranges from 14.3 to 27.9 apart again of sample L-18 with LaCN=63.5. The ΣREE is lower in the LT-HK group ranging from 32.70 to 33.93 ppm (L-18=101.28 ppm), relative to the HT-LK group (42.96 to 61.24 ppm). The Eu anomaly ranges from 0.92 to 1.19 without differences between the two groups. According to the classification diagrams the samples belong to the volcanic arc tholeiitic basalts. The enrichment of REE combined with the low LREE/HREE ratio indicates that the studied dolerites originate in a fertile sp-lherzolite. The LT-HK group is the product of 23% partial melting of it and the HT-LK group of 17%. The CrY diagram implies that the two groups evolved through independent fractional crystallization processes. The comparison of the dolerites with the more basic samples of the Varnountas plutonic complex with similar SiO 2 content, shows that the latter are ∼20 times richer in La (LaCN=260-580) with LREE/HREE ratio ranging from 18 to 22, indicating that a common origin is not possible.
Analytical methods.pdf Analitycal methods used to produce data published in the relative paper. F... more Analytical methods.pdf Analitycal methods used to produce data published in the relative paper. Figure A1.pdf Bulk partition coefficients used in the MFC models, reported as linear logarithmic patterns. Inset: absolute values of variations of literature partition coefficients for zircon, titanite, and apatite for REE (GERM database: http://earthref.org/GERM/ for basic - intermediate rocks). A) Rare Earth Elements; B) and C) Trace elements. Cumulus Methodology.docx Elaboration of the methodology used to calculate parental magma and percentages of cumulus minerals of the cumulus process reported in paragraph 5.1 of the manuscript. Figure A2.pdf Triangular diagrams displaying experimental data of melt compositions from different crustal protoliths, compared with the composition of the most evolved high-Ga DAMG. References are also reported.
European Journal of Mineralogy, 1990
Zoned Κ-feldspar phenocrysts from Samothraki Island tertiary plutonic and volcanic rocks have bee... more Zoned Κ-feldspar phenocrysts from Samothraki Island tertiary plutonic and volcanic rocks have been subjected to optical, chemical and XRD analysis. Geochemical data have indicated an increasing trend of Al, Na and Ba from margin to core of the phenocrysts, while Si and K decrease towards the same direction. The statistical processing of chemical data revealed that cation distribution in the various zones is not of the same intensity for every element. Specifically, the greater variation is presented by Ba cations followed by Na. Moreover, XRD analysis shows differentiation of lattice parameters in each zone and a decreasing trend of lattice cell volume from crystal margin to the core. Finally, the calculated temperatures at which the crystal ordering of Si/Al is completed, indicate that magma crystallization has not been normal, since ordering has shown an increasing trend from core to margin.
Bulletin of the Geological Society of Greece, 2004
The Variscan Brnjica granitoids in East Serbia, occurring in the Kucaj Terrane of the Carpatho-Ba... more The Variscan Brnjica granitoids in East Serbia, occurring in the Kucaj Terrane of the Carpatho-Balkanides, are composed of hornblende - biotite tonalité (TON), biotite granodiorite (GRD), twomica granite (TMG) and leucogranite (LG). The rocks analyzed are slightly peraluminous. A preplate collision tectonic environment is supported based on the R1-R2 discrimination diagram. A two-step mixing plus fractional crystallization (MFC) process is considered responsible for the evolution of the Brnjica granitoids. In the 1st step, the parental magma (having the composition of the more basic TON) is forming the mineral assemblage Pl596Biio.3Hbio.7Mto.7Titi.oQzi7.7 by 44% crystallization, and at the same time is mixed (r=0.1) with a magma similar to TMG to give a melt similar to the composition of the less evolved GRD. In the 2nd step, 60% crystallization (Pl39oKfi oBÌ25oZr06Api aMti 4Titi 0QZ303) of the less evolved GRD and a simultaneous mixing with the same acid magma (TMG) but with higher...
