Palaeoecology of syn-rift topography: A Late Jurassic footwall island on the Josephine Ridge, Central Graben, North Sea

Adam D. McArthur; David W. Jolley; Adrian J. Hartley; Stuart G. Archer; Hugo M. Lawrence

doi:10.1016/j.palaeo.2016.06.033

Palaeoecology of syn-rift topography: A Late Jurassic footwall island on the Josephine Ridge, Central Graben, North Sea

Adam D. McArthur, David W. Jolley, Adrian J. Hartley, Stuart G. Archer, Hugo M. Lawrence

ConocoPhillips UK Ltd

Research output: Contribution to journal › Article › peer-review

14 Citations (Scopus)

19 Downloads (Pure)

Abstract

Understanding rift topography is essential for determining source areas, sediment pathways, and the type of sediment delivered to a rift basin; factors essential for interpreting petroleum systems in ancient rifts. Here we investigate Upper Jurassic sediments from the Josephine Ridge region of the Central Graben, North Sea, by integrating geophysical, palynological, petrophysical and sedimentological datasets to analyse the palaeoenvironments of the Jade and Judy horsts, the tops of which are not preserved. Interpretation of geophysical and petrophysical data together with core descriptions show study wells to step progressively away from the Josephine Ridge into adjacent grabens. One hundred and five palynological samples from six wells range from the Oxfordian to the Lower Tithonian, spanning the syn-rift period of the Central Graben. Samples from the adjacent grabens and the Jade Horst are rich in dinoflagellate cysts and possess <20% terrestrial palynomorphs. Samples from the Judy Horst contain a wide range of terrestrial palynomorphs, dominated by lycopsid, fern and moss spores, representing c.50% of the recovered palynomorphs. Correspondence analysis of the assemblages imply Jade did not possess a terrestrial ecosystem; Judy samples define seven groupings of related miospores, all interpreted to represent very low lying, relatively early successional type environments. This implies subaerial exposure of the Judy Horst during the Late Jurassic, which is interpreted to have formed an isolated, low relief, footwall crest island. This study provides a new methodology for investigating rift topography, particularly in cases where the tops of horsts were subsequently removed by erosion. The Judy Island would have separated the Central Graben into its eastern and western arms earlier than previously predicted, in the Late Oxfordian, with consequences for distribution of shallow and deep-marine reservoir quality sediments.

Original language	English
Pages (from-to)	63-75
Number of pages	13
Journal	Palaeogeography Palaeoclimatology Palaeoecology
Volume	459
Early online date	25 Jun 2016
DOIs	https://doi.org/10.1016/j.palaeo.2016.06.033
Publication status	Published - 1 Oct 2016

Bibliographical note

We thank ConocoPhillips (U.K.) Limited for providing the study data and financial support, along with co-ventures in the study area BG Group, ENI UK Ltd., Chevron and OMV UK Ltd. for permission to release data. Nick Schofield, Ben Kilhams and Rob Daly are thanked for the discussions, and Fiona Thompson for laboratory assistance. Two anonymous reviewers and Editor David Bottjer are thanked for their comments.

Keywords

palynology
Horst palaeoecology
Upper Jurassic
Central North Sea
source-to-sink

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1016/j.palaeo.2016.06.033Licence: Unspecified

Accepted Manuscript
© 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Accepted author manuscript, 2.93 MBLicence: CC BY-NC-ND

David Jolley
- School of Geosciences, Geology and Geophysics - Chair in Geology
Person: Academic

Cite this

@article{45512f3610b84eb8b3736f9782924695,

title = "Palaeoecology of syn-rift topography: A Late Jurassic footwall island on the Josephine Ridge, Central Graben, North Sea",

abstract = "Understanding rift topography is essential for determining source areas, sediment pathways, and the type of sediment delivered to a rift basin; factors essential for interpreting petroleum systems in ancient rifts. Here we investigate Upper Jurassic sediments from the Josephine Ridge region of the Central Graben, North Sea, by integrating geophysical, palynological, petrophysical and sedimentological datasets to analyse the palaeoenvironments of the Jade and Judy horsts, the tops of which are not preserved. Interpretation of geophysical and petrophysical data together with core descriptions show study wells to step progressively away from the Josephine Ridge into adjacent grabens. One hundred and five palynological samples from six wells range from the Oxfordian to the Lower Tithonian, spanning the syn-rift period of the Central Graben. Samples from the adjacent grabens and the Jade Horst are rich in dinoflagellate cysts and possess <20% terrestrial palynomorphs. Samples from the Judy Horst contain a wide range of terrestrial palynomorphs, dominated by lycopsid, fern and moss spores, representing c.50% of the recovered palynomorphs. Correspondence analysis of the assemblages imply Jade did not possess a terrestrial ecosystem; Judy samples define seven groupings of related miospores, all interpreted to represent very low lying, relatively early successional type environments. This implies subaerial exposure of the Judy Horst during the Late Jurassic, which is interpreted to have formed an isolated, low relief, footwall crest island. This study provides a new methodology for investigating rift topography, particularly in cases where the tops of horsts were subsequently removed by erosion. The Judy Island would have separated the Central Graben into its eastern and western arms earlier than previously predicted, in the Late Oxfordian, with consequences for distribution of shallow and deep-marine reservoir quality sediments. ",

keywords = "palynology, Horst palaeoecology, Upper Jurassic, Central North Sea, source-to-sink",

author = "McArthur, {Adam D.} and Jolley, {David W.} and Hartley, {Adrian J.} and Archer, {Stuart G.} and Lawrence, {Hugo M.}",

