The Plan of the Saxon Shore Fort at Richborough

Britannia ◽  
2020 ◽  
Vol 51 ◽  
pp. 147-174
Author(s):  
Tony Wilmott ◽  
Philip Smither
Keyword(s):  
The West ◽  
Supplementary Material ◽  
Wall Foundation

AbstractRecent excavation and coring of the collapsed east wall of the Saxon Shore fort of Richborough has revealed the manner in which the wall collapsed. This led to a re-evaluation of the original siting of the wall, which must have lain to the west of where it is usually depicted. Reassessment of previous excavations, including the examination of original records from the J.P. Bushe-Fox excavations of the 1920s and 1930s leads to the conclusion that the so-called ‘unfinished’ or ‘abandoned’ east wall foundation was in fact the base of the built east wall, from which the collapse derives. A revised fort plan based upon this conclusion is suggested. Supplementary material is available online (https://doi.org/10.1017/S0068113X20000379), and includes additional backing tables and illustrations referenced in the text.

Sediment supply on the West Greenland passive margin: redirection of a large pre-glacial drainage system

2020 ◽  
Vol 177 (6) ◽  
pp. 1149-1160
Author(s):  
Scott Jess ◽  
Alexander L. Peace ◽  
Christian Schiffer
Keyword(s):  
Drainage System ◽  
Sediment Supply ◽  
Passive Margin ◽  
Fluvial System ◽  
The West ◽  
Drainage Systems ◽  
West Greenland ◽  
Igneous Province ◽  
Davis Strait ◽  
Supplementary Material

The Mesozoic–Cenozoic separation of Greenland and North America produced the small oceanic basins of the Labrador Sea and Baffin Bay, connected via a complex transform system through the Davis Strait. During rifting and partial breakup sedimentary basins formed that record the changing regional sediment supply. The onshore and offshore stratigraphy of Central West Greenland outlines the presence of a major fluvial system that existed during the Cretaceous and was later redirected in the Early Cenozoic by the formation of the West Greenland Igneous Province. Hydrological analysis of Greenland's isostatically balanced basement topography outlines two major drainage systems that likely flowed across Greenland prior to the onset of glaciation and emptied into the Sisimiut Basin within the Davis Strait, offshore West Greenland. The course of the northern drainage system suggests that it initially flowed NW into the Cretaceous/Palaeocene Nuussuaq Basin, before being redirected SW around the West Greenland Igneous Province in the Mid-Palaeocene. Moreover, characteristics of these two drainage systems suggest they acted as a single larger fluvial system, prior to the onset of glaciation, that was likely the primary source of sediment across Central West Greenland throughout the Cretaceous and Palaeogene. This scenario provides a greater understanding of the West Greenland margin's late Cenozoic evolution, which differs from previous interpretations that hypothesize a period of considerable post-rift tectonism and uplift. This work highlights the importance of large pre-glacial drainage systems across North Atlantic passive margins and their relevance when studying post-rift stratigraphy in rifted margin settings.Supplementary material: Isostatic modelling, hydrological analysis and chi mapping is available at: https://doi.org/10.6084/m9.figshare.c.5050146

Metamorphism of the Buchan type-area, NE Scotland, and its relation to the adjacent Barrovian domain

2021 ◽  
pp. jgs2021-040
Author(s):  
David R.M. Pattison ◽  
Shantal A. Goldsmith
Keyword(s):  
Field Gradient ◽  
Shear Zone ◽  
Low Grade ◽  
The West ◽  
Geological Evidence ◽  
Content Type ◽  
Type Area ◽  
Igneous Intrusions ◽  
Supplementary Material ◽  
Lower Temperature

