Madeleine L. Vickers

Umeå University | UMU · Department of Ecology and Environmental Science

A causal mechanism for the Volgian Isotopic Carbon Excursion (VOICE) remains enigmatic. Elemental geochemical profiles of the Deer Bay Formation, Sverdrup Basin, Arctic Canada that record the VOICE and contemporaneous strata are herein examined to provide insight into depositional environments during Late Jurassic‐Early Cretaceous time. Silver (Ag)...

Lower Cretaceous stratigraphy of the high palaeo-latitude Arctic-Boreal Realm is generally more poorly understood than its lower-latitude Tethyan counterpart, prohibiting regional correlations and evaluation of global climate dynamics during this important high- p CO 2 period. In this paper, a holostratigraphic scheme and lithostratigraphic revisio...

The Lower Cretaceous succession of Svalbard is known to contain numerous glendonites, particularly in intervals of Hauterivian–Barremian and late Aptian age (e.g., Vickers et al., 2019). These are reported as ranging from centimeter to decimeter-scale in size (Vickers et al., 2018), which is within the usual size range for ancient glendonites and m...

The International Ocean Discovery Program (IODP) Expedition 396 to the mid-Norwegian margin recovered > 1300 m of pristinely preserved, volcanic-ash-rich sediments deposited during the late Paleocene and early Eocene from close to the centre of the North Atlantic Igneous Province (NAIP). Remarkably, many of these cores contain glendonites, pseudomo...

Glendonites are stellate nodules, pseudomorphs after cold-water ikaite, a carbonate mineral that is found today in nature only growing under conditions of near-freezing temperatures and unusual chemistry. Glendonites are found in sedimentary successions throughout the geological record and have come to be regarded as climatic and/or paleoenvironmen...

The type locality for the upper Oligocene Nuwok Member of the Sagavanirktok Formation (Carter Creek, North Slope, Alaska, USA) contains abundant occurrence of glendonite, a pseudomorph after the calcium carbonate mineral ikaite, which typically forms in the shallow subsurface of cold marine sediments. The region during the time of Nuwok Member depo...

Drilling for the International Continental Scientific Drilling Program (ICDP) Early Jurassic Earth System and Timescale project (JET) was undertaken between October 2020 and January 2021. The drill site is situated in a small-scale synformal basin of the latest Triassic to Early Jurassic age that formed above the major Permian-Triassic half-graben...

We held the MagellanPlus workshop SVALCLIME “Deep-time Arctic climate archives: high-resolution coring of Svalbard's sedimentary record”, from 18 to 21 October 2022 in Longyearbyen, to discuss scientific drilling of the unique high-resolution climate archives of Neoproterozoic to Paleogene age present in the sedimentary record of Svalbard. Svalbard...

There is a temporal correlation between the peak activity of the North Atlantic Igneous Province (NAIP) and the Paleocene–Eocene Thermal Maximum (PETM), suggesting that the NAIP may have initiated and/or prolonged this extreme warming event. However, corroborating a causal relationship is hampered by a scarcity of expanded sedimentary records that...

The International Ocean Discovery Program (IODP) Expedition 396 to the mid-Norwegian margin recovered >1300 m of pristinely preserved, volcanic ash-rich sediments deposited during the late Paleocene and early Eocene, from close to the centre of the North Atlantic Igneous Province (NAIP). Remarkably, many of these cores contain glendonites, pseudomo...

There is a temporal correlation between the peak activity of the North Atlantic Igneous Province (NAIP) and the Paleocene–Eocene Thermal Maximum (PETM), suggesting that the NAIP may have initiated and/or prolonged this extreme warming event. However, corroborating a causal relationship is hampered by a scarcity of expanded sedimentary records that...

The Miocene Climatic Optimum (~16.9-14.7 Ma) was the most recent interval in Earth's history with greenhouse conditions, which prevailed for nearly 2 million years. The optimum was associated with elevated atmospheric CO 2 (~400-600 ppm) and higher global temperatures, and therefore the optimum is considered one of the best analogues for future cli...

Marine sedimentary ikaite is the parent mineral to glendonite, stellate pseudomorphs found throughout the geological record which are most usually composed of calcite. Ikaite is known to be metastable at earth surface temperatures and pressures, readily breaking down to more stable carbonate polymorphs when exposed to warm (ambient) conditions. Yet...

An appraisal of ancient Earth’s climate dynamics is crucial for understanding the modern climate system and predicting how this might change in the future. Major climate-shift events in the Earth’s past demonstrate the scale, duration and response of the climate system to various global and local climate stressors. More than 650 million years of...

During the Middle and Late Jurassic, Europe and the Boreal regions formed a network of semi-restricted, relatively shallow marine basins. Consequently, stable oxygen (δ¹⁸O) and carbon (δ¹³C) isotope records from belemnites were strongly influenced by changes in palaeoceanography and climate. New data from eastern Greenland, which formed the western...

Pristinely preserved mineral pseudomorphs called glendonites, up to 1.6 m long, from the Palaeogene strata of Denmark allow detailed crystallographic characterisation and add to the understanding of the transformation of the precursor mineral, ikaite (CaCO3·6H2O), to calcite, which constitutes the glendonite. We describe Danish pseudomorphs after i...

