Reinhard Kozdon

Columbia University | CU · Biology and PaleoEnvironment

The Paleocene‐Eocene thermal maximum (PETM, 56 Ma) is an ancient global warming event closely coupled to the release of massive amounts of ¹³C‐depleted carbon into the ocean‐atmosphere system, making it an informative analogue for future climate change. However, uncertainty still exists regarding tropical sea‐surface temperatures (SSTs) in open oce...

Cave calcite (i.e., speleothem) proxy records that span abrupt warming events, such as those of the last deglacial, may prologue regional responses of hydroclimate to 21st century warming. Proxy reliability is advanced by an understanding of the modern hydrologic system and controls on calcite growth. Here we integrate monitoring of Cave CWN in cen...

Geochemical records generated from the calcite tests of benthic foraminifera, especially those of the genera Cibicidoides and Uvigerina, provide the basis for proxy reconstructions of past climate. However, the extent to which benthic foraminifera are affected by postdepositional alteration is poorly constrained. Furthermore, how diagenesis may alt...

The 119 Ma Dinkey Dome pluton in the central Sierra Nevada Batholith is a peraluminous granite and contains magmatic garnet and zircon that are complexly zoned with respect to oxygen isotope ratios. Intracrystalline SIMS analysis tests the relative importance of magmatic differentiation processes vs. partial melting of metasedimentary rocks. Wherea...

Neogloboquadrina pachyderma is the dominant species of planktonic foraminifera found in polar waters and is therefore invaluable for paleoceanographic studies of the high latitudes. However, the geochemistry of this species is complicated due to the development of a thick calcite crust in its final growth stage and at greater depths within the wate...

A controversial aspect of Pliocene (5.3–2.6 Ma) climate is whether El Niño‐like (El Padre) conditions, characterized by a reduced trans‐equatorial sea‐surface temperature (SST) gradient, prevailed across the Pacific. Evidence for El Padre is chiefly based on reconstructions of sea‐surface conditions derived from the oxygen isotope (δ¹⁸O) and Mg/Ca...

Earth's hydrological cycle was profoundly perturbed by massive carbon emissions during an ancient (56 Ma) global warming event referred to as the Paleocene‐Eocene thermal maximum (PETM). One approach to gaining valuable insight into the response of the hydrological cycle is to construct sea‐surface salinity (SSS) records that can be used to gauge c...

The early Eocene (56 to 48 million years ago) is inferred to have been the most recent time that Earth's atmospheric CO2 concentrations exceeded 1000 ppm. Global mean temperatures were also substantially warmer than those of the present day. As such, the study of early Eocene climate provides insight into how a super-warm Earth system behaves and o...

The early Eocene (56 to 48 million years ago) is inferred to have been the most recent time that Earth's atmospheric CO2 concentrations exceeded 1000 ppm. Global mean temperatures were also substantially warmer than present day. As such, study of early Eocene climate provides insight into how a super-warm Earth system behaves and offers an opportun...

Deep-sea corals (DSCs), similar to their tropical counterparts, potentially provide continuous, high-resolution records of surrounding seawater conditions for up to a century or more. Several CWC elemental and isotopic ratios have been suggested as useful proxies of past oceanic conditions, for example for temperature, nutrients and CO2 system para...

Oxygen isotope ratios (δ¹⁸O) measured from planktic foraminifer shells are commonly used to reconstruct past surface ocean conditions, yet the shells of many planktic foraminifers are an aggregate mixture of multiple carbonate phases with differing δ¹⁸O compositions. Here we demonstrate how secondary ion mass spectrometry can be used to measure int...

Ammonites have disparate adult morphologies indicative of diverse ecological niches, but ammonite hatchlings are small (~1 mm diameter), which raises questions about the similarity of egg incubation and hatchling life mode in ammonites. Modern Nautilus is sometimes used as a model organism for understanding ammonites, but despite their outward simi...

Rationale Stable oxygen isotope ratios (δ¹⁸O values) measured in fish otoliths can provide valuable detailed information on fish life history, fish age determination, and ocean thermography. Traditionally, otoliths are sampled by micromilling followed by isotope ratio mass spectrometry (IRMS), but direct analysis by secondary ion mass spectrometry...

Earth surface temperatures warmed by ~5 °C during an ancient (~56 Ma) global warming event referred to as the Paleocene-Eocene thermal maximum (PETM). A hallmark of the PETM is a carbon isotope excursion (CIE) signaling the release of massive amounts of ¹³C-depleted carbon into the ocean-atmosphere system, but substrate-specific differences in the...

The oxygen isotope (δ¹⁸O) compositions of final chamber fragments of individual shells of the planktic foraminifer Orbulina universa were measured in situ via secondary ion mass spectrometry (SIMS) and by traditional gas-source mass spectrometry (GSMS) entailing acid digestion of sampled calcite. The paired SIMS-GSMS analyses were performed on fina...

Paleoclimate reconstructions based on speleothems require a robust interpretation of their proxies. Detailed transfer functions of external signals to the speleothem can be obtained using models supported by monitoring data. However, the transferred signal may not be stationary due to complexity of karst processes. Therefore, robust interpretations...

Understanding the sensitivity of the polar ice caps to a modest global warming (2–3 °C above preindustrial) is of paramount importance if we are to accurately predict future sea level change, knowledge that will inform both social and economic policy in the coming years. However, decades of study of the Pliocene (2.6–5.3 Ma), an epoch in recent Ear...

The significance of oxygen isotope ratios in Archean chert has long been debated. Cherts from the c. 3.4 Ga Strelley Pool Formation (SPF) (Pilbara Craton, Western Australia) host some of the oldest stromatolite and microfossil evidence for life, but