Scope

Geographical scope

The NSPRMF 2009 spanned the central and southern North Sea and extended into the eastern English Channel and included areas of the sea defined by the exclusive economic zone (EEZ) of England, The Netherlands and Belgium.

The geographical scope of the updated NSPRMF now only includes areas of seabed within England’s EEZ (from high water mark to 200 nautical miles offshore, or to the median line with an adjacent maritime State) and extends the full length of the east coast of England from the Scottish border in the north, to the regional boundary between the South East and South West of England to the west of the Isle of Wight in the English Channel (Figure 1). The Marine Management Organisation (MMO) subdivides the seabed according to English Inshore and Offshore Marine Planning Area boundaries (Figure 2). Figure 2 includes the English Marine Plan Areas.  The English Marine Plans explain the importance of marine aggregate extraction and include policies to ensure its continuation. For example the East Marine Plan notes that marine aggregates ‘play an important role in the supply of aggregates nationally […] with associated benefits such as investment and jobs, and the contribution to the economy both in the United Kingdom and in Europe’ (HM Government 2014, paragraph 385). The plan indicates that public authorities should take into account special polices for aggregate extraction, such as AGG1, AGG2 and AGG3, which give priority to established and applied for aggregate activities.

However, when considering submerged prehistory, geological history and formation processes are the primary factors influencing the nature and distribution of submerged landscapes and cultural heritage. The NSPRMF has therefore been split into four regions according to these factors as outlined in Table 1.

In the coastal zone, the geographical extent of the updated NSPRMF is delimited by Mean Low Water Spring (MLWS) tide. This is of relevance for defining the chronological scope according to sea-level history and as this will avoid duplication of period-specific resource assessments in the coastal/intertidal within existing regional frameworks.

Table 1 NSPRMF region and MMO MPAs

Chronological scope

The chronological scope of the NSPRMF specifically refers to prehistory and does not include historic maritime heritage and other forms of underwater cultural heritage (see Ransley et al. 2013). Submerged prehistory is encountered across very broad spans of time; from the earliest Pleistocene evidence of occupation of the British Isles (Parfitt et al. 2010), to the inundation of the continental shelf during the early Holocene.

Given spatial and temporal variations in sea-level history around the coast (Shennan et al. 2018), and the potential for earlier sites to be discovered, the prehistoric period is loosely defined but includes the Palaeolithic and Mesolithic, although there is some potential for Neolithic and more recent prehistoric archaeological sites and material to be present in coastal zones (below MLWS).

Submerged palaeolandscape assessments are typically undertaken with reference to geological periods (e.g. Quaternary), epochs (e.g. Pleistocene) and sub-epochs (e.g. Devensian) that reflect major climate, sea level or environmental changes, correlated to the Marine Isotope Stage (MIS) record. Here, British nomenclature is adopted to allow correlation with other UK-focussed research frameworks, but correlation between the British and North West European Stages can be made using the formal global chronostratigraphic correlation table of Cohen and Gibbard (2019).

Correlation of Quaternary chronostratigraphy with archaeological periods is required to support a period-led resource assessment. In the context of the updated NSPRMF, four periods are defined below adopting the timeline of the Ancient Human Occupation of Britain project (ahobproject.org/Downloads/Chart.PDF). However, it is recognised that placing an absolute age to the sub-divisions of archaeological and historical time is arbitrary and the resulting temporal horizons may have temporal and spatial variability.

• Lower Palaeolithic: >300 ka
• Middle Palaeolithic: 300 ka to 40 ka
• Upper Palaeolithic: 40 ka to 10 ka
• Mesolithic: 10 ka – 6 ka

For the Pleistocene and Holocene epochs, age estimates are expressed in thousands of years (ka). Absolute dates are given in ka (e.g. luminescence dates) or as either years Before Present (BP) (before 1950 AD), Before Christ (BC) and Anno Domini (AD), or B2k (before 2000 AD). Calibrated radiocarbon age ranges are quoted as calibrated (cal.) BP, BC or AD. There is no standard to report dates relative to a certain datum (e.g. BP or BC/AD). However, here BP is adopted to ensure consistency throughout the resource assessment and any dates referenced relative to cal. BC in source publications have been recalibrated to cal. BP using the calibration curve Intcal20 (Reimer et al. 2020). Any dates are supplemented where relevant with the comparable Marine Isotope Stage (Table 2).

Table 2 Correlation of chronostratigraphy and archaeological periods

*Unnamed Cold Stage, part of the “Wolstonian” in Britain, formal subdivision of this chronostratigraphy is currently debated (Lewis et al. 1993; White et al. 2016; Gibbard et al. 2022).

Image credit: Replica Mesolithic tranchet Axe, Made by Phil Harding, Wessex Archaeology CC BY-NC 2.0