Sedimentology and palaeogeography of the Upper Old Red Sandstone in the Scottish Border Basin

Abstract

Synopsis The Upper Old Red Sandstone of the southern Scottish Borders is a wholly fluviatile succession. The basal unconformity with the Silurian shows evidence of exhumed, ?pre-Upper O.R.S. topography. Facies association 1 comprises fining-up cycles of sandstone and siltstone deposited by high sinuosity stream systems. Facies association 2 comprises fining-up cycles deposited by low sinuosity streams which may have been braided or non-braided. Facies association 3 comprises conglomerates, pebbly sandstones and sandstones deposited by low sinuosity, braided stream channels. Facies association 4 comprises thick sequences of thinly bedded sandstones, siltstones and conglomerates laid down in persistent flood basins. Palaeocurrents show persistent stream flow from south west to north east and grain and pebble compositions are consistent with igneous and sedimentary sourcelands in Galloway. A gross upward trend to coarser, braided channel facies may have resulted from isostatic uplift in the hinterlands. The southern Border streams formed part of an interior drainage basin (Border Basin) with its centre to the north west of the present day Cheviot hills.

Depositional evolution of a progradational to aggradational, mixed-influenced deltaic succession: Jurassic Tofte and Ile formations, southern Halten Terrace, offshore Norway

“…The erosional base, poor sorting, upward decreasing grain size trend, primary sedimentary structures and absence of bioturbation are all consistent with fluvial channel deposition (Allen, 1965;Leeder, 1973). In places, the repeated interbedding of facies F3a and F3b may record multi-storey stacking of bars, consistent with deposition on rapidly migrating bars, possibly in braided rivers M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT (Miall, 1996;Hartley et al, 2016).…”

Extremely distal fluvial sandstone within the playa system of Arnstadt Formation (Norian, Late Triassic), Central Germany

“…The low-angle cross-beds may form under very shallow energetic flows of upper flow regime (Frostick and Reid 1977;Bridge and Best 1988). The variation from horizontal bedding to ripple bedding may record the fluctuation during the flood event (Leeder 1973). Nevertheless, the association of back flow ripples implies flow separation on the lee side of the moving bedforms under high energy conditions.…”

The origin of the Northumberland basin

“…At the same time an interior drainage basin was established in the Scottish Borders, receiving rivers from Galloway in the SW. and Berwickshire (and beyond) in the N. (Leeder 1973;Fig. 4 of this paper).…”

“…1). Manifestations of differential subsidence and crustal instability included contemporaneous volcanism (Turner 1935;Francis 1967Francis , 1970, syndepositional fault lines and hinges (George 1958;Bott 1967;Johnson 1967), greatly thickened basinal sediments and condensed block sediments (George 1958;Johnson 1967) and vigorous drainage into newly established basins from surrounding block land areas (Freshney 19.61;Read and Johnson 1967;Leeder 1974). Whilst the Midland Valley basin of central Scotland had a previous Lower Devonian history of subsidence (Waterston 1965;Friend 1967), it is likely that the remaining basins were initiated during the late Devonian or early Carboniferous.…”