Sedimentology and stratigraphy of a transgressive, muddy gravel beach: Waterside Beach, Bay of Fundy, Canada

Abstract

Sediments exposed at low tide on the transgressive, hypertidal (>6 m tidal range) Waterside Beach, New Brunswick, Canada permit the scrutiny of sedimentary structures and textures that develop at water depths equivalent to the upper and lower shoreface. Waterside Beach sediments are grouped into eleven sedimentologically distinct deposits that represent three depositional environments: (1) sandy foreshore and shoreface; (2) tidal-creek braid-plain and delta; and, (3) wave-formed gravel and sand bars, and associated deposits. The sandy foreshore and shoreface depositional environment encompasses the backshore; moderately dipping beachface; and a shallowly seaward-dipping terrace of sandy middle and lower intertidal, and muddy sub-tidal sediments. Intertidal sediments reworked and deposited by tidal creeks comprise the tidal-creek braid plain and delta. Wave-formed sand and gravel bars and associated deposits include: sediment sourced from low-amplitude, unstable sand bars; gravel deposited from large (up to 5AE5 m high, 800 m long), landward-migrating gravel bars; and zones of mud deposition developed on the landward side of the gravel bars. The relationship between the gravel bars and mud deposits, and between mud-laden sea water and beach gravels provides mechanisms for the deposition of mud beds, and muddy clast-and matrix-supported conglomerates in ancient conglomeratic successions. Idealized sections are presented as analogues for ancient conglomerates deposited in transgressive systems. Where tidal creeks do not influence sedimentation on the beach, the preserved sequence consists of a gravel lag overlain by increasingly finer-grained shoreface sediments. Conversely, where tidal creeks debouch onto the beach, erosion of the underlying salt marsh results in deposition of a thicker, more complex beach succession. The thickness of this package is controlled by tidal range, sedimentation rate, and rate of transgression. The tidal-creek influenced succession comprises repeated sequences of: a thin mud bed overlain by muddy conglomerate, sandy conglomerate, a coarse lag, and capped by trough cross-bedded sand and gravel.

An interglacial polar bear and an earlyWeichselian glaciation atPoolepynten, westernSvalbard

“…An alternative interpretation of unit A2 is that it could possibly have formed as a migrating gravel bar, developed under high‐energy conditions in the subtidal zone (lower shoreface), but we did not observe clear dipping foresets, usually associated with migrating gravel bars (Dashtgard et al . ). Regardless, gravel‐bar formation at this location in the stratigraphy would imply marine regression after the deposition of unit A1.…”

“…flat-lying to slightly seaward-dipping clasts, subhorizontal stratification) are typical features of beach sediments (Massari & Parea 1988;Bluck 1999) and are the main basis for our interpretation of A2 as shoreface beach gravels. An alternative interpretation of unit A2 is that it could possibly have formed as a migrating gravel bar, developed under high-energy conditions in the subtidal zone (lower shoreface), but we did not observe clear dipping foresets, usually associated with migrating gravel bars (Dashtgard et al 2006). Regardless, gravel-bar formation at this location in the stratigraphy would imply marine regression after the deposition of unit A1.…”

“…We interpret unit A2 to be beachface sediments (Dashtgard et al . ), based on the size, sorting and orientation of particles and the low‐angle stratification, deposited in the surf‐to‐swash zone of the beach. The upper contact to unit A3 is undulating and erosional (Fig.…”

An interglacial polar bear and an earlyWeichselian glaciation atPoolepynten, westernSvalbard

“…An alternative interpretation of unit A2 is that it could possibly have formed as a migrating gravel bar, developed under high‐energy conditions in the subtidal zone (lower shoreface), but we did not observe clear dipping foresets, usually associated with migrating gravel bars (Dashtgard et al . ). Regardless, gravel‐bar formation at this location in the stratigraphy would imply marine regression after the deposition of unit A1.…”

“…flat-lying to slightly seaward-dipping clasts, subhorizontal stratification) are typical features of beach sediments (Massari & Parea 1988;Bluck 1999) and are the main basis for our interpretation of A2 as shoreface beach gravels. An alternative interpretation of unit A2 is that it could possibly have formed as a migrating gravel bar, developed under high-energy conditions in the subtidal zone (lower shoreface), but we did not observe clear dipping foresets, usually associated with migrating gravel bars (Dashtgard et al 2006). Regardless, gravel-bar formation at this location in the stratigraphy would imply marine regression after the deposition of unit A1.…”

“…We interpret unit A2 to be beachface sediments (Dashtgard et al . ), based on the size, sorting and orientation of particles and the low‐angle stratification, deposited in the surf‐to‐swash zone of the beach. The upper contact to unit A3 is undulating and erosional (Fig.…”

Multi‐sequential order transgressive cycles from the last interglacial to the Holocene revealed by deep‐core sediment facies analysis in the Baeksu tidal deposits, south‐west coast of Korea

“…Hence, the muddy gravels with their interbedded mud layers are interpreted to represent a gravel bar resting on top of a mud deposit in protected troughs or sinks. It results in mud‐infilling of the spaces between the gravel clasts (Dashtgard et al., 2006). In contrast, the mud‐free gravel beds are interpreted as bar crests.…”

Interplay of tectonism and eustasy during the Early Permian icehouse: Southern Sydney Basin, southeast Australia

“…These settings are affected by strong wave energies and by strong tides, with the latter facilitating the lateral migration of wave zones along the depositional profile of the beach and shoreface (Dashtgard et al, ; Dashtgard et al, ). Despite their common occurrence in the modern environments (e.g., Anthony, Levoy, Monfort, & Degryse‐Kulkarni, ; Levoy, Monfort, & Larsonneur, ), our knowledge about the impact of tides on the shoreface relies on few modern and ancient examples (Dashtgard & Gingras, ; Dashtgard, Gingras, & Butler, ; Frey & Dashtgard, ), and the available criteria for the recognition of TMS are restricted to a single modern (Dashtgard et al, ) and a single ancient example (Ainsworth et al, ). The research of Ainsworth et al .…”