The metamorphism of the Buchan block in northeast Scotland, and its relation to the Barrovian domain to its west, have been reassessed from consideration of mineral assemblages, microstructures, phase equilibrium modelling and monazite U-Pb geochronology. Zones of increasing metamorphic grade surround a central low grade domain (biotite zone) and define a northward-opening, U-shaped metamorphic map pattern ascribed to post-metamorphic folding. The eastern and southern Buchan domain show the classic Buchan-type prograde sequence cordierite – andalusite – sillimanite – migmatite/gneiss, representing a metamorphic field gradient of gently increasing pressure between 2.5-3.0 kbar, ∼550 °C and 3.5-4.0 kbar, ∼750 °C. A lower pressure metamorphic field gradient (by less than ∼0.5 kbar) is interpreted for the northeastern Buchan domain. The west Buchan domain shows a prograde sequence of staurolite+andalusite – sillimanite – gneiss/migmatite, representing a metamorphic field gradient higher by ∼1 kbar or less than the classic sequence. Uniquely in the northwestern Buchan domain is a staurolite-cordierite-andalusite domain in which staurolite-bearing schists are interpreted to have been overprinted by cordierite+andalusite assemblages. Monazite U-Pb geochronology of schists and gneisses from the Buchan block, including the Cowhythe and Ellon gneisses, yields ages in the range 470 ±5 Ma, supporting geological evidence that the gneisses are metamorphosed Dalradian strata rather than older basement gneisses. The metamorphic ages are similar to the ages of mafic igneous intrusions in the Buchan block, even though many of the exposed intrusions post-date the regional metamorphic zones. The Buchan metamorphic zones are truncated to the west by the Portsoy-Duchray Hill lineament (PDHL), a ductile shear zone that juxtaposes the Buchan rocks against higher-pressure, lower-temperature (kyanite-bearing) Barrovian schists to the west. A 2-15 km wide corridor of andalusite pseudomorphed by kyanite occurs between the PDHL and the Keith shear zone to its west. Monazite geochronology of the Barrovian rocks west of Portsoy shows little evidence of the c. 470 Ma signature of the Buchan block, instead yielding a dominant cluster of ages at c. 450 Ma and a more poorly defined grouping at c. 490 Ma.Supplementary materials: Analytical methods, thermodynamic modelling; tables S1-S13; figures S1-S5 are available at https://doi.org/10.6084/m9.figshare.c.5536745

Memorandum of Sundry Occurrences During a Passage from Liverpool to Fernando Po in the Schooner Maria of Liverpool, and Whilst Trading on the West African Coast

1993 ◽  
pp. 137-190
Keyword(s):  
West Africa ◽  
West African ◽  
Family Tree ◽  
Valuable Resource ◽  
The West ◽  
West African Coast ◽  
African Coast ◽  
Supplementary Material ◽  
Insight Into

This diary details the life of John Holt during a voyage across West Africa for the purposes of trade. Several entries included detailed accounts of the sale and purchase of goods and provide a valuable resource and insight into his career as a maritime merchant. His travels span the Kroo Coast; Bimbia; Bata; Gaboon; Fernando Po; Georges Bay; the Brass River; Loango Bay; and Mayumba. A small, ten-day voyage to the Krou coast, and Holt’s family tree have been included as supplementary material.

Provenance of Carboniferous sandstones in the central and southern parts of the Pennine Basin, UK: evidence from detrital zircon ages

2020 ◽  
pp. pygs2020-010
Author(s):  
A.C. Morton ◽  
J.I. Chisholm ◽  
D. Frei
Keyword(s):  
Detrital Zircon ◽  
Local Source ◽  
The West ◽  
Content Type ◽  
North West ◽  
Source Areas ◽  
The North ◽  
Isotopic Analyses ◽  
Supplementary Material ◽  
Detrital Zircon Ages

New U-Pb isotopic analyses of detrital zircon grains from Namurian and Westphalian sandstones in the central and south parts of the Pennine Basin are combined with published analyses from the same region, to assess existing views on the nature and location of the source areas that supplied the clastic sediment. The study confirms that most sandstones were derived from distant areas to the north, west and south, and that a local source, in the Wales-Brabant High, also supplied sediment at times. The northern sources are thought to lie mainly in Laurentia (East Greenland), with some input from Baltica (Norway). Most sandstones entering from the west are thought to have been supplied from areas of Avalonian basement, with some components recycled from sediments that were themselves derived from the Caledonian belt that lay to the north. An exception is the Clifton Rock: its source is thought to lie entirely in the Irish Caledonides or in southern Scotland. Sandstones supplied from the south contain significant numbers of late Devonian and Carboniferous grains, indicating the inclusion of material eroded from the active Variscan orogenic belt in Europe. Northern provenance prevailed during Namurian and early Langsettian times, then alternated with western supply until the late Langsettian. Western input then dominated through most of Duckmantian times, until superseded in the late Duckmantian by supply from the Variscan orogen. The Woolley Edge Rock, now shown to be an isolated member of the northern group, entered the area just before the earliest sandstone of Variscan origin.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5174702

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