Elizabeth Griffith

The Ohio State University | OSU · School of Earth Sciences

Variations in speleothem calcium isotope ratios (δ⁴⁴Ca) are thought to be uniquely controlled by prior carbonate precipitation (PCP) above a drip site and, when calibrated with modern data, show promise as a semi‐quantitative proxy for paleorainfall. However, few monitoring studies have focused on δ⁴⁴Ca in modern cave systems. We present a multi‐ye...

Variations in speleothem calcium isotope ratios (δ44Ca) are thought to be uniquely controlled by prior carbonate precipitation (PCP) above a drip site and, when calibrated with modern data, show promise as a semi-quantitative proxy for paleorainfall. However, few monitoring studies have focused on δ44Ca in modern cave systems. We present a multi-ye...

Shallow-water platform carbonate δ13C may provide a record of changes in ocean chemistry through time, but early marine diagenesis and local processes can decouple these records from the global carbon cycle. Recent studies of calcium isotopes (δ44/40Ca) in shallow-water carbonates indicate that δ44/40Ca can be altered during early marine diagenesis...

The formation of authigenic carbonate in marine environments represents a process that buffers ocean chemistry and atmospheric carbon dioxide levels. The isotopic composition of calcium (δ 44/40 Ca) in authigenic carbonate can be used to investigate the calcium (Ca) cycle, seawater chemistry, and diagenesis of carbonate rocks, archiving key informa...

Correlating shallow shelf carbonates and their deep basin equivalents is a perennial challenge in the geosciences, with wide-ranging implications. This hurdle is well illustrated in the Llandovery succession of the Michigan Basin, USA, a 40- to 265-m-thick carbonate interval represented by three lithostratigraphic units: the Cataract, the Burnt Blu...

The marine biological carbon pump, which exports organic carbon out of the surface ocean, plays an essential role in sequestering carbon from the atmosphere, thus impacting climate and affecting marine ecosystems. Orbital variations in solar insolation modulate these processes, but their influence on the tropical Pacific during the Late Cretaceous...

The global climate of the Ordovician Period (486.9 to 443.1 Ma) is characterized by cooling that culminated in the Hirnantian glaciation. Chemical weathering of Ca- and Mg-bearing silicate minerals and the subsequent trapping of carbon in marine carbonates act as a sink for atmospheric CO2 on multi-million-year time scales, with basaltic rocks cons...

The marine biological carbon pump, which exports organic carbon out of the surface ocean, plays an essential role in sequestering carbon from the atmosphere, thus impacting climate and affecting marine ecosystems. Orbital variations in solar insolation modulate these processes, but their influence on the tropical Pacific during the Late Cretaceous...

It remains unclear whether waning of the volcanic degassing CO2 source or enhancement of the mafic (Ca, Mg-silicate) weathering CO2 sink, or both, caused global cooling leading to the Ordovician greenhouse–icehouse transition. We present a uniquely age-constrained and integrated Middle–Late Ordovician (470–450 Ma) continental weathering isotopic pr...

A new high-resolution, composite δ13Ccarb curve for the Michigan Basin, USA, was constructed using two stratigraphically overlapping subsurface cores that span the complete Llandovery interval. The Llandovery succession of the Michigan Basin measures between 140 m and 265 m thick and is represented by three lithostratigraphic groups: the Cataract (...

A global carbonate stratigraphic framework is needed to test models of paleoenvironmental change, but provinciality of age-diagnostic fossils and local controls on chemostratigraphic tools such as marine carbon isotope ratios (δ13C) have historically made long-distance correlation a difficult task. Radiogenic strontium isotope ratios (87Sr/86Sr) of...

Conodont apatite is ubiquitous in Paleozoic shallow- to deep-water carbonate sediments and has served as a crucial archive of seawater 87Sr/86Sr. However, some datasets have reported diagenetically altered 87Sr/86Sr values in apparently well-preserved conodont samples, highlighting a lack of understanding of the factors that affect 87Sr/86Sr signal...

Early to Middle Miocene sea-level oscillations of approximately 40–60 m estimated from far-field records1,2,3 are interpreted to reflect the loss of virtually all East Antarctic ice during peak warmth². This contrasts with ice-sheet model experiments suggesting most terrestrial ice in East Antarctica was retained even during the warmest intervals o...