An interglacial polar bear and an earlyWeichselian glaciation atPoolepynten, westernSvalbard

“…An alternative interpretation of unit A2 is that it could possibly have formed as a migrating gravel bar, developed under high‐energy conditions in the subtidal zone (lower shoreface), but we did not observe clear dipping foresets, usually associated with migrating gravel bars (Dashtgard et al . ). Regardless, gravel‐bar formation at this location in the stratigraphy would imply marine regression after the deposition of unit A1.…”

“…flat-lying to slightly seaward-dipping clasts, subhorizontal stratification) are typical features of beach sediments (Massari & Parea 1988;Bluck 1999) and are the main basis for our interpretation of A2 as shoreface beach gravels. An alternative interpretation of unit A2 is that it could possibly have formed as a migrating gravel bar, developed under high-energy conditions in the subtidal zone (lower shoreface), but we did not observe clear dipping foresets, usually associated with migrating gravel bars (Dashtgard et al 2006). Regardless, gravel-bar formation at this location in the stratigraphy would imply marine regression after the deposition of unit A1.…”

“…We interpret unit A2 to be beachface sediments (Dashtgard et al . ), based on the size, sorting and orientation of particles and the low‐angle stratification, deposited in the surf‐to‐swash zone of the beach. The upper contact to unit A3 is undulating and erosional (Fig.…”

Multi‐sequential order transgressive cycles from the last interglacial to the Holocene revealed by deep‐core sediment facies analysis in the Baeksu tidal deposits, south‐west coast of Korea

“…Hence, the muddy gravels with their interbedded mud layers are interpreted to represent a gravel bar resting on top of a mud deposit in protected troughs or sinks. It results in mud‐infilling of the spaces between the gravel clasts (Dashtgard et al., 2006). In contrast, the mud‐free gravel beds are interpreted as bar crests.…”

Interplay of tectonism and eustasy during the Early Permian icehouse: Southern Sydney Basin, southeast Australia

“…These settings are affected by strong wave energies and by strong tides, with the latter facilitating the lateral migration of wave zones along the depositional profile of the beach and shoreface (Dashtgard et al, ; Dashtgard et al, ). Despite their common occurrence in the modern environments (e.g., Anthony, Levoy, Monfort, & Degryse‐Kulkarni, ; Levoy, Monfort, & Larsonneur, ), our knowledge about the impact of tides on the shoreface relies on few modern and ancient examples (Dashtgard & Gingras, ; Dashtgard, Gingras, & Butler, ; Frey & Dashtgard, ), and the available criteria for the recognition of TMS are restricted to a single modern (Dashtgard et al, ) and a single ancient example (Ainsworth et al, ). The research of Ainsworth et al .…”

An interglacial polar bear and an earlyWeichselian glaciation atPoolepynten, westernSvalbard

“…An alternative interpretation of unit A2 is that it could possibly have formed as a migrating gravel bar, developed under high‐energy conditions in the subtidal zone (lower shoreface), but we did not observe clear dipping foresets, usually associated with migrating gravel bars (Dashtgard et al . ). Regardless, gravel‐bar formation at this location in the stratigraphy would imply marine regression after the deposition of unit A1.…”

“…flat-lying to slightly seaward-dipping clasts, subhorizontal stratification) are typical features of beach sediments (Massari & Parea 1988;Bluck 1999) and are the main basis for our interpretation of A2 as shoreface beach gravels. An alternative interpretation of unit A2 is that it could possibly have formed as a migrating gravel bar, developed under high-energy conditions in the subtidal zone (lower shoreface), but we did not observe clear dipping foresets, usually associated with migrating gravel bars (Dashtgard et al 2006). Regardless, gravel-bar formation at this location in the stratigraphy would imply marine regression after the deposition of unit A1.…”

“…We interpret unit A2 to be beachface sediments (Dashtgard et al . ), based on the size, sorting and orientation of particles and the low‐angle stratification, deposited in the surf‐to‐swash zone of the beach. The upper contact to unit A3 is undulating and erosional (Fig.…”

Multi‐sequential order transgressive cycles from the last interglacial to the Holocene revealed by deep‐core sediment facies analysis in the Baeksu tidal deposits, south‐west coast of Korea

“…Hence, the muddy gravels with their interbedded mud layers are interpreted to represent a gravel bar resting on top of a mud deposit in protected troughs or sinks. It results in mud‐infilling of the spaces between the gravel clasts (Dashtgard et al., 2006). In contrast, the mud‐free gravel beds are interpreted as bar crests.…”

Interplay of tectonism and eustasy during the Early Permian icehouse: Southern Sydney Basin, southeast Australia

“…These settings are affected by strong wave energies and by strong tides, with the latter facilitating the lateral migration of wave zones along the depositional profile of the beach and shoreface (Dashtgard et al, ; Dashtgard et al, ). Despite their common occurrence in the modern environments (e.g., Anthony, Levoy, Monfort, & Degryse‐Kulkarni, ; Levoy, Monfort, & Larsonneur, ), our knowledge about the impact of tides on the shoreface relies on few modern and ancient examples (Dashtgard & Gingras, ; Dashtgard, Gingras, & Butler, ; Frey & Dashtgard, ), and the available criteria for the recognition of TMS are restricted to a single modern (Dashtgard et al, ) and a single ancient example (Ainsworth et al, ). The research of Ainsworth et al .…”