The Warder Formation of Ngaterian (late AlbianCenomanian) age crops out in southern Marlborough, New Zealand. Outcrops are characterised by fining-upward alluvial cycles deposited by easterly flowing rivers on a coastal plain. Within-channel deposits include clast-supported conglomerate and trough cross-bedded sandstone, overlain by alternating sandstone and siltstone, lateral accretion (inclined heterolithic stratification) beds, in turn overlain by siltstone and claystone. The fine-grained units are interpreted as lacustrine sediments deposited in ox-bow lakes through meander loop cut-off. All outcrops are fault bounded, so a complete pattern of fluvial reconstruction cannot be made. The rivers which deposited the Warder Formation had a mean sinuosity of 1.5 and a discharge of 72-102 m 3 /s. Sedimentation was terminated by the eruption of alkaline basalts related to regional sea-floor spreading.

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