Understanding the Earth’s climate system during past periods of high atmospheric CO2 is crucial for forecasting climate change under anthropogenically-elevated CO2. The Mesozoic Era is believed to have coincided with a long-term Greenhouse climate, and many of our temperature reconstructions come from stable isotopes of marine biotic calcite, in pa...

The Miocene climate was dynamic, oscillating between major glaciation events and greenhouse conditions (the so-called Miocene Climatic Optimum or MCO). However, forcing factors responsible for climatic transitions from one state to another are not fully understood, partly because palaeoclimatological records from northern mid to high latitudes are...

The Early Jurassic Toarcian Oceanic Anoxic Event (T-OAE) with its associated carbon-isotope excursion (CIE) was possibly one of the most pronounced periods of widespread oxygen deficiency in the Mesozoic ocean. The event has been extensively studied in order to understand the processes triggering the environmental perturbations and the extreme oxyg...

The early Eocene (c. 56-48 million years ago) experienced some of the highest global temperatures in Earth's history since the Mesozoic, with no polar ice. Reports of contradictory ice-rafted erratics and cold water glendonites in the higher latitudes have been largely dismissed due to ambiguity of the significance of these purported cold-climate i...

Clumped isotope based temperature estimates from exceptionally well-preserved belemnites from Staffin Bay (Isle of Skye, Scotland) reveal that seawater temperatures throughout the Middle-Late Jurassic were significantly warmer than previously reconstructed by conventional oxygen isotope thermometry. We demonstrate here that this underestimation by...

Late Jurassic – Early Cretaceous global carbon-cycle dynamics have mainly been inferred from Tethyan, Atlantic and Pacific carbon-isotope (δ13C) records. These records indicate a steady deceleration of the carbon cycle in Late Jurassic and Jurassic–Cretaceous (J–K) boundary times followed by a major mid-Valanginian carbon-cycle perturbation demarca...

Pristinely preserved mineral pseudomorphs called glendonites, up to 1.6 m long, from the Palaeogene strata of Denmark allow detailed crystallographic characterisation and add to the understanding of the transformation of the precursor mineral, ikaite (CaCO3·6H2O), to calcite, which constitutes the glendonite. We describe Danish pseudomorphs after i...

A new carbon isotope record for two high-latitude sedimentary successions that span the Jurassic–Cretaceous boundary interval in the Sverdrup Basin of Arctic Canada is presented. This study, combined with other published Arctic data, shows a large negative isotopic excursion of organic carbon (δ ¹³ C org ) of 4‰ (V-PDB) and to a minimum of −30.7‰ i...

Glendonites (calcite pseudomorphs after ikaite, a metastable, hydrated form of calcium carbonate), are contentious “cold climate indicators”, due to the natural occurrence of marine ikaite at near-freezing temperatures. However, laboratory studies suggest that the chemistry of the water from which the ikaite precipitates plays a strong role in ikai...

In order to understand the climate dynamics of the Mesozoic greenhouse world, it is vital to determine paleotemperatures from higher latitudes. For the Jurassic and Cretaceous climate , there are significant discrepancies between different proxies and between proxy data and climate models. We determined paleotemperatures from Late Jurassic and Earl...

The Early Cretaceous (145–100 Ma) was characterized by long-term greenhouse climates, with a reduced equatorial to polar temperature gradient, although an increasingly large body of evidence suggests that this period was punctuated by episodic global “cold snaps.” Understanding climate dynamics during this high-atmospheric CO2 period of Earth’s his...

We present new seawater temperature estimates for the Callovian to Kimmerigian interval (Middle to Upper Jurassic), from clumped isotope analyses of pristinely preserved belemnites from Staffin Bay, Isle of Skye, Scotland. We compare two belemnite genera, finding that generally Pachyteuthis give warmer temperatures than Cylindroteuthis. Our clumped...

Glendonites, pseudomorphs after marine sedimentary ikaite, are found throughout the Lower Cretaceous succession of Svalbard. Existing models for the ikaite-to-glendonite transformation do not explain the different petrological fabrics observed in the glendonites of Lower Cretaceous Svalbard. This study presents an improved model for the formation o...

In order to understand the climate dynamics of the greenhouse world of the Jurassic and Cretaceous, it is important to determine higher latitude palaeotemperatures. With respect to the Jurassic and Cretaceous there are significant differences between temperature proxies (e.g. oxygen isotope palaeothermometry vs. TEX86) and between proxy data and cl...

Significant changes in global climate and carbon cycling occurred during the Early Cretaceous. This study examines the expression of such climatic events in high-latitude Svalbard together with the stratigraphic utility of carbon-isotope stratigraphies. Isotopic analysis of fossil wood fragments (from the Rurikfjellet, Helvetiafjellet, and Caroline...

Abstract: During the Early Cretaceous, Spitsbergen was located at a palaeolatitude of ~60°N. Abundant fossil wood derived from conifer forests, dinosaur trackways, enigmatic deposits such as glendonites, and stable isotope data from the Early Cretaceous formations of Spitsbergen suggest that the climate at that time was much more dynamic than the t...