42 / Sub-
arkose / Grain-supported texture characterized by the predominance of monocrystalline quartz, mainly angular in shape, with some sub-rounded grains. Polycrystalline quartz grains are very rare; the remains consist of glauconite, plagioclase, K-feldspars, opaque minerals, chert and zircon. Scarce silica cement was observed. The roundness of clasts varies from sub-angular to sub-rounded; the sphericity varies from high to low. The aggregate is well sorted with a mean grain size of 200 μm. This sample is very compact with a high average of corroded glauconite probably due to fluid circulation. The XRD-mineralogical analysis evidences abundant quartz, a low amount of K-feldspars and plagioclase, and a trace of glauconite.
16 / Quartz-arenite / Grain-supported texture characterized by a high amount of monocrystalline quartz, the remaining components consist of K-feldspars, opaque minerals, plagioclase, green-schist clasts (mainly of chloritic-sericitic quartzitic schists), chert, glauconite and heavy minerals (zircon and garnets). Cement is sparitic. The roundness of the clasts varies from sub-rounded to sub-angular while the sphericity ranges from medium to low. The aggregate is well sorted with a mean grain size of 300 μm. The quartz shows angular and conchoid edges. The XRD-mineralogical analysis evidences quartz and trace of dolomite, calcite, plagioclase, chlorite, hematite and glauconite.
20 / Quartz-arenite / Grain-supported texture characterized by a high amount of monocrystalline quartz. The remains consist of K-feldspars, plagioclase, opaque minerals, glauconite and green-schist clasts. Some heavy minerals (zircon and garnets) were also found. The roundness of clasts varies from sub-angular to sub-rounded while the sphericity is from medium to high. The aggregate is well sorted with a mean grain size of 250 μm. The grains are slightly oriented. Pores are scant and cemented. The above characteristics may evidence middle to slow sedimentation. The XRD-mineralogical analysis evidences abundant quartz and trace amounts of calcite, K-feldspars and chlorite.
23 / Quartz-arenite / Grain-supported texture characterized by the abundance of sub-angular (with undulosity) monocrystalline quartz. The remains consist of glauconite, plagioclase, K-feldspars, opaque minerals, chert, zircon and one sub-rounded green-schist clasts. Some areas show broken grains. The roundness of clasts varies from sub-angular to sub-rounded while the sphericity ranges from medium to high. The aggregate is well sorted with a mean grain size of 200 μm. The quartz-grain rims are very fractured, deeply corroded, and merged with the pore-filling cement from chalcedony to microcrystalline quartz. It is possible that the amorphous silica (primary cement) was recrystallized under high pressure. Some areas show broken grains. The cement is both sparitic and siliceous. The grains are slightly oriented. Pores are scant and cemented. The above characteristics may evidence slow sedimentation. The XRD-mineralogical analysis evidences abundant quartz, scant calcite and plagioclase, with trace of K-feldspars, dolomite and hematite.
30 / Quartz-arenite / Grain-supported texture characterized by a high amount of monocrystalline quartz, the remains consisting of K-feldspars, opaque minerals, glauconite, and plagioclase. Scarce carbonate cement is present. The roundness of clasts varies from sub-angular to sub-rounded with high sphericity. The aggregate is well sorted with a mean grain size of 400 μm. The rims of the quartz grains are very fractured, deeply corroded, and merged with the pore-filling sparite cement. Cement is very rare, consisting of chalcedony and microcrystalline quartz. It is possible that the amorphous silica was the primary cement and, under high pressure, it has been recrystallized. The XRD-mineralogical analysis evidences abundant quartz, scant calcite, and traces of K-feldspars, plagioclase and dolomite.
95 / Sub-arkose / Grain-supported texture characterized by a high percentage of angular monocrystalline quartz grains (with undulate extinction); the remains consist of clasts of plagioclase, K-feldspars, glauconite, muscovite, chert, opaque minerals, and very rare micaschist lithoclasts that are not rounded. Rare rutile and garnets have also been found. The cement is mainly siliceous, with scarce carbonate cement also present. The aggregate is not sorted, with a mean grain size of 350 μm. The quartz-grain rims are very fractured, deeply corroded and merged with the pore-filling silica cement. The roundness of the clasts varies from angular to rounded; the sphericity varies from medium to high. The XRD-mineralogical analysis evidences abundant calcite and scarce K-feldspars and plagioclase, with trace of chlorite, hematite and glauconite.
