Geostatiscal Analysis of Meandering Processes and Channel Migration: Case Study of Modern Analogues for the Long Nab Member, Scalby Formation, Yorkshire, UK

Abstract

The processes pertaining to meandering rivers are moderated by the interaction between flow behaviour, bank erosion, and sedimentation. These processes generate a complex and heterogeneous channel geometry and deposition in the meandering river system. Re-examination of the Long Nab member in the Scalby Formation of the Ravenscar Group (Yorkshire, UK) integrates field-based interpretations (i.e. depositional architecture, paleoflow patterns, geometry and erosional surfaces) and geostatistical analysis from selected modern analogues. Hence these modern analogues encompass the predominant fluvial outcrop of Long Nab member. The methodology used in this study is based on geostatistical attributes extracted from these analogous, meandering rivers that exemplify both the confined and non-confined meandering point bars deposits and morphodynamics of Long Nab member. The parameters derived from the modern systems are channel width B_m, amplitude a_m, radius of curvature r_c, sinuosity s_i, wavelength λ_m, meander width ratio MWR, meander length ratio MLR, channel length L and migration rate M_r. Comprehensive attribute measurements were carried out across the studied sections by using high resolution satellite imagery datasets collected from four case-studies, with a total number of 3170 measurements of recent imagery and 1390 measurements collected from available historical imagery. The geostatistical data derived from the modern analogues is multi-dimensional in nature, making analysis difficult. We apply data mining techniques such as parallel coordinates to investigate and identify the important relationships within the modern analogues data. Implications of channel migration rate and structure were also elucidated in this paper. This study addresses the distinct advantage of the utilisation of the Landsat imagery, which can be used to improve understanding of the river morphodynamics, planform architecture and stratigraphic signature of different fluvial processes and features. Additionally, forward modelling studies can be applied using the averaged geostatiscal values, aiming to generate object oriented channel model.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018