A common approach to attract students in the United States to the geosciences is to emphasize outdoor experiences in the natural world. However, it is unclear how successful this strategy is. Specifically, the geosciences have been less successful than other sciences at recruiting a diverse workforce that reflects different perspectives and life ex...

Carbon cycle history Marine carbon includes organic and inorganic components, both of which must be accounted for to understand the global carbon cycle. Paytan et al. assembled a record of stable strontium isotopes ( ⁸⁸ Sr and ⁸⁶ Sr) derived from pelagic marine barite and used it to reconstruct changes in the deposition and burial of biogenic calci...

Future environmental change may profoundly affect oceanic ecosystems in a complex way, due to the synergy between rising temperatures, reduction in mixing and upwelling due to enhanced stratification, ocean acidification, and associated biogeochemical dynamics. Changes in primary productivity, in export of organic carbon from the surface ocean, and...

Reconstruction of ocean paleoproductivity and paleochemistry is paramount to understanding global biogeochemical cycles such as the carbon, oxygen and sulfur cycles and the responses of these cycles to changes in climate and tectonics. Paleo-reconstruction involves the application of various tracers that record seawater compositions, which in turn...

The Triassic carbonate-hosted Komsheche deposit of Central Iran, in the central segment of the Alpine-Himalayan orogen, is an ideal test site for tectonic-controlled ore formation processes. The mineralization consists of barite, fluorite, minor galena, and subordinate pyrite and chalcopyrite, and gangue minerals of dolomite, quartz, siderite, orga...

Precise measurements of calcium (Ca) isotopes have provided constraints on Ca cycling at global and local scales and quantified rates of carbonate diagenesis in marine sedimentary systems. Key to applying Ca isotopes as a geochemical tracer of Ca cycling, carbonate (bio)mineralization, and diagenesis is an understanding of the impact of multiple fa...

Chemical weathering of Ca- and Mg-bearing silicate minerals and the subsequent trapping of carbon in marine carbonates act as a sink for atmospheric CO2, driving shifts in global climate on geologic time scales. However, the role of silicate weathering in the fluctuating paleoclimate of the Devonian Period (419 to 359 Ma) is poorly understood. Alth...

Reconstructing the provenance of siliciclastic marine sediment is important for understanding sediment pathways and constraining palaeoclimate and erosion records. However, physical fractionation of different size fractions can occur during sediment transport, potentially biasing records derived from bulk sediment. In this study, records of radioge...

Marine barite (BaSO4) is a relatively ubiquitous, though minor, component of ocean sediments. Modern studies of the accumulation of barite in ocean sediments have demonstrated a robust correlation between barite accumulation rates and carbon export to the deep ocean. This correlation has been used to develop quantitative relationships between barit...

Calcium (Ca) isotopes have been utilized as geochemical tools since the 1970s, increasing in popularity and scope since the mid- to late 1990s. Research conducted over the past thirty years has revealed a range of applications for Ca isotopes that are highlighted in this introduction and Special Issue, as well as a series of interesting and fundame...

In Earth's surface environment, calcium (Ca) is an important mobile metal that is actively and passively transported in solution and within organic and mineral phases, being cycled and recycled during various biogeochemical processes. With the development of modern mass spectrometric techniques small variations in the stable and radiogenic isotopic...

The Ordovician Period (489 to 443 Ma) is marked by a transition from a warm, greenhouse climate to an icehouse by the Late Ordovician, making it a valuable case study for the question of how various, interconnected Earth systems drive and respond to global climate change. In service of this larger question, this study focuses on the role of one suc...

A stepwise change in atmospheric oxygen (O2) levels during the Ordovician has been attributed to the emergence of land plants. This phenomenon is tied to a major baseline shift in the stable carbon isotope (δ13C) curve and inferred increase in nutrient delivery and enhanced primary productivity in nearshore settings, which led to high organic carbo...

A giant mass-transport complex was recently discovered in the eastern Arabian Sea, exceeding in volume all but one other known complex on passive margins worldwide. The complex, named the Nataraja Slide, was drilled by International Ocean Discovery Program (IODP) Expedition 355 in two lo¬cations where it is ~300 m (Site U1456) and ~200 m thick (Sit...

