University of Hertfordshire Research Archive

        JavaScript is disabled for your browser. Some features of this site may not work without it.

        Browse

        All of UHRABy Issue DateAuthorsTitlesThis CollectionBy Issue DateAuthorsTitles

        Arkivum Files

        My Downloads
        View Item 
        • UHRA Home
        • University of Hertfordshire
        • PhD Theses Collection
        • View Item
        • UHRA Home
        • University of Hertfordshire
        • PhD Theses Collection
        • View Item

        Middle Pleistocene Till Lithostratigraphy in South Bedfordshire and the Hitchin Gap

        View/Open
        Download fulltext (PDF, 23Kb)
        Download fulltext (PDF, 81Kb)
        Download fulltext (PDF, 263Kb)
        Download fulltext (PDF, 993Kb)
        Download fulltext (PDF, 1Mb)
        Download fulltext (PDF, 439Kb)
        Download fulltext (PDF, 4Mb)
        Download fulltext (PDF, 1Mb)
        Download fulltext (PDF, 3Mb)
        Download fulltext (PDF, 1Mb)
        Download fulltext (PDF, 993Kb)
        Download fulltext (PDF, 52Kb)
        Download fulltext (PDF, 111Kb)
        Download fulltext (PDF, 145Kb)
        Author
        Brownsell, Wendy Joan
        Attention
        2299/3762
        Abstract
        A revised lithostratigraphy and glacial history of north Hertfordshire and south Bedfordshire is based upon detailed textural data in the clay to fine gravel fraction, carbonate content, small clast lithological data and macrofabrics, derived from laboratory and field analyses of tills from 30 sites. These include four deep boreholes sunk within the Hitchin Gap. A range of statistical procedures was used, including multivariate analysis of the petrographic properties, enabling the identification of tills from two separate incursions into the Gap. A further till-type was identified in south Bedfordshire indicating an ice advance from the northwest/NNW extending at least as far east as Milton Bryan. Statistical comparison with tills in the neighbouring Vale of St. Albans suggested the presence of the Ware Member till within the Gap. Two hypotheses are suggested to explain variations in lithological content of tills north of the Chalk scarp. The first envisages ice entering the study area along the different trajectories suggested by Fish and Whiteman (2001). During the early part of the glaciation, ice reaching the west of the study area would approach from the north, crossing a shorter distance over Chalk bedrock and collecting less chalk and flint than ice moving into the eastern part of the study area. The second hypothesis invokes an incursion of ice from a northwest - NNW direction into the west of the study area, depositing a chalk-free till. This is subsequently assimilated by ice from the northeast, resulting in the final deposition of a homogeneous mixture of debris from the two advances, with a lower chalk content than tills found to the east. The outcome of either of these scenarios is a till with a low acid-soluble content and low flint/quartz ratio in the west of the study area, as found during this work. Within the Hitchin Gap, a lobe of ice, probably an early part of the northeasterly advance, deposited a lower till. This is considered to be earlier than the Ware Member till and has more variable lithological characteristics and a finer matrix that the higher tills. The latter are mainly melt-out, flow or slumped tills with occasional instances of lodgement and deformation. They represent in situ wasting of dead ice within the Gap. Surface tills in the Gap form a continuum with tills to the north and comprise mainly deformation tills, deposited by the final northeasterly re-advance of ice responsible for widespread coverage of the region, with the exception of the Chiltern Hills southwest of Hitchin. No evidence is found of more than one lithostratigraphic unit of till outside the Hitchin Gap.
        Publication date
        2009-08-05
        Other links
        http://hdl.handle.net/2299/3762
        Metadata
        Show full item record
        Keep in touch

        © 2019 University of Hertfordshire

        I want to...

        • Apply for a course
        • Download a Prospectus
        • Find a job at the University
        • Make a complaint
        • Contact the Press Office

        Go to...

        • Accommodation booking
        • Your student record
        • Bayfordbury
        • KASPAR
        • UH Arts

        The small print

        • Terms of use
        • Privacy and cookies
        • Criminal Finances Act 2017
        • Modern Slavery Act 2015
        • Sitemap

        Find/Contact us

        • T: +44 (0)1707 284000
        • E: ask@herts.ac.uk
        • Where to find us
        • Parking
        • hr
        • qaa
        • stonewall
        • AMBA
        • ECU Race Charter
        • disability confident
        • AthenaSwan