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Hadley circulation and precipitation changes control black shale deposition in the Late Jurassic Boreal Seaway (2016)
Journal Article
Armstrong, H. A., Wagner, T., Herringshaw, L. G., Farnsworth, A. J., Lunt, D. J., Harland, M., …Atar, E. F. (2016). Hadley circulation and precipitation changes control black shale deposition in the Late Jurassic Boreal Seaway. Paleoceanography, 31(8), 1041-1053. https://doi.org/10.1002/2015pa002911

New climate simulations using the HadCM3L model with a paleogeography of the Late Jurassic [155.5 Ma], and proxy-data corroborate that warm and wet tropical-like conditions reached as far north as the UK sector of the Jurassic Boreal Seaway [~35oN].... Read More about Hadley circulation and precipitation changes control black shale deposition in the Late Jurassic Boreal Seaway.

Natural fractures in a United Kingdom shale reservoir analog, Cleveland Basin, northeast England (2014)
Journal Article
Imber, J., Armstrong, H., Clancy, S., Daniels, S., Herringshaw, L., McCaffrey, K., …Warren, C. (2014). Natural fractures in a United Kingdom shale reservoir analog, Cleveland Basin, northeast England. AAPG Bulletin, 98(11), 2411-2437. https://doi.org/10.1306/07141413144

Faults and fractures within the well-exposed Lower Jurassic Cleveland Ironstone and Whitby Mudstone formations may provide insights into the tectonic history of gas-prospective, Mississippian shale in northern England. Sub-vertical opening mode fract... Read More about Natural fractures in a United Kingdom shale reservoir analog, Cleveland Basin, northeast England.

An earth system approach to understanding the end-Ordovician (Hirnantian) mass extinction (2014)
Book Chapter
Armstrong, H., & Harper, D. (2014). An earth system approach to understanding the end-Ordovician (Hirnantian) mass extinction. In G. Keller, & A. Kerr (Eds.), Volcanism, impacts, and mass extinctions : causes and effects (287-300). Geological Society of America. https://doi.org/10.1130/2014.2505%2814%29

The Hirnantian mass extinction is recognized as the first of the "big three" extinctions and, along with the end-Permian and end-Cretaceous events, is the result of an acceleration in biotic extinctions concomitant with a rise in originations. The Hi... Read More about An earth system approach to understanding the end-Ordovician (Hirnantian) mass extinction.

Polar front shift and atmospheric CO2 during the glacial maximum of the Early Paleozoic Icehouse (2010)
Journal Article
Vandenbroucke, T., Armstrong, H., Williams, M., Paris, F., Zalasiewicz, J. A., Sabbe, K., …Servais, T. (2010). Polar front shift and atmospheric CO2 during the glacial maximum of the Early Paleozoic Icehouse. Proceedings of the National Academy of Sciences, 107(34), 14983-14986. https://doi.org/10.1073/pnas.1003220107

Our new data address the paradox of Late Ordovician glaciation under supposedly high pCO2 (8 to 22× PAL: preindustrial atmospheric level). The paleobiogeographical distribution of chitinozoan (“mixed layer”) marine zooplankton biotopes for the Hirnan... Read More about Polar front shift and atmospheric CO2 during the glacial maximum of the Early Paleozoic Icehouse.

Glaciation and deglaciation of the Libyan Desert: The Late Ordovician record (2010)
Journal Article
LeHeron, D., Armstrong, H., Wilson, C., Howard, J., & Gindre, L. (2010). Glaciation and deglaciation of the Libyan Desert: The Late Ordovician record. Sedimentary Geology, 223(1-2), 100-125. https://doi.org/10.1016/j.sedgeo.2009.11.002

Detailed outcrop studies at the flanks of Al Kufrah Basin, Libya, reveal the nature of glacially-related sedimentation and post-depositional deformation styles produced in association with the Late Ordovician glaciation, during which ice sheets expan... Read More about Glaciation and deglaciation of the Libyan Desert: The Late Ordovician record.

Response of the Inter-tropical Convergence Zone to Southern Hemisphere cooling during Upper Ordovician glaciation (2009)
Journal Article
Armstrong, H., Baldini, J., Challands, T., Gröcke, D., & Owen, A. (2009). Response of the Inter-tropical Convergence Zone to Southern Hemisphere cooling during Upper Ordovician glaciation. Palaeogeography, Palaeoclimatology, Palaeoecology, 284(3-4), 227-236. https://doi.org/10.1016/j.palaeo.2009.10.001

Stable isotope ratios of whole rock carbonates and faunas from three low latitude Upper Ordovician sections demonstrate a coherent pattern of shifting subtropical and tropical water masses and associated climate belts. We suggest that tropical water... Read More about Response of the Inter-tropical Convergence Zone to Southern Hemisphere cooling during Upper Ordovician glaciation.

Arabia-Eurasia collision and the forcing of mid-Cenozoic global cooling (2008)
Journal Article
Allen, M., & Armstrong, H. (2008). Arabia-Eurasia collision and the forcing of mid-Cenozoic global cooling. Palaeogeography, Palaeoclimatology, Palaeoecology, 265(1-2), 52-58. https://doi.org/10.1016/j.palaeo.2008.04.021

The end of the Eocene greenhouse world was the most dramatic phase in the long-term cooling trend of the Cenozoic Era. Here we show that the Arabia–Eurasia collision and the closure of the Tethys ocean gateway began in the Late Eocene at ~ 35 Ma, up... Read More about Arabia-Eurasia collision and the forcing of mid-Cenozoic global cooling.

Origin, sequence stratigraphy and depositional environment of an upper Ordovician (Hirnantian) deglacial black shale, Jordan (2005)
Journal Article
Armstrong, H. A., Turner, B. R., Makhlouf, I., Weedon, G., Williams, M., Al Smadi, A., & Abu Salah, A. (2005). Origin, sequence stratigraphy and depositional environment of an upper Ordovician (Hirnantian) deglacial black shale, Jordan. Palaeogeography, Palaeoclimatology, Palaeoecology, 220(3-4), 273-289. https://doi.org/10.1016/j.palaeo.2005.01.007

The upper Ordovician succession of Jordan was located 60°S, less than 100 km from the Hirnantian ice sheet margin. New graptolite dates indicate glaciation ended in Jordan in the late Hirnantian (persculptus Biozone). The succession records two glaci... Read More about Origin, sequence stratigraphy and depositional environment of an upper Ordovician (Hirnantian) deglacial black shale, Jordan.