Significant depositional changes offshore the Nile Delta in late third millennium BCE: relevance for Egyptology

Jean-Daniel Stanley,Sarah E. Wedl

doi:10.5194/egqsj-70-83-2021

Abstract

Abstract. No environmental factor has been as critically important for Egypt's ancient society through time as sufficiently high annual flood levels of the Nile River, the country's major source of fresh water. However, interpretation of core analysis shows reduced depositional accumulation rates and altered compositional attributes of the sediment facies deposited seaward of the Nile Delta during a relatively brief period in the late third millennium BCE. These changes record the effects of displaced climatic belts, decreased rainfall, lower Nile flows, and modified oceanographic conditions offshore in the Levantine Basin, primarily from 2300 to 2000 BCE, taking place at the same time as important geological changes identified by study of cores collected in the Nile Delta. It turns out that integrated multi-disciplinary Earth science and archaeological approaches at dated sites serve to further determine when and how such significant changing environmental events had negative effects in both offshore and landward areas. This study indicates these major climatically induced effects prevailed concurrently offshore and in Nile Delta sites and at about the time Egypt abandoned the Old Kingdom's former political system and also experienced fragmentation of its centralized state. In response, the country's population would have experienced diminished agricultural production leading to altered societal, political, and economic pressures during the late Old Kingdom to First Intermediate Period at ca. 2200 to 2050 BCE.

Highlights

Climatic conditions evolved considerably during the Middle to Late Holocene as interpreted by study of the sedimentary record examined in Egypt, northeastern Africa, and the Levant (Said, 1993; Gasse, 2000; Bar-Matthews and Ayalon, 2011; Marriner et al, 2013; Kaniewski et al, 2018)
The present survey focuses primarily on significantly decreased sediment accumulation rates and marked lithofacies changes seaward of the Nile Delta that became more pronounced after the African Humid Period (AHP), from about 5000 to 4000 years ago (Maldonado and Stanley, 1976; Krom et al, 2002; Stanley et al, 2003; Ducassou et al, 2009; Kholeif and Mudie, 2009; Blanchet et al, 2013; Revel et al, 2015)
Revel et al (2015) proposed that decreased proportions of clastic sediments from Ethiopia’s Blue Nile were at times derived from ca. 6 to 3.1 ka. Such changes resulted from altered rainfall patterns in East African highland source areas and increased aridification (Marriner et al, 2013; Revel et al, 2015) that markedly reduced sediment discharged by Nile flows at the coastal margin

Summary

Introduction

Climatic conditions evolved considerably during the Middle to Late Holocene as interpreted by study of the sedimentary record examined in Egypt, northeastern Africa, and the Levant (Said, 1993; Gasse, 2000; Bar-Matthews and Ayalon, 2011; Marriner et al, 2013; Kaniewski et al, 2018). This time span includes the Early Dynastic Period and Old Kingdom to the First Intermediate Period as established archaeologically (Shaw, 2000; Bard, 2008) It was during pharaonic rule of the Old Kingdom that Egypt’s civilization was already reaching stunning levels, including major phases of social and municipal expansion, monumental construction projects along the Nile, and impressive artistic development (Shaw, 2000). Toward the latter part of that millennium, some notable degradation occurred, such as of pyramids (see Fig. 5 for example) during Egypt’s late Old Kingdom and First Intermediate Period. Whether the country’s population could have been affected by such altered climatic conditions at that time will be considered

General background

Early to Middle Holocene Nile offshore sedimentation

Reduced depositional rates after 5000 years BP

Effects of increased aridity and lower Nile flows

Archaeological implications

Findings

Conclusions