Continuous vegetation record of the Greater Cape Floristic Region (South Africa) covering the past 300 000 years (IODP U1479)

Lydie M Dupont,David Braun,John Tyler Faith,Xueqin Zhao,Christopher Charles

doi:10.5194/cp-18-1-2022

Abstract

Abstract. The Greater Cape Floristic Region (GCFR) of South Africa is a biodiversity hotspot of global significance, and its archeological record has substantially contributed to the understanding of modern human origins. For both reasons, the climate and vegetation history of southwestern South Africa is of interest to numerous fields. Currently known paleoenvironmental records cover the Holocene, the last glacial–interglacial transition and parts of the last glaciation but do not encompass a full glacial–interglacial cycle. To obtain a continuous vegetation record of the last Pleistocene glacial–interglacial cycles, we studied pollen, spores and micro-charcoal of deep-sea sediments from IODP Site U1479 retrieved from SW of Cape Town. We compare our palynological results of the Pleistocene with previously published results of Pliocene material from the same site. We find that the vegetation of the GCFR, in particular fynbos and afrotemperate forest, responds to precessional forcing of climate. The micro-charcoal record confirms the importance of fires in the fynbos vegetation. Ericaceae-rich and Asteraceae-rich types of fynbos could extend on the western part of the Paleo-Agulhas Plain (PAP), which emerged during periods of low sea level of the Pleistocene.

Highlights

Southwestern South Africa is a fascinating region for both its unique flora and for its role in our knowledge of the origin of modern human behavior (Fig. 1)
To provide a regional framework of climate and vegetation dynamics across multiple glacial–interglacial cycles, we report a record of the vegetation in the Greater Cape Floristic Region (GCFR) using pollen and spores recovered from deep-sea sediments of IODP Site U1479 (Fig. 1), which were retrieved offshore almost 160 km SW of Cape Town (Hall et al, 2017)
The seafloor at the site is bathed in North Atlantic Deep Water, while the surface ocean is influenced by the waters of the Agulhas Current, which retroflects from the Agulhas Bank at the southern tip of Africa and flows eastwards as the Agulhas Return Current

Summary

Introduction

Southwestern South Africa is a fascinating region for both its unique flora and for its role in our knowledge of the origin of modern human behavior (Fig. 1). The paleoenvironmental records of the GCFR sites covering at least part of the last glaciation are varied and detailed They include stable carbon and oxygen isotope records of speleothems (Talma and Vogel, 1992; BarMatthews et al, 2010; Braun et al, 2019, 2020), stable isotopes from hyrax middens (Chase et al, 2011, 2012, 2017, 2018, 2019), mammal bone assemblages (Klein, 1983; Avery, 1982; Faith, 2013; Klein and Cruz-Uribe, 2016, 2000; Nel and Henshilwood, 2016; Nel et al, 2018; Forrest et al, 2018), microwear patterns and stable isotopes of fossil teeth (Copeland et al, 2016; Sealy et al, 2016, 2020; Hodgkins et al, 2020; Williams et al, 2020), charcoal (Cartwright and Parkington, 1997; Cowling et al, 1999; Cartwright, 2013; Parkington et al, 2000), phytoliths Dupont et al.: A 300 kyr long vegetation record of the GCFR

Methods

Findings

Discussion

Conclusion