ORCID Profile
0000-0002-7641-5857
Current Organisation
University of Brighton
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Publisher: Wiley
Date: 23-09-2004
DOI: 10.1002/ESP.1138
Publisher: Springer Science and Business Media LLC
Date: 21-04-2013
DOI: 10.1038/NGEO1797
Publisher: Wiley
Date: 14-08-2019
DOI: 10.1002/ESP.4704
Publisher: Springer Science and Business Media LLC
Date: 23-06-2023
DOI: 10.1038/S41597-023-02303-Y
Abstract: Documentary climate data describe evidence of past climate arising from predominantly written historical documents such as diaries, chronicles, newspapers, or logbooks. Over the past decades, historians and climatologists have generated numerous document-based time series of local and regional climates. However, a global dataset of documentary climate time series has never been compiled, and documentary data are rarely used in large-scale climate reconstructions. Here, we present the first global multi-variable collection of documentary climate records. The dataset DOCU-CLIM comprises 621 time series (both published and hitherto unpublished) providing information on historical variations in temperature, precipitation, and wind regime. The series are evaluated by formulating proxy forward models (i.e., predicting the documentary observations from climate fields) in an overlapping period. Results show strong correlations, particularly for the temperature-sensitive series. Correlations are somewhat lower for precipitation-sensitive series. Overall, we ascribe considerable potential to documentary records as climate data, especially in regions and seasons not well represented by early instrumental data and palaeoclimate proxies.
Publisher: Springer Science and Business Media LLC
Date: 11-07-2017
Abstract: Reproducible climate reconstructions of the Common Era (1 CE to present) are key to placing industrial-era warming into the context of natural climatic variability. Here we present a community-sourced database of temperature-sensitive proxy records from the PAGES2k initiative. The database gathers 692 records from 648 locations, including all continental regions and major ocean basins. The records are from trees, ice, sediment, corals, speleothems, documentary evidence, and other archives. They range in length from 50 to 2000 years, with a median of 547 years, while temporal resolution ranges from biweekly to centennial. Nearly half of the proxy time series are significantly correlated with HadCRUT4.2 surface temperature over the period 1850–2014. Global temperature composites show a remarkable degree of coherence between high- and low-resolution archives, with broadly similar patterns across archive types, terrestrial versus marine locations, and screening criteria. The database is suited to investigations of global and regional temperature variability over the Common Era, and is shared in the Linked Paleo Data (LiPD) format, including serializations in Matlab, R and Python.
Publisher: Wiley
Date: 13-09-2020
DOI: 10.1002/ESP.4976
Abstract: A synthesis of the geochemistry of silcretes and their host sediments in the Kalahari Desert and Cape coastal zone, using isocon comparisons, shows that silcretes in the two regions are very different. Kalahari Desert silcretes outcrop along drainage‐lines and within pans, and formed by groundwater silicification of near‐surface Kalahari Group sands. Silicification was approximately isovolumetric. Few elements were lost silicon (Si) and potassium (K) were gained as microquartz precipitated in the sediment porosity and glauconite formed in the sub‐oxic groundwater conditions. The low titanium (Ti) content reflects the composition of the host sands. Additional elements in the Kalahari Desert silcretes were supplied in river water and derived from weathering of silicates in basement rocks. Evaporation under an arid climate produced high‐pH groundwater that mobilized and precipitated Si this process is still occurring. In the Cape coastal zone, pedogenic silcretes cap hills and plateaus, overlying deeply weathered argillaceous bedrock. Silicification resulted from intensive weathering that destroyed the bedrock silicates, almost completely removing most elements and causing a substantial volume decrease. Some of the silica released formed a microcrystalline quartz matrix, and most Ti precipitated as anatase, so the Cape silcretes contain relatively high Ti levels. The intense weathering that formed the Cape silcretes could have occurred in the Eocene, during and after the Palaeocene‐Eocene Thermal Maximum, when more acidic rainfall and high temperatures resulted in intensified silicate weathering worldwide. This could have been responsible for widespread formation of pedogenic silcretes elsewhere in Africa and around the globe. Trace element sourcing of silcrete artefacts to particular outcrops has most potential in the Cape, where differences between separate bedrock areas are reflected in the silcrete composition. In the Kalahari Desert, gains of some elements can override compositional differences of the parent material, and sourcing should be based on elements that show the least change during silicification. © 2020 John Wiley & Sons, Ltd.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for David Nash.