This study aims to evaluate the activity concentrations of U, Ra, Th, Th and K along the beaches ... more This study aims to evaluate the activity concentrations of U, Ra, Th, Th and K along the beaches NE Chalkidiki being adjacent to the local granitoids. These ranged from 9.0-63.0, 11.5-62.9, 10.9-54.5, 11.8-56.6 and 27-828 Bq/kg respectively. The (% wt.) heavy magnetic (HM) (allanite, epidote, amphibole, mica, clinopyroxene, magnetite and pyrite) fraction, the heavy non-magnetic (HNM) (zircon, titanite and apatite) fraction and the total heavy fraction (TH), were correlated with the concentrations of the measured radionuclides in the bulk samples. The measured radionuclides in the beach sands were normalized to the respective values measured in the granitic rocks, which are their most probable parental rocks, so as to provide data upon their enrichment or depletion. The annual effective dose varies between 0.003 and 0.009 mSv y for tourists and from 0.012 to 0.037 mSv y for local people working on the beach.
Canadian Journal of Earth Sciences, 1983
The uppermost Paleozoic metaclastic sequences of the Pelagonian zone in northern Greece are conne... more The uppermost Paleozoic metaclastic sequences of the Pelagonian zone in northern Greece are connected to the western margin of the zone. They represent paleogeographic conditions of a deltaic environment and continental slope, which are related to the separation of the Paleozoic continent and the initial rifting in the western ophiolite belt in Greece. The metaclastic sequences define the western (external) boundary of the Pelagonian zone, and are used to find the continuation of this boundary in the Sporades and Oinouses islands in the Aegean Sea, in order to help answer the question of the connection between the Hellenides and the Taurides in Turkey.
Bulletin of the Geological Society of Greece
Emplacement of the Xanthi Plutonic Complex within the Rhodope Massif of N. Greece created an exte... more Emplacement of the Xanthi Plutonic Complex within the Rhodope Massif of N. Greece created an extensive metamorphic aureole around the plutonite. The aureole contains two areas of intense scapolitization in the contacts between granodiorite and biotitegneiss and between monzonite and sandstone, the latter cross-cut by andesite dykes. This paper reports the results of a mineralogical and geochemical study into the formation of the scapolites and particularly the nature of the plutonite-derived hydrothermal fluids from which scapolites were formed.
Bollettino Della Societa Geologica Italiana, 1994
Two apatite samples from the Xanthi pluton (Northern Greece) have been dated by the fission track... more Two apatite samples from the Xanthi pluton (Northern Greece) have been dated by the fission track (FT) method; their confined track lengths were also measured. The FT ages (25.5+ or -1.2 Ma and 26.0+ or -1.8 Ma respectively, corresponding to a closure temperature of about 100 degrees C) are just few million years lower than biotite ages obtained using either K-Ar or Rb-Sr method, which correspond to higher closure temperatures. However, the confined track length distributions (mean length 13.0 mu m, standard deviation 2.0 mu m and skewness -0.84 and -0.50 respectively) indicate that the samples resided for a long time in the partial annealing zone (temperatures between approximately 60 degrees C and approximately 120 degrees C). Apatite FT analysis suggests a simple thermal history: after an early fast cooling, the pluton cooled very slowly. The samples reached low temperatures (
High precision ID-TIMS U-Pb data on single zircons from hornblende-biotite granodiorite (GDR) in ... more High precision ID-TIMS U-Pb data on single zircons from hornblende-biotite granodiorite (GDR) in the Greek part of the batholith and isotope Hf-data of the dated zircons are combined in the present study to elucidate the debatable intrusion age of the pluton and to define its magma source. The intrusion age is determined at 55.93±0.28 Ma by two concordant zircons, one grain shows negligible lead loss, and two zircons reveal lead inheritance, pointing to possible Permo-Triassic and Jurassic ages of the inherited cores/grains. The hafnium isotope characteristics of the analyzed zircons (corrected for an age of 56 Ma) are slightly positive (+1 to +3). They argue that the magma was generated either by mixing of initial mantle and crustal magma or by remelting of former subduction/postcollision related materials. Ar-Ar isotope dating was applied to biotite and potassium feldspar from a hornblende-biotite granodiorite in the Bulgarian part. A plateau age of 49.99±0.88 Ma was obtained on t...
