Refining palaeoenvironmental analysis using integrated quantitative granulometry and palynology

Stephen Stukins,Duncan Mcilroy,David W Jolley

doi:10.1144/petgeo2016-073

Stephen Stukins, Duncan Mcilroy + Show 1 more

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https://doi.org/10.1144/petgeo2016-073

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Abstract

Accurate palaeoenvironmental analysis is at the heart of producing reliable interpretations and depositional models. This study demonstrates a multivariate statistical approach to facies analysis based on relationships between grain size and quantitative palynology. Our methodology has the advantage that it can be used on small amounts of sample, such as core or well cuttings, as the basis for facies analysis. Proof of concept studies involving the collection of grain-size and palynological datasets from well-exposed outcrops of the Middle Jurassic, Lajas Formation of the Neuquén Basin, Argentina, demonstrate that canonical correspondence analysis can be used to consistently recognize facies and aid in the determination of depositional environments. This study demonstrates the link between depositional facies, grain-size distribution, palynomorph hydrodynamics and assemblage taphonomy of palynomorphs. This knowledge can be transferred into a semi-automated statistical facies prediction technique for the subsurface in complex depositional settings, particularly when calibrated against conventional sedimentary facies analysis. Supplementary material: The full set of grain-size data and statistical scores are available at: https://doi.org/10.6084/m9.figshare.c.3745481.v1

Highlights

Palaeoenvironmental interpretation is at the core of effective reservoir characterization and sequence stratigraphic analysis
Detailed in this study is the analysis of two primary datasets that can be obtained from well cuttings from a well-documented outcrop framework (Brandsæter et al 2005; McIlroy et al 2005; McIlroy et al 1999)
Significant advances in the understanding of tide-dominated deltas have been made in recent years through study of the Lajas Formation of the Neuquén Basin in Argentina (McIlroy et al 2005; McIlroy 2007; McIlroy 2004; Martinius et al 2000; Ichaso & Dalrymple 2009; Brandsæter et al 2005; Rossi & Steel 2016)

Summary

Introduction

Palaeoenvironmental interpretation is at the core of effective reservoir characterization and sequence stratigraphic analysis. Significant advances in the understanding of tide-dominated deltas have been made in recent years through study of the Lajas Formation of the Neuquén Basin in Argentina (McIlroy et al 2005; McIlroy 2007; McIlroy 2004; Martinius et al 2000; Ichaso & Dalrymple 2009; Brandsæter et al 2005; Rossi & Steel 2016). Facies characterization and palaeoenvironmental interpretation is notoriously difficult in tide-influenced deltaic deposits, requiring the full breadth of palaeontological and sedimentological tools to be applied (Martinius et al 2011; van Cappelle 2016). The linkage between the palynology and palaeoenvironment of the hinterland floras, and its application to the understanding of the coastal depositional system has been investigated previously (Stukins et al 2013)

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