Arctic Azolla study

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ARCTIC PALEOCENE EOCENE AZOLLA STUDY: NORTHERN ALASKA, CHUKCHI SEA AND THE CANADIAN BEAUFORT MACKENZIE BASIN

The Arctic Azolla study provides detailed data on the biostratigraphic, log and geochemical characteristics of the Eocene Azolla and PETM/EETM intervals in more than 50 northern Alaskan, Chukchi Sea and Canadian Beaufort well, plus cores recovered by the 2004 Arctic Coring Expedition (ACEX).

Alaska Azolla wellsBMB Azolla wellsQuantitative palynological analysis confirms that both intervals are well-developed across the region. Gamma logs show a strong increase in both intervals, reflecting relatively high total organic carbon and their potential as petroleum source rocks.

Geochemical analysis was subcontracted to Humble Geochemical Services Division (HGSD), Texas, with initial screening to determine percent Total Organic Carbon (%TOC). Samples with TOC equal to or greater than 0.5% were then subjected to Rock-Eval pyrolysis to determine their source rock potential and maturity.

Click on the arrow below for a list of the report contents.

REPORT CONTENTS

VOLUME 1. OVERVIEW AND SYNTHESIS OF RESULTS

1. INTRODUCTION

1.1 Background to the study

1.2 The Arctic Coring Expedition (ACEX)

1.3 Stratigraphy of the Azolla and Apectodinium acme events

1.4 The Apectodinium acme event and the Paleocene Eocene Thermal maximum (PETM)

1.5 The Azolla acme event: implications for greenhouse to icehouse climate change and petroleum generation

2. THE STUDY

2.1 Outline of the Study

2.2 Selection of wells and intervals

2.3 Sample collection

3. WELL DATABASE

3.1 Chukchi Sea

3.2 Northern Alaska

3.3 Canadian Beaufort Mackenzie basin (BMB)

4. STRATIGRAPHY

4.1 Methodology

4.2 Age and zonal assignment

4.3 Sequences based on gamma logs

4.4 The Terminal Eocene Event and the Terminal Eocene Unconformity

5. PRESENTATION OF STRATIGRAPHIC DATA

5.1 Alaskan correlation diagrams

5.2 Canadian BMB correlation diagrams

5.3 Tabulation of sequence and zonal picks

5.4 Range charts

6. GEOCHEMISTRY: METHODOLOGY AND APPROACH

6.1 Sample analysis

6.2 Alaskan and Canadian BMB data

6.3 ACEX data

7. RESULTS

VOLUMES 2 to 11

VOLUME 2. Northern Alaska and Chukchi Sea correlation diagrams

VOLUME 3. Canadian Beaufort Mackenzie Basin correlation diagrams

VOLUMES 4-7. Northern Alaska, Chukchi Sea and Canadian Beaufort Mackenzie Basin wells. Excel and Stratabugs range charts of palynological zonal markers: wells A to L (see well listing below)

VOLUMES 8-9. Geochemistry plots, northern Alaskan, Chukchi, Canadian wells and ACEX wells, including the following plots:

  • TOC and RockEval data.
  • Geochemical log of TOC, remaining potential (S2), kerogen type (HI), normalized oil content, and calculated and measured vitrinite reflectance.
  • Kerogen quality.
  • Kerogen type.
  • Kerogen type and maturity (Tmax).
  • Kerogen type and maturity (Tmax calculated %VRo).
  • Kerogen conversion and maturity (based on Tmax).
  • Kerogen conversion and maturity (calculated %VRo from Tmax).

VOLUME 10. Tabulation of biostratigraphic and geochemical data: Northern Alaska and Chukchi Sea

VOLUME 11. Tabulation of biostratigraphic and geochemical data: Canadian Beaufort Mackenzie Basin


EXAMPLE PLOTS OF GEOCHEMICAL ANALYSES

percent TOC

oxygen indexhydrogen index

 

2008 AZOLLA STUDY UPDATE

The 2008 update provides the following new information on the Azolla interval:

1. Evidence for sea-surface temperatures (SST) during deposition of the Azolla interval.

2. The duration of the Arctic  Azolla event, based on the age of the top of the interval, which was not recovered by the ACEX cores, but which occurs in the Alaskan Aurora 1 and Mount Elbert wells.

3. Maturation and development of the Azolla and PETM intervals offshore into the Canada Basin, based on seismic and geothermal modelling

 


 

Example figure from the 2008 Azolla study update, courtesy of D. Houseknecht (US Geological Survey), showing some of the results of his geothermal modelling from the Alaskan Aurora 1 well northwards into the Canada basin.

2008 example figurePlease contact Dr Jonathan Bujak for further details.

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