Pure and Applied …, 1996
... intrusions (Fig. la) of varying composition and age which crosscut and overlie a wide range o... more ... intrusions (Fig. la) of varying composition and age which crosscut and overlie a wide range of supracrustal rocks of the Rhodope crystalline basement (eg, Leptokarya-Kirki: ELEFTHERIADIS et aL (1989), DEL MORO et al. (1988 ...
Journal of Sedimentary Research, 2016
Italian Journal of Geosciences, 2016
Mafic microgranular enclaves occur in most calc-alkaline granitoids, and it is widely accepted th... more Mafic microgranular enclaves occur in most calc-alkaline granitoids, and it is widely accepted that they represent the remnants of basic magmas that interacted with more acid magmas. In this work we present new data on mafic microgranular enclaves occurring in the granodiorites of the Sithonia Plutonic Complex (Northern Greece). Enclave properties have been studied using different methods. Quantitative textural analysis has been carried out in order to decipher the crystallization history of enclaves once they have been entrained in the more acid and cooler host magma. In particular, the nucleation density (C), the mode (M) and the crystal index (n) of enclaves has been measured. Along with textural analysis, the size of enclaves has also been estimated using a method that, based on two-dimensional sections of enclaves, allows the estimation of volume of enclaves. Geochemical analyses have been performed to investigate the degree of chemical interaction that enclaves suffered from the host acid magma. The different data sets have been utilized to furnish a general evolutionary model of the magmatic interaction process between the basic and the acid magmas that led to the formation of the granodioritic host rock and related mafic microgranular enclaves. It is concluded that, as the magmatic interaction process proceeded, the crystallization of enclaves involved the nucleation of apatite and epidote (first stage of crystallization) followed by biotite, AE hornblende, plagioclase, and titanite (second stage of crystallization); the last minerals that nucleate were quartz and K-feldspar. During crystallization enclaves underwent contamination by the host acid magma through flow channels opened during the transfer of mineral phases from the host magma to the enclaves. When the two magmas attained similar rheological behaviour a two-end member mixing process was favoured inducing progressively more vigorous mixing dynamics. Volumetric analysis of enclaves indicates that the smaller ones suffered a more intense geochemical interaction compared to the larger ones. We interpret this evidence as being strictly related to the kinematics of the mixing process, the latter governed by chaotic dynamics. Enclaves are viewed as portions of the basic magma that did not mix completely with the acid host magma and survived the mixing process. Host rocks are considered as volumes of the magmatic system where the more efficient mixing dynamics produced different, generally higher, degrees of hybridisation. 174 D. Perugini et al.
Geologica Balcanica
Amphibolites from the Vertiskos and Kerdyllia series of the Serbo-Macedoninn massif, Northern Gre... more Amphibolites from the Vertiskos and Kerdyllia series of the Serbo-Macedoninn massif, Northern Greece, are examined in terms of their mineralogy and petrochemistry. Evidence based on data derived from the geochemistry and mineral parageneses, indicate that the rocks in study arc of basic igneous origin and have metamorphosed in the amphiboli tefacies. The nature of the parental magma, as deduced from the normative compositions and chemical variation trends is in general of tholeiitic compositi on. Discrimination diagrams based on major and trace elements suggest a possible ocean-floor tectonic affinity.
