Ashley N. Martin- PhD, University of Wollongong. Chemistry MChem, University of York.
- Assistant Professor at Northumbria University
Ashley N. Martin
- PhD, University of Wollongong. Chemistry MChem, University of York.
- Assistant Professor at Northumbria University
PI on Project MoVE: Mechanisms of Vanadium Enrichments in shale-hosted deposits: insights from a novel redox tracer
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27
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Introduction
PI on Project MoVE: Mechanisms of Vanadium Enrichments in shale-hosted deposits: insights from a novel redox tracer
Skills and Expertise
Current institution
Additional affiliations
October 2011 - July 2017
July 2022 - October 2023
August 2010 - July 2011
Publications
Publications (27)
Unusually high δ¹⁵N values in the Neoarchean sedimentary record in the time period from 2.8 to 2.6 Ga, termed the Nitrogen Isotope Event (NIE), might be explained by aerobic N cycling prior to the Great Oxidation Event (GOE). Here we report strongly positive δ¹⁵N values up to +42.5 ‰ in ~2.75 – 2.73 Ga shallow-marine carbonates from Zimbabwe. As th...
The biological N cycle on early Earth is enigmatic because of limited data from Archean (meta)sediments and the potential alteration of primary biotic signatures. Here we further investigate unusual 15N enrichments reported in 2.7 Ga meta-sediments from the Abitibi greenstone belt, Canada, which possibly suggest a 15N-enriched Archean atmosphere. A...
The invention of photosynthesis was a key interval in Earth’s history, initiating major changes in the evolution of the oceans and atmosphere. Many studies suggest that oxygen levels were already enhanced before the Paleoproterozoic Great Oxidation Event (GOE, 2.45–2.32 Ga). However, the timing of the onset of photosynthetic oxygenation, as well as...
Speleothems are calcium carbonate deposits formed by the degassing of high pCO2 groundwaters typically found in karstic caves. They are a globally distributed geological archive that store information of climate and environmental changes at the time of their formation in multiple proxies, and crucially, provide excellent age control through uranium...
The stable isotope composition of redox-sensitive trace metals, such as vanadium (V), in marine sediments provides the potential to reconstruct paleo-redox conditions in ancient sedimentary environments. However, in addition to the redox state of the basin at the time of sediment deposition, metal isotope signatures may also be affected by other fa...
During the last African Humid Period (AHP; 15–5 ka), many lakes in the East African Rift System (EARS) experienced pronounced lake-level variations that dramatically transformed the hydrological landscape. Currently dry, saline or marshy-wetland terminal lakes became vast waterbodies, interconnected via overflow sills resulting in the formation of...
Dissolved silicon (dSi) is a key nutrient in the oceans, but data regarding Si isotopes in coastal aquifers are not widely available. Here we investigate the Si isotopic composition of 12 fresh and 16 saline groundwater samples from Rottnest Island, Western Australia, which forms part of the world's most extensive aeolianite deposit (the Tamala Lim...
Stromatolites represent some of the earliest evidence for life and are valuable geochemical archives for understanding the rise of oxygen on early Earth. Metal redox proxies in carbonates, such as stable uranium isotopes (238U/235U), are useful for assessing the oxidation state of ancient waterbodies, but may also be sensitive to local water chemis...
Dissolved silicon (DSi) is a key nutrient in the oceans, but there are few data available regarding Si isotopes in coastal aquifers. Here we investigate the Si isotopic composition of 12 fresh and 17 saline groundwater samples from Rottnest Island, Western Australia, which forms part of the world’s most extensive aeolianite deposit (the Tamala Lime...
Water-rock interactions in aquifer systems are a key control on water quality but remain poorly understood. Lithium (Li) isotopes are useful for understanding water-rock interactions, but there are few data available for groundwater aquifers. Here we present a Li isotope dataset for rainfall and groundwater samples from a carbonate island aquifer s...
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https://drive.google.com/file/d/1p9MaenELHDAL0iA1j2aB2MrB2oZVwozb/view?usp=share_link _____________________________________________________________________________________Uranium (U) isotopes are useful for constraining the timescales of weathering and erosion processes. The (234 U/ 238 U) activity ratio (parentheses denote activity...
There is a lack of knowledge regarding in-vehicle concentrations of nitrogen dioxide (NO2) during transit through road tunnels in urban environments. Furthermore, previous studies have tended to involve a single vehicle and the range of in-vehicle NO2 concentrations that vehicle occupants may be exposed to is not well defined. This study describes...
The uranium-series isotopes can be used to quantify the timescales on which Earth-surface processes operate; this is essential before we can begin to try to understand how the erosion of the Earth's surface responds to climate change. The traditional uranium-series methodology analyses the isotopic composition of the bulk sediment; however, this re...
Group 4 metal complexes Zr-1 to Zr-4, Ti-4 and Ti-4a that contain an (OSSO)-type tetradentate bis(phenolate) ligand were found to initiate the ring-opening polymerization of meso-, rac-, and L-lactides in toluene solution. The polymerizations were controlled with initiator efficiency values around one and gave polymers with low polydispersity (Mw/M...
