Mineralogical proxies of a Pliocene maar lake recording changes in precipitation at the Camp dels Ninots (Pliocene, NE Iberia)

Abstract. The accurate and precise reconstruction of Quaternary climate as well as the events that punctuate it is an important driver of the study of lake sediment archives. However, until recently lake sediment-based palaeoclimate reconstructions have largely concentrated on Northern Hemisphere lake sequences due to a scarcity of continuous and high-resolution lake sediment sequences from the Southern Hemisphere, especially from the southern mid-latitudes. In this context, the deep maar lakes of the Auckland Volcanic Field of northern New Zealand are significant as several contain continuous and well-laminated sediment sequences. Onepoto Basin potentially contains the longest temporal lake sediment record from the Auckland Volcanic Field (AVF), spanning from Marine Isotope Stage 6e (MIS 6e) to the early Holocene when lacustrine sedimentation was terminated by marine breach of the south-western crater tuff ring associated with post-glacial sea-level rise. The Onepoto record consists of two new, overlapping cores spanning ca. 73 m combined with archive material in a complete composite stratigraphy. Tephrochronology and 14C dating provide the fundamental chronological framework for the core, with magnetic relative palaeo-intensity variability downcore, and meteoric 10Be influx into the palaeolake to refine the chronology. The µ-XRF (micro X-ray fluorescence) downcore variability for the entirety of the lake sediment sequence has been established with measurement of a range of proxies for climate currently underway. This work will produce the first continuous record of the last 200 kyr of palaeoclimate from northern New Zealand to date.

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Holocene Environments in Northeast Africa

The Oxford Handbook of Ancient Nubia ◽

10.1093/oxfordhb/9780190496272.013.4 ◽

2021 ◽

pp. 62-78

Author(s):

Martin Williams

Keyword(s):

Late Holocene ◽

Flood Plain ◽

Low Flow ◽

Archaeological Record ◽

Human Occupation ◽

Complex Interactions ◽

Maar Lake ◽

Low Levels ◽

White Nile ◽

Ne Africa

This chapter provides an overview of the geography, hydrology, and climate of NE Africa, with particular reference to the complex interactions between river regime, climate, the biota, and human settlement. During the Early (11.7–8.2 ka) and Middle Holocene (8.2–4.2 ka) the climate was far less arid than today across the Nile basin, including Nubia, albeit with sporadic dry phases. Climatic desiccation set in during the Late Holocene (4.2 ka to present), with minor wet phases. Intervals when the Nile flow regime was apparently shifting from high to low flow and flood plain incision have provisional ages of ca. 8.15–7.75 ka, 6.4–6.15 ka, 5.7–5.45 ka, 4.7–4.25 ka, 3.35–2.9 ka, 2.8–2.55 ka, and 1600 ce. In the Kerma area of Nubia there were two periods of relatively dense human occupation in the earlier part of the Holocene from 10 ka to 8 ka and from 7 ka to 6 ka, with two significant gaps in the archaeological record at 7.5–7.1 ka and 6.0–5.4 ka, that coincided with very low levels in Lake Challa, a maar lake on the eastern flank of Mt Kilimanjaro, near the Ugandan headwaters of the White Nile.

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