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Table 2 Lithofacies at the “Quebrada Corralito” section of the Querales Formation

From: Palaeontology, sedimentology, and biostratigraphy of a fossiliferous outcrop of the Early Miocene Querales Formation, Falcón Basin, Venezuela

Facies

Lithology

Description

Bioturbation

Depositional interpretation

Fm

Massive mudstone

Black–blue colour. Pyrite disseminated widely; few bioclasts. Aturia sp. and few microfossils

Absent

Fine-grained material decantation. Low energy deposition dominated by low energy, in an anoxic environment. Offshore (inner to outer platform)

Fl

Laminated and bioclastic mudstone

Dark grey colour, abundant bioclasts, macroinvertebrates and microinvertebrates. Scarce presence of mudstone fraction. Transitional passage

Absent

Fine-grained material decantation and traction transport to a low energy environment which generated the accumulation of bioclasts. Shoreface to Offshore (inner platform)

Ll

Laminated mudstone with plant debris

Brown–green colour. Plant debris and amber nodules. Transitional passage

Absent

Deposition via decanting in low-mid energy environment. “Shoreface” environment

Htp

Heterolithic pelite

Dark grey colour, layered pelites alternate with thin layers of fine-grained sandstones and light-coloured limestones. Heterolithic levels are lenticular and are combined with flow ripple laminations. Inverse grading

Scarce

Decantation predominates over traction transport. Offshore transition to low Shoreface

Hta

Sandy heterolithic levels

Dark grey, layer laminated shales alternate with thin layers of fine and mid-grained sandstones, light yellow in colour, with trough cross-bedding. Flaser bedding, in which cross-laminated sand contains mud streaks. Strata thickening upwards

Scarce, small burrows of cf. Skolithos isp.

Tractive process predominates over decantation process. Action of orbital flows in subaqueous environments, Lower to middle Shoreface

Sm

Sandstone

Fine and mid-grained sandstones, brown–yellow in colour, with massive structure. Amalgamated sandstone levels with iron oxide specks

Abundant, Thalassinoides isp. and Planolites isp.

Tractive deposits of mid to high energy that lost their primary mechanical structure by synmixis and bioturbation process. Well-oxygenated substrate. High Shoreface