98 / Quartz-arenite / Grain-supported texture, the most abundant component is monocrystalline quartz grains. The other components consist of plagioclase, K-feldspars replaced by sericite, glauconite, opaque minerals, green schist lithic grains (quartzitic-sericitic type) and chert. Rounded zircon has also been noticed. Cement is siliceous; scarce carbonate cement has also been observed. The roundness of clasts varies from angular to sub-rounded; the sphericity varies from medium to high. The aggregate is well sorted with a mean grain size of 300 μm. The quartz-grain rims are very fractured, deeply corroded, and merged with the pore-filling silica cement. There is a slight presence of Fe-oxide. The XRD-mineralogical analysis indicates abundant quartz, with trace of K-feldspars, plagioclase and chlorite.
102 / Quartz-arenite / Grain-supported and slightly oriented texture, characterized by the high percentage of monocrystalline quartz grains with sutured rims; the other components consist of glauconite, plagioclase, opaque minerals, chert, K-feldspars, some muscovite flakes and sub-angular schist grains. Zircon and garnets have also been observed. Silica cement, very oxidized, has been noted. The roundness of clasts varies from sub-angular to angular while the sphericity ranges from medium to low. The aggregate is moderately sorted with a mean grain size of 300 μm. The XRD-mineralogical analysis indicates very abundant quartz quantity, with trace of K-feldspars, plagioclase, chlorite, hematite, and glauconite.
11 / Quartz-arenite / Cement to grain-supported texture composed mainly of monocrystalline quartz, while other minerals consist of fine-grained quartz, plagioclase, K-feldspars, glauconite, chert, opaque minerals, muscovite, biotite, and rare zircon grains. The quartz grains rims are deeply corroded. A dolomitic/calcitic microsparitic cement is present. The roundness of clasts varies from sub-angular to sub-rounded; the sphericity ranges from medium to high. The aggregate is well sorted with a mean grain size of 250 μm. It consists of a immature sediment with a jointing filled by calcite. The XRD-mineralogical analysis evidences abundant quartz and moderate amounts of dolomite, with low quantities of calcite, plagioclase, K-feldspars and hematite.
10 / Quartz-arenite / Grain-supported texture characterized by the abundance of monocrystalline quartz. The remains consist of opaque minerals, K-feldspars, plagioclase, muscovite, zircon and rare green-schist clasts. Silica cement is abundant while scarce sparitic cement is also present. The roundness of clasts varies from sub-angular tosub-rounded; the sphericity varies from medium to low. The aggregate is well sorted with a mean grain size of 400 μm. The quartz grains have very fractured rims, are deeply corroded and merge with the pore-filling cement from chalcedony to microcrystalline quartz. It is possible that the amorphous silica, which was the primary cement, has been re-crystallized under high pressure. The grains are very poorly oriented. Few poresare cemented. The above characteristics may indicate middle to slow sedimentation. The XRD-mineralogical analysis evidences abundant quartz and a low amount of dolomite with very few quantities of calcite, plagioclase, and K-feldspars.
7a / Micro-crystalline chalcedony / Microcrystalline quartz background (92%) with a rectangular system of fractures filled with calcite (8%) of neo-formation. The XRD-mineralogical analysis evidences abundant quartz and a very low quantity of calcite.
7b / Micro-crystalline chalcedony / Microcrystalline quartz background (90%) with rectangular system of fractures filled with calcite (10%) of neo-formation. Siliceous lithofacies (Lithotype 4, fig 8) such as chert (in bed and lens), radiolarites, siliceous shales are also present in other members.
89a / Glauconitic sub-litharenite / Mostly grain-supported texture characterized by a carbonate matrix. The siliciclastic fraction is constituted mostly by grains of monocrystalline quartz, with corroded rims and calcite substitution. Glauconite might reach 18%. The remaining grains consist of phyllosilicates (sericite, muscovite), K-feldspars, plagioclase and heavy minerals. There are also bioclasts (benthonic and planktonic foraminifers), and some globigerina lodges are filled with pyrite. The roundness of the clasts varies from sub-angular to sub-rounded; the sphericity varies from medium to high. Sub-angular to sub-rounded quartz with middle sphericity has been observed. Rounded to sub-rounded glauconite with medium to high sphericity is present. The XRD-mineralogical analysis evidences abundant quartz and scant calcite, K-feldspars and plagioclase, with traces of chlorite and glauconite.
89b / Glauconitic sub-litharenite / The texture is mostly matrix-supported and less grain-supported. The cement is microsparitic carbonate. The siliciclastic fraction is constituted mostly by grains of monocrystalline quartz with corroded rims and calcite substitution. Glauconite reaches up to 14% and the remaining grains consist of sericite, muscovite and plagioclase. There are also bioclasts of benthonic and planktonic foraminifers, and some of globigerina lodges are filled with pyrite. The roundness of clasts varies from sub-angular to sub-rounded; the sphericity varies from medium to high. Sub-angular to sub-rounded quartz with medium sphericity was found. Rounded to sub-rounded with medium to high sphericity glauconite is also present. The XRD-mineralogical analysis evidences abundant quartz and scarce calcite and K-feldspars, with traces of plagioclase, chlorite and glauconite.