Dolerites from Eastern Varnountas (Florina, W. Macedonia, Greece) are studied. They intrude the C... more Dolerites from Eastern Varnountas (Florina, W. Macedonia, Greece) are studied. They intrude the Carboniferous Varnountas plutonic complex, consisting mainly of granite, granodiorite, monzonite and quartz monzonite, as well as the metamorphic basement, consisting of ortho-and paragneisses and schists. The studied rock-samples show characteristic ophitic texture. The rock-forming minerals are plagioclase, clinopyroxene and olivine. Secondary minerals are amphibole, chlorite, epidote and spinel whereas titanite and rutile occur as accessory minerals. The olivine Fo-content ranges from 51 to 85, with big variations between core and rim at the same sample, and decreases with the increase of SiO 2 of the rocks. Clinopyroxene is augite; its En-content ranges from 40 to 53 and remains constant with the increase of SiO 2 of the rocks. The An-content of plagioclase composition ranges from An57 to An68, increasing with the increase of SiO 2 of the rocks. XRF and ICP-MS-LA techniques were used for the whole-rock analysis for major and trace elements respectively. Their SiO 2 content ranges from 46.8 to 49.4 wt% and the MgO from 7.6 to 11.4 wt%. The whole-rock geochemistry indicates two different groups of samples; one group (LT-HK) having low TiO 2 (0.78-0.90 wt%) and high K2O (0.77-2.00 wt%) and another (HT-LK) with high TiO 2 (1.02-1.34 wt%) and low K2O (0.13-0.32 wt%). The REE patterns show LREE enrichment. LREE/HREE is low ranging from 1.1 to 1.8 apart the more evolved sample L-18 (LT-HK group) having 6.0. LaCN ranges from 14.3 to 27.9 apart again of sample L-18 with LaCN=63.5. The ΣREE is lower in the LT-HK group ranging from 32.70 to 33.93 ppm (L-18=101.28 ppm), relative to the HT-LK group (42.96 to 61.24 ppm). The Eu anomaly ranges from 0.92 to 1.19 without differences between the two groups. According to the classification diagrams the samples belong to the volcanic arc tholeiitic basalts. The enrichment of REE combined with the low LREE/HREE ratio indicates that the studied dolerites originate in a fertile sp-lherzolite. The LT-HK group is the product of 23% partial melting of it and the HT-LK group of 17%. The CrY diagram implies that the two groups evolved through independent fractional crystallization processes. The comparison of the dolerites with the more basic samples of the Varnountas plutonic complex with similar SiO 2 content, shows that the latter are ∼20 times richer in La (LaCN=260-580) with LREE/HREE ratio ranging from 18 to 22, indicating that a common origin is not possible.
Analytical methods.pdf Analitycal methods used to produce data published in the relative paper. F... more Analytical methods.pdf Analitycal methods used to produce data published in the relative paper. Figure A1.pdf Bulk partition coefficients used in the MFC models, reported as linear logarithmic patterns. Inset: absolute values of variations of literature partition coefficients for zircon, titanite, and apatite for REE (GERM database: http://earthref.org/GERM/ for basic - intermediate rocks). A) Rare Earth Elements; B) and C) Trace elements. Cumulus Methodology.docx Elaboration of the methodology used to calculate parental magma and percentages of cumulus minerals of the cumulus process reported in paragraph 5.1 of the manuscript. Figure A2.pdf Triangular diagrams displaying experimental data of melt compositions from different crustal protoliths, compared with the composition of the most evolved high-Ga DAMG. References are also reported.
European Journal of Mineralogy, 1990
Zoned Κ-feldspar phenocrysts from Samothraki Island tertiary plutonic and volcanic rocks have bee... more Zoned Κ-feldspar phenocrysts from Samothraki Island tertiary plutonic and volcanic rocks have been subjected to optical, chemical and XRD analysis. Geochemical data have indicated an increasing trend of Al, Na and Ba from margin to core of the phenocrysts, while Si and K decrease towards the same direction. The statistical processing of chemical data revealed that cation distribution in the various zones is not of the same intensity for every element. Specifically, the greater variation is presented by Ba cations followed by Na. Moreover, XRD analysis shows differentiation of lattice parameters in each zone and a decreasing trend of lattice cell volume from crystal margin to the core. Finally, the calculated temperatures at which the crystal ordering of Si/Al is completed, indicate that magma crystallization has not been normal, since ordering has shown an increasing trend from core to margin.
