CBGp petrofacies thin sections. All samples were stained for calcite and images are shown in plane polarised light, unless otherwise stated. Abbreviations: Alg = algae, Bi = bivalve, Br = bryozoa, Bf = benthic forminifera, Ec = echnoderm, Glc = glauconite, Irf = igneous rock fragment, Pf = planktic forminifera, Por = porosity. A, General view of a Reinga Basin CBGp texture. Echinoderm fragments display well-developed syntaxial overgrowths (red arrows) and fringing cements can be seen in the zooecia of the bryozoa (yellow arrows). Carbonate grains display point to locally sutured contacts. Glauconite occurs and both individual grains (bottom centre) and infilling pores within a benthic foraminifera (bottom right). There is significant intergranular porosity present, confirmed from a second blue epoxy stained thin section from the same sample. The igneous rock fragment (outlined) comprises polycrystalline quartz identified using cross-polarisers. Sample P83293. B, Large Lepidocylcina foraminfera displaying significant intraparticle porosity. The rest of the image comprises fragmental bryozoa debris. Reinga Basin sample P83202. C, General view of a VESPA CBGp sample P84808 containing echinoderm fragments with syntaxial overgrowths (arrows), bryozoa, algae and a benthic agglutinated foraminfera. There is locally significant intergranular porosity. D, Algal dominated part of VESPA CBGp sample P84592 showing common fringing cements around grains. Note the well-preserved echinoderm spine (bottom left). E, Diagenetic fabrics comprising syntaxial overgrowths (red arrows) that post-date fringing cements (yellow arrows) that in places comprise dog tooth spar. A rounded glauconite grain occurs in the interpaticle porosity. Reinga Basin sample P83338. F, Fringing dog-tooth spar cement (yellow arrows) and syntaxial overgrowths (red arrows). Reinga Basin sample P83293.

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... bioclastic grainstone (CBGp) petrofacies A total of eight samples are assigned to this petrofacies, five from the Reinga Basin and three from the VESPA cruise (Table 2). The CBGp samples are macro-bioclast grainstones to local and minor packstones, dominated by large (>mm-scale) allochems that include bryozoans, bivalves, echinoderms, gastropods, foraminifera, and red algae (Figure 2), all of which are commonly very fragmented particularly in VESPA samples. Generally, bryozoan bioclasts ( VESPA sample P84808 contained the only petrographically identified occurrence of an agglutinated foraminifera ( Figure 2C). ...

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... CBGp samples are macro-bioclast grainstones to local and minor packstones, dominated by large (>mm-scale) allochems that include bryozoans, bivalves, echinoderms, gastropods, foraminifera, and red algae (Figure 2), all of which are commonly very fragmented particularly in VESPA samples. Generally, bryozoan bioclasts ( VESPA sample P84808 contained the only petrographically identified occurrence of an agglutinated foraminifera ( Figure 2C). Red algae occur as either discrete bioclasts ( Figure 2D) or encrusting other clasts, most commonly bryozoa, but are also seen encrusting specimens of Lepidocyclina. ...

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... bryozoan bioclasts ( VESPA sample P84808 contained the only petrographically identified occurrence of an agglutinated foraminifera ( Figure 2C). Red algae occur as either discrete bioclasts ( Figure 2D) or encrusting other clasts, most commonly bryozoa, but are also seen encrusting specimens of Lepidocyclina. VESPA sample P84592 has twice the algal material (16%) seen in all other samples. ...

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... and UlmerScholle 2003). After foraminifera and algae, the next most abundant bioclasts are angular to rounded echinoderm plate fragments ( Figure 2A, C), and rare echinoderm spines ( Figure 2D). Bivalve fragments are less common than initially expected, however in some samples where the bioclasts are highly fragmentary it was difficult determining whether fragments were bryozoa or bivalves. ...

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... overgrowths display uniform very dull luminescence under cathodoluminescence spectrometry. The slightly less common, fringing calcite spar cements are present on many bioclasts ( Figure 2E, F, Figure 3D, E) and within bioclast pores, particularly bryozoan zooecia (Figure 2A, 3F) but also locally in foraminiferal chambers. Fringing or isopachous calcite cements occur as radially fibrous to bladed sparry equant crystals ( Figure 2E, F, Figure 3D, F) and dogtooth spar ( Figure 2F, Figure 3F), and are non- luminescent. ...

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... slightly less common, fringing calcite spar cements are present on many bioclasts ( Figure 2E, F, Figure 3D, E) and within bioclast pores, particularly bryozoan zooecia (Figure 2A, 3F) but also locally in foraminiferal chambers. Fringing or isopachous calcite cements occur as radially fibrous to bladed sparry equant crystals ( Figure 2E, F, Figure 3D, F) and dogtooth spar ( Figure 2F, Figure 3F), and are non- luminescent. Inter-and intra-particle pore-filling cements comprise sparry, commonly equant calcite crystals. ...

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... slightly less common, fringing calcite spar cements are present on many bioclasts ( Figure 2E, F, Figure 3D, E) and within bioclast pores, particularly bryozoan zooecia (Figure 2A, 3F) but also locally in foraminiferal chambers. Fringing or isopachous calcite cements occur as radially fibrous to bladed sparry equant crystals ( Figure 2E, F, Figure 3D, F) and dogtooth spar ( Figure 2F, Figure 3F), and are non- luminescent. Inter-and intra-particle pore-filling cements comprise sparry, commonly equant calcite crystals. ...