International Ocean Discovery Program Expedition 355 drilled Sites U1456 and U1457 in Laxmi Basin (eastern Arabian Sea) to document the impact of the South Asian monsoon on weathering and erosion of the Himalaya. We revised the chronostratigraphic framework for these sites using a combination of biostratigraphy, magnetostratigraphy and strontium is...

Deep Sea Drilling Project (DSDP) Site 270, located in the central high of the Ross Sea, was cored to 422.5 m below seafloor (mbsf) and recovered a thick Oligocene to lower Miocene sequence of mudstone with varying amounts of ice rafted debris (IRD), overlain by ~20 m of Pliocene to Recent diatom silty clay with IRD. This site provides important tem...

A 1108.6 m long core was recovered at Site U1457 located on the Indus Fan in the Laxmi Basin of the eastern Arabian Sea during IODP Expedition 355. Shipboard examinations defined five lithologic units (I to V) of the lower Paleocene to Holocene sedimentary sequence. In this study, δ ¹³ C values of sedimentary organic matter (SOM) confirm the differ...

Barite (BaSO4) is a highly stable and widely-distributed mineral found in magmatic, metamorphic, and sedimentary rocks of all ages, as well as in soils, aerosol dust, and extraterrestrial material. Barite can form in a variety of settings in the oceans (hydrothermal deposits, cold seeps, water column, or within sediments) and on the continents (soi...

One of the most pronounced climate transitions in Earth's history occurred at the Eocene- Oligocene transition, ~34.0-33.6 m.y. ago. Marine sedimentary records indicate a dramatic decline in pCO2 coeval with global cooling during the transition. However, terrestrial records are relatively sparse, with conflicting interpretations of hydroclimate in...

A dramatic increase in unconventional drilling that utilizes hydraulic fracturing to extract oil/gas over the past decade has led to concern over handling and management of produced/ flowback water (PFW; hydraulic-fracturing wastewater) because the potential exists for its accidental release into the environment. This PFW contains high amounts of t...

Understanding past climate during contrasting boundary conditions can help in assessing imminent climate changes. Marine sediments offer a vast archive of past climate. Various indirect methods called proxies are used to infer principal climate parameters like temperature, salinity, productivity, monsoon intensity, ocean circulation, seawater pH, a...

In the Arabian Sea, South Asian monsoon (SAM)-induced high surface water productivity coupled with poor ventilation of intermediate water results in strong denitrification within the oxygen minimum zone (OMZ). Despite the significance of denitrification in the Arabian Sea, we have no long-term record of its evolution spanning the past several milli...

The middle Miocene climate transition (MMCT) is characterized by an abrupt 1‰ increase in benthic foraminiferal oxygen isotopes at ca. 13.8 Ma, marking expansion of the Antarctic Ice Sheet and transition of Earth's climate to a cooler, relatively stable glacial state. Also occurring during this period is a globally recognized positive carbon isotop...

We have documented the presence of celestine (SrSO4) within sediment accumulating at an artesian sulfidic spring (Zodletone Spring, Oklahoma) dominated by barite (BaSO4) precipitation associated with microbiological activity. The distribution and speciation of Sr in solid phases was determined by synchrotron-based micro-X-ray fluorescence spectrosc...

We have documented the presence of celestine (SrSO4) within sediment accumulating at an artesian sulfidic spring (Zodletone Spring, Oklahoma) dominated by barite (BaSO4) precipitation associated with microbiological activity. The distribution and speciation of Sr in solid phases was determined by synchrotron-based micro-X-ray fluorescence spectrosc...

For paleoceanographic studies, it is important to understand the processes that influence the calcium (Ca) isotopic composition of foraminiferal calcite tests preserved in the sediment record. Seven species of planktonic foraminifera from coretop sediments collectively exhibited a Ca temperature dependent fractionation of 0.013 per mil per °C. This...

This activity provides hands-on exploration of the impact of Rayleigh distillation on the isotopic composition of water in different experimental reservoirs. Similar experimental methods have been a primary source of information for understanding isotopic variations in the natural system. Students are exposed to fundamentals of isotope geochemistry...