note = "We thank ConocoPhillips (U.K.) Limited for providing the study data and financial support, along with co-ventures in the study area BG Group, ENI UK Ltd., Chevron and OMV UK Ltd. for permission to release data. Nick Schofield, Ben Kilhams and Rob Daly are thanked for the discussions, and Fiona Thompson for laboratory assistance. Two anonymous reviewers and Editor David Bottjer are thanked for their comments.",

year = "2016",

month = oct,

day = "1",

doi = "10.1016/j.palaeo.2016.06.033",

language = "English",

volume = "459",

pages = "63--75",

journal = "Palaeogeography Palaeoclimatology Palaeoecology",

issn = "0031-0182",

publisher = "Elsevier",

}

TY - JOUR

T1 - Palaeoecology of syn-rift topography

T2 - A Late Jurassic footwall island on the Josephine Ridge, Central Graben, North Sea

AU - McArthur, Adam D.

AU - Jolley, David W.

AU - Hartley, Adrian J.

AU - Archer, Stuart G.

AU - Lawrence, Hugo M.

N1 - We thank ConocoPhillips (U.K.) Limited for providing the study data and financial support, along with co-ventures in the study area BG Group, ENI UK Ltd., Chevron and OMV UK Ltd. for permission to release data. Nick Schofield, Ben Kilhams and Rob Daly are thanked for the discussions, and Fiona Thompson for laboratory assistance. Two anonymous reviewers and Editor David Bottjer are thanked for their comments.

PY - 2016/10/1

Y1 - 2016/10/1

N2 - Understanding rift topography is essential for determining source areas, sediment pathways, and the type of sediment delivered to a rift basin; factors essential for interpreting petroleum systems in ancient rifts. Here we investigate Upper Jurassic sediments from the Josephine Ridge region of the Central Graben, North Sea, by integrating geophysical, palynological, petrophysical and sedimentological datasets to analyse the palaeoenvironments of the Jade and Judy horsts, the tops of which are not preserved. Interpretation of geophysical and petrophysical data together with core descriptions show study wells to step progressively away from the Josephine Ridge into adjacent grabens. One hundred and five palynological samples from six wells range from the Oxfordian to the Lower Tithonian, spanning the syn-rift period of the Central Graben. Samples from the adjacent grabens and the Jade Horst are rich in dinoflagellate cysts and possess <20% terrestrial palynomorphs. Samples from the Judy Horst contain a wide range of terrestrial palynomorphs, dominated by lycopsid, fern and moss spores, representing c.50% of the recovered palynomorphs. Correspondence analysis of the assemblages imply Jade did not possess a terrestrial ecosystem; Judy samples define seven groupings of related miospores, all interpreted to represent very low lying, relatively early successional type environments. This implies subaerial exposure of the Judy Horst during the Late Jurassic, which is interpreted to have formed an isolated, low relief, footwall crest island. This study provides a new methodology for investigating rift topography, particularly in cases where the tops of horsts were subsequently removed by erosion. The Judy Island would have separated the Central Graben into its eastern and western arms earlier than previously predicted, in the Late Oxfordian, with consequences for distribution of shallow and deep-marine reservoir quality sediments.

AB - Understanding rift topography is essential for determining source areas, sediment pathways, and the type of sediment delivered to a rift basin; factors essential for interpreting petroleum systems in ancient rifts. Here we investigate Upper Jurassic sediments from the Josephine Ridge region of the Central Graben, North Sea, by integrating geophysical, palynological, petrophysical and sedimentological datasets to analyse the palaeoenvironments of the Jade and Judy horsts, the tops of which are not preserved. Interpretation of geophysical and petrophysical data together with core descriptions show study wells to step progressively away from the Josephine Ridge into adjacent grabens. One hundred and five palynological samples from six wells range from the Oxfordian to the Lower Tithonian, spanning the syn-rift period of the Central Graben. Samples from the adjacent grabens and the Jade Horst are rich in dinoflagellate cysts and possess <20% terrestrial palynomorphs. Samples from the Judy Horst contain a wide range of terrestrial palynomorphs, dominated by lycopsid, fern and moss spores, representing c.50% of the recovered palynomorphs. Correspondence analysis of the assemblages imply Jade did not possess a terrestrial ecosystem; Judy samples define seven groupings of related miospores, all interpreted to represent very low lying, relatively early successional type environments. This implies subaerial exposure of the Judy Horst during the Late Jurassic, which is interpreted to have formed an isolated, low relief, footwall crest island. This study provides a new methodology for investigating rift topography, particularly in cases where the tops of horsts were subsequently removed by erosion. The Judy Island would have separated the Central Graben into its eastern and western arms earlier than previously predicted, in the Late Oxfordian, with consequences for distribution of shallow and deep-marine reservoir quality sediments.

KW - palynology

KW - Horst palaeoecology

KW - Upper Jurassic

KW - Central North Sea

KW - source-to-sink

U2 - 10.1016/j.palaeo.2016.06.033

DO - 10.1016/j.palaeo.2016.06.033

M3 - Article

SN - 0031-0182

VL - 459

SP - 63

EP - 75

JO - Palaeogeography Palaeoclimatology Palaeoecology

JF - Palaeogeography Palaeoclimatology Palaeoecology

ER -

Palaeoecology of syn-rift topography: A Late Jurassic footwall island on the Josephine Ridge, Central Graben, North Sea

Abstract

Bibliographical note

Keywords

UN SDGs

Access to Document

Fingerprint

Profiles

David Jolley

Cite this