Bulletin of the Geological Society of Greece, 2004
The Variscan Brnjica granitoids in East Serbia, occurring in the Kucaj Terrane of the Carpatho-Ba... more The Variscan Brnjica granitoids in East Serbia, occurring in the Kucaj Terrane of the Carpatho-Balkanides, are composed of hornblende - biotite tonalité (TON), biotite granodiorite (GRD), twomica granite (TMG) and leucogranite (LG). The rocks analyzed are slightly peraluminous. A preplate collision tectonic environment is supported based on the R1-R2 discrimination diagram. A two-step mixing plus fractional crystallization (MFC) process is considered responsible for the evolution of the Brnjica granitoids. In the 1st step, the parental magma (having the composition of the more basic TON) is forming the mineral assemblage Pl596Biio.3Hbio.7Mto.7Titi.oQzi7.7 by 44% crystallization, and at the same time is mixed (r=0.1) with a magma similar to TMG to give a melt similar to the composition of the less evolved GRD. In the 2nd step, 60% crystallization (Pl39oKfi oBÌ25oZr06Api aMti 4Titi 0QZ303) of the less evolved GRD and a simultaneous mixing with the same acid magma (TMG) but with higher...
This study aims to evaluate the activity concentrations of U, Ra, Th, Th and K along the beaches ... more This study aims to evaluate the activity concentrations of U, Ra, Th, Th and K along the beaches NE Chalkidiki being adjacent to the local granitoids. These ranged from 9.0-63.0, 11.5-62.9, 10.9-54.5, 11.8-56.6 and 27-828 Bq/kg respectively. The (% wt.) heavy magnetic (HM) (allanite, epidote, amphibole, mica, clinopyroxene, magnetite and pyrite) fraction, the heavy non-magnetic (HNM) (zircon, titanite and apatite) fraction and the total heavy fraction (TH), were correlated with the concentrations of the measured radionuclides in the bulk samples. The measured radionuclides in the beach sands were normalized to the respective values measured in the granitic rocks, which are their most probable parental rocks, so as to provide data upon their enrichment or depletion. The annual effective dose varies between 0.003 and 0.009 mSv y for tourists and from 0.012 to 0.037 mSv y for local people working on the beach.
Canadian Journal of Earth Sciences, 1983
The uppermost Paleozoic metaclastic sequences of the Pelagonian zone in northern Greece are conne... more The uppermost Paleozoic metaclastic sequences of the Pelagonian zone in northern Greece are connected to the western margin of the zone. They represent paleogeographic conditions of a deltaic environment and continental slope, which are related to the separation of the Paleozoic continent and the initial rifting in the western ophiolite belt in Greece. The metaclastic sequences define the western (external) boundary of the Pelagonian zone, and are used to find the continuation of this boundary in the Sporades and Oinouses islands in the Aegean Sea, in order to help answer the question of the connection between the Hellenides and the Taurides in Turkey.
Bulletin of the Geological Society of Greece
Emplacement of the Xanthi Plutonic Complex within the Rhodope Massif of N. Greece created an exte... more Emplacement of the Xanthi Plutonic Complex within the Rhodope Massif of N. Greece created an extensive metamorphic aureole around the plutonite. The aureole contains two areas of intense scapolitization in the contacts between granodiorite and biotitegneiss and between monzonite and sandstone, the latter cross-cut by andesite dykes. This paper reports the results of a mineralogical and geochemical study into the formation of the scapolites and particularly the nature of the plutonite-derived hydrothermal fluids from which scapolites were formed.
Bollettino Della Societa Geologica Italiana, 1994
Two apatite samples from the Xanthi pluton (Northern Greece) have been dated by the fission track... more Two apatite samples from the Xanthi pluton (Northern Greece) have been dated by the fission track (FT) method; their confined track lengths were also measured. The FT ages (25.5+ or -1.2 Ma and 26.0+ or -1.8 Ma respectively, corresponding to a closure temperature of about 100 degrees C) are just few million years lower than biotite ages obtained using either K-Ar or Rb-Sr method, which correspond to higher closure temperatures. However, the confined track length distributions (mean length 13.0 mu m, standard deviation 2.0 mu m and skewness -0.84 and -0.50 respectively) indicate that the samples resided for a long time in the partial annealing zone (temperatures between approximately 60 degrees C and approximately 120 degrees C). Apatite FT analysis suggests a simple thermal history: after an early fast cooling, the pluton cooled very slowly. The samples reached low temperatures (
High precision ID-TIMS U-Pb data on single zircons from hornblende-biotite granodiorite (GDR) in ... more High precision ID-TIMS U-Pb data on single zircons from hornblende-biotite granodiorite (GDR) in the Greek part of the batholith and isotope Hf-data of the dated zircons are combined in the present study to elucidate the debatable intrusion age of the pluton and to define its magma source. The intrusion age is determined at 55.93±0.28 Ma by two concordant zircons, one grain shows negligible lead loss, and two zircons reveal lead inheritance, pointing to possible Permo-Triassic and Jurassic ages of the inherited cores/grains. The hafnium isotope characteristics of the analyzed zircons (corrected for an age of 56 Ma) are slightly positive (+1 to +3). They argue that the magma was generated either by mixing of initial mantle and crustal magma or by remelting of former subduction/postcollision related materials. Ar-Ar isotope dating was applied to biotite and potassium feldspar from a hornblende-biotite granodiorite in the Bulgarian part. A plateau age of 49.99±0.88 Ma was obtained on t...
Pure and Applied …, 1996
... intrusions (Fig. la) of varying composition and age which crosscut and overlie a wide range o... more ... intrusions (Fig. la) of varying composition and age which crosscut and overlie a wide range of supracrustal rocks of the Rhodope crystalline basement (eg, Leptokarya-Kirki: ELEFTHERIADIS et aL (1989), DEL MORO et al. (1988 ...
Journal of Sedimentary Research, 2016
Italian Journal of Geosciences, 2016
Mafic microgranular enclaves occur in most calc-alkaline granitoids, and it is widely accepted th... more Mafic microgranular enclaves occur in most calc-alkaline granitoids, and it is widely accepted that they represent the remnants of basic magmas that interacted with more acid magmas. In this work we present new data on mafic microgranular enclaves occurring in the granodiorites of the Sithonia Plutonic Complex (Northern Greece). Enclave properties have been studied using different methods. Quantitative textural analysis has been carried out in order to decipher the crystallization history of enclaves once they have been entrained in the more acid and cooler host magma. In particular, the nucleation density (C), the mode (M) and the crystal index (n) of enclaves has been measured. Along with textural analysis, the size of enclaves has also been estimated using a method that, based on two-dimensional sections of enclaves, allows the estimation of volume of enclaves. Geochemical analyses have been performed to investigate the degree of chemical interaction that enclaves suffered from the host acid magma. The different data sets have been utilized to furnish a general evolutionary model of the magmatic interaction process between the basic and the acid magmas that led to the formation of the granodioritic host rock and related mafic microgranular enclaves. It is concluded that, as the magmatic interaction process proceeded, the crystallization of enclaves involved the nucleation of apatite and epidote (first stage of crystallization) followed by biotite, AE hornblende, plagioclase, and titanite (second stage of crystallization); the last minerals that nucleate were quartz and K-feldspar. During crystallization enclaves underwent contamination by the host acid magma through flow channels opened during the transfer of mineral phases from the host magma to the enclaves. When the two magmas attained similar rheological behaviour a two-end member mixing process was favoured inducing progressively more vigorous mixing dynamics. Volumetric analysis of enclaves indicates that the smaller ones suffered a more intense geochemical interaction compared to the larger ones. We interpret this evidence as being strictly related to the kinematics of the mixing process, the latter governed by chaotic dynamics. Enclaves are viewed as portions of the basic magma that did not mix completely with the acid host magma and survived the mixing process. Host rocks are considered as volumes of the magmatic system where the more efficient mixing dynamics produced different, generally higher, degrees of hybridisation. 174 D. Perugini et al.