Late Holocene palaeolimnology of Bal Lake, Northern Nigeria, a multidisciplinary study

Holmes, Jonathan A.; Allen, Mike; Street-Perrott, F. Alayne; Ivanovich, Μ.; Perrott, RA; Waller, Martyn

doi:10.1016/s0031-0182(98)00182-5

Cited by 41 publications

(21 citation statements)

References 26 publications

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“…1). Some results from these investigations have been published previously (Holmes et al, 1997(Holmes et al, , 1999aSalzmann and Waller, 1998;Street-Perrott et al, 2000;Waller et al, 2007): here, we report sedimentological and mineral magnetic data for a well-dated 690 cm thick sediment sequence from Jikariya Lake and compare them with high-resolution pollen curves (Waller et al, 2007). Despite the existence of well-dated palaeoenvironmental records from two nearby sites investigated under the SAHEL project, together with additional sites further to the east (Kaigama and Kuluwu: Salzmann and Waller, 1998;Fig.…”

Section: Introductionmentioning

confidence: 74%

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Holocene environmental change in the West African Sahel: sedimentological and mineral‐magnetic analyses of lake sediments from Jikariya Lake, northeastern Nigeria

Wang

Holmes

Street-Perrott

et al. 2008

J Quaternary Science

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Previous studies have demonstrated long-term changes in effective moisture in subSaharan Africa. Here, we reconstruct Holocene environments using a $7 m lake-sediment sequence recovered from the northeastern Nigerian Sahel and attempt to distinguish basin-specific changes from regional climatic variations. The sequence was analysed for sedimentological properties, mineral magnetism and pollen, and dated by 137 Cs, 210 Pb excess and 14 C. Extremely arid conditions of the terminal Pleistocene ended ca. 11 500 cal. BP (calendar years) when climate ameliorated and a lake developed until the occurrence of an arid event leading to lake desiccation at $11 200 cal. BP. Following this, climate ameliorated and a water body re-emerged. Very wet conditions predominated 11 200-5600 cal. BP, followed by drought between 5600 and 5500 cal. BP and a return to moderate humidity from 5500 to 4000 cal. BP. After 4000 cal. BP, a marked deterioration occurred, culminating in lake desiccation at ca. 800 cal. BP. After this time the climate remained generally dry and the re-emerging lake was shallow. Comparison of these results with other well-dated sequences in the region demonstrates the importance of basin-specific influences on the palaeolimnological records in addition to regional climatic controls. Disentangling these different controls, as well as the reconstruction of Holocene climate, therefore requires a multiple-basin approach.

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Section: Introductionmentioning

confidence: 74%

“…11 500 cal. BP, whereas at nearby Bal Lake it took place up to 300 years earlier (Holmes et al, 1999a), although there are chronological uncertainties in the basal part of the Bal Lake record. At Kajemarum Oasis, the transition was even later than at Jikariya, around 10 800 cal.…”

Section: Discussionmentioning

confidence: 99%

Holocene environmental change in the West African Sahel: sedimentological and mineral‐magnetic analyses of lake sediments from Jikariya Lake, northeastern Nigeria

Wang

Holmes

Street-Perrott

et al. 2008

J Quaternary Science

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“…There is limited evidence for a wetter Sahara, which is also consistent with La Nin˜a conditions (e.g. Giannini et al, 2003), during Medieval times than in the following centuries (Holmes et al, 1999;Nicholson, 2000) (18). Further south, salinity proxies from which lake levels can be inferred indicate that lakes in equatorial East Africa were lower during the Medieval period suggesting drought (e.g.…”

Section: Africamentioning

confidence: 97%

Blueprints for Medieval hydroclimate

Seager

Graham

Herweijer

et al. 2007

Quaternary Science Reviews

179

150

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According to tree ring and other records, a series of severe droughts that lasted for decades afflicted western North America during the Medieval period resulting in a more arid climate than in subsequent centuries. A review of proxy evidence from around the world indicates that North American megadroughts were part of a global pattern of Medieval hydroclimate that was distinct from that of today. In particular, the Medieval hydroclimate was wet in northern South America, dry in mid-latitude South America, dry in eastern Africa but with strong Nile River floods and a strong Indian monsoon. This pattern is similar to that accompanying persistent North American droughts in the instrumental era. This pattern is compared to that associated with familiar climate phenomena. The best fit comes from a persistently La Nin˜a-like tropical Pacific and the warm phase of the so-called Atlantic Multidecadal Oscillation. A positive North Atlantic Oscillation (NAO) also helps to explain the Medieval hydroclimate pattern. Limited sea surface temperature reconstructions support the contention that the tropical Pacific was cold and the subtropical North Atlantic was warm, ideal conditions for North American drought. Tentative modeling results indicate that a multi-century La Nin˜a-like state could have arisen as a coupled atmosphere-ocean response to high irradiance and weak volcanism during the Medieval period and that this could in turn have induced a persistently positive NAO state. A La Nin˜a-like state could also induce a strengthening of the North Atlantic meridional overturning circulation, and hence warming of the North Atlantic Ocean, by (i) the ocean response to the positive NAO and by shifting the southern mid-latitude westerlies poleward which (ii) will increase the salt flux from the Indian Ocean into the South Atlantic and (iii) drive stronger Southern Ocean upwelling. r

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“…Chronological control is insufficient to evaluate the regional synchrony of these shifts (Holmes et al, 1999), but the LIA does not stand out as an exceptionally wet period at this site.…”

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confidence: 89%

“…Nevertheless, the most intense drought recorded in the Sr/Ca data, dated to c. 750-1000 CE, is also evident in the desiccation of neighbouring lakes (Holmes et al, 1999) and a large salinity increase at Bougdouma Oasis in Niger (Gasse and van Campo, 1994), suggesting a robust regional phenomenon.…”

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confidence: 96%

African hydroclimatic variability during the last 2000 years

Nash

Cort

Chase

et al. 2016

Quaternary Science Reviews

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The African continent is characterised by a wide range of hydroclimate regimes, ranging from humid equatorial West Africa to the arid deserts in the northern and southern subtropics. The livelihoods of much of its population are also vulnerable to future climate change, mainly through variability in rainfall affecting water resource availability. A growing number of data sources indicate that such hydroclimatic variability is an intrinsic component of Africa's natural environment. This paper, co-authored by members of the PAGES Africa 2k Working Group, presents an extensive assessment and discussion of proxy, historical and instrumental evidence for hydroclimatic variability across the African continent, spanning the last two millennia. While the African palaeoenvironmental record is characterised by spatially disjunctive datasets, with often less-than-optimal temporal resolution and chronological control, the available evidence allows the assessment of prominent spatial patterns of palaeomoisture variability through time. In this study, we focus sequentially on data for six major time windows: the first millennium AD, the Medieval Climate Anomaly (900-1250 CE), the Little Ice Age (1250-1750 CE), the end of the LIA (1750-1850 CE), the Early Modern Period , and the period of recent warming (1950 onwards). This results in a continentwide synthesis of regional moisture-balance trends through history, allowing consideration of possible driving mechanisms, and suggestions for future research.

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Late Holocene palaeolimnology of Bal Lake, Northern Nigeria, a multidisciplinary study

Cited by 41 publications

References 26 publications

Holocene environmental change in the West African Sahel: sedimentological and mineral‐magnetic analyses of lake sediments from Jikariya Lake, northeastern Nigeria

Holocene environmental change in the West African Sahel: sedimentological and mineral‐magnetic analyses of lake sediments from Jikariya Lake, northeastern Nigeria

Blueprints for Medieval hydroclimate

African hydroclimatic variability during the last 2000 years

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