77a / Sub-litharenite / The texture is mostly matrix-supported and less grain-supported. Carbonate matrix and sparitic cement are present. Sub-angular grains of monocrystalline quartz, with corroded rims are the most abundant component. The remaining grains consist of bioclasts (foraminifers), feldspars, mainly plagioclases, glauconite, heavy minerals and lithic fragments, mostly carbonates. The roundness of clasts varies from sub-angular to sub-rounded; the sphericity varies from medium to low. Rounded to sub-rounded with medium to high sphericity oxidized glauconite was found. The XRD-mineralogical analysis shows abundant quartz, low amounts of calcite and traces of K-feldspars, plagioclase, chlorite and glauconite.
77b / Sub-litharenite / The texture is mostly matrix-supported and less grain-supported, characterized by carbonate microsparitic cement. The main components are sub-angular grains of monocrystalline quartz with corroded rims and of glauconite; the other grains consist of feldspars, mainly plagioclase, mica, chlorite and foraminifer bioclasts. The roundness of the clasts varies from sub-angular to sub-rounded; the sphericity varies from medium to low. Sub-angular to sub-rounded quartz with medium sphericity has been found. Rounded to sub-rounded with medium to high sphericity glauconites have been observed.
76 / Calcarenite / The texture is matrix-supported and it is very rich in bioclastic material represented by abundant sponge spicules, replaced by calcite or pyrite, and rare benthonic foraminifers. Scattered arenitic to siltitic grains of quartz (mainly monocrystalline) with deeply corroded rims are present, rare plagioclase, little syngenetic glauconite and chert (after chalcedony). Sub-angular to sub-rounded quartz with medium sphericity was observed. Rounded to subrounded corroded glauconite with medium to high sphericity is present. Inter-granular material is represented by either carbonate matrix or sparitic cement. The XRD-mineralogical analysis indicates abundant quartz and calcite, scarce plagioclase, with trace amounts of K-feldspars, chlorite and glauconite.
74 / Calcarenite / The texture is matrix-supported and it is characterized by abundant sponge spicules replaced by spatic calcite and benthonic foraminifers with lodges filled by pyrite. The detrital material (<10%) consists of monocrystalline quartz, glauconite and opaque minerals. Roundering and sphericity of quartz varies from low to medium. High roundering and medium sphericity of glauconite have been noted. The XRD-mineralogical analysis shows abundant quartz and calcite, scant plagioclase, and traces of chlorite, K-feldspars, hematite, and glauconite.
130 / Calcarenite / The texture varies from grain to matrix-supported with a poor aggregate sorting. Carbonate cement (from sparitic to microsparitic) and matrix are present. The main components are metamorphic lithic fragments (green schists), plagioclase, monocrystalline quartz, chert, very scarce glauconite and bioclasts (algae, benthonic foraminifers and echinid pins). Rounded to sub-angular quartz with low to medium sphericity has been observed. The presence of well-preserved echinoids fragments could indicate the proximity of the basin to the coast. The XRD-mineralogical analysis shows abundant calcite, moderate amounts of quartz, scarce plagioclase, chlorite and glauconite, with traces of dolomite.
112 / Sub-litarenite / The texture is mostly cement-supported. The clastic grains consist of deeply corroded monocrystalline quartz, metamorphic lithic fragments with a fine texture (green schists), plagioclase, rare polycrystalline quartz, chert, muscovite, K-feldspars, carbonate clasts, syn-genetic glauconite, heavy minerals and algal bioclasts. The shape of clasts vary from angular to rounded with a sphericity ranging from medium to low. The XRD-mineralogical analysis shows abundant quartz, medium amounts of calcite, scant plagioclase and traces of chlorite, glauconite and hematite.
110 / Calcarenite / The texture is matrix-supported with a poor sorting aggregate. The main components are limestone fragments, monocrystalline, mainly angular, quartz, lithic grains of green schists (chloritous, sericitic or quartzitic-chloritous and quartzitic-sericitic), rare chert, K-feldspars, plagioclase, polycrystalline quartz and fragments of coralline algae. The roundness of the components varies from high to low, with low to medium sphericity. Very rare rounded glauconite with medium to high sphericity is also present. Quartz is related to metamorphic rocks according to its undulate extinction. The XRD-mineralogical analysis shows abundant quantity of calcite, a low amount of quartz, with traces of chlorite, dolomite and glauconite.
Appendix 1 - Extended petrographic description of arenites (see also photos in Fig. 4) studied in the Vrancea Nappe succession.
Appendix 1 (photos in Fig 4)