Abstract
The early Marsdenian substage (Millstone Grit Group) of the Pennines comprises repeated deltaic cycles separated by ammonoid-bearing marine bands. This cyclicity, controlled by the combined forces of glacio-eustasy and modulations in sediment supply, provides an important outcrop area for the application of sequence stratigraphic principles.
A new correlation framework is presented where two orders of sequence are identified: – (1) a low-order sequence, within which marine bands (R2a1, R2b1, R2b2 and R2b3) represent a maximum flooding surface, and (2) high-order sequences nested within the low-order sequences. By integrating and correlating key exposures, historic well boreholes and field mapping, lateral changes in facies and facies association are observed, and palaeogeographic trends mapped. This allows the variation in sequence and systems tract stacking patterns to be interpreted. Three orders of Milankovitch cyclicity are inferred to control the sequence stacking patterns; long-duration (∼400ka) eccentricity oscillation controlling maximum flooding events represented by the R2a1 and R2b2 marine bands, sub-100ka obliquity oscillations (controlling the R2b1, R2b2 and R2b3 marine bands and intervening low-order sequence boundaries), and precessional frequencies (∼25ka) which may control the periodicity of the high-order sequences.
A new correlation framework is presented where two orders of sequence are identified: – (1) a low-order sequence, within which marine bands (R2a1, R2b1, R2b2 and R2b3) represent a maximum flooding surface, and (2) high-order sequences nested within the low-order sequences. By integrating and correlating key exposures, historic well boreholes and field mapping, lateral changes in facies and facies association are observed, and palaeogeographic trends mapped. This allows the variation in sequence and systems tract stacking patterns to be interpreted. Three orders of Milankovitch cyclicity are inferred to control the sequence stacking patterns; long-duration (∼400ka) eccentricity oscillation controlling maximum flooding events represented by the R2a1 and R2b2 marine bands, sub-100ka obliquity oscillations (controlling the R2b1, R2b2 and R2b3 marine bands and intervening low-order sequence boundaries), and precessional frequencies (∼25ka) which may control the periodicity of the high-order sequences.
| Original language | English |
|---|---|
| Article number | pygs2021-014 |
| Number of pages | 41 |
| Journal | Proceedings Of The Yorkshire Geological Society |
| Volume | 64 |
| Issue number | 3-4 |
| Early online date | 7 Feb 2023 |
| DOIs | |
| Publication status | Published - Nov 2023 |
Bibliographical note
AcknowledgementsThe authors would like to thank Rhodri Jerrett and Ole Martinsen for reviewing this paper. This paper is dedicated to Trevor Elliott (supervisor of the project).
Funding
The work presented here was completed as part of a joint BGS/University of Liverpool funded PhD project (1997–2001)
Data Availability Statement
The data that support the findings of this study are available from the principal author upon reasonable request.Keywords
- Palaeoenvironment
- Petroleum Geoscience and Geoenergy
- Sedimentology
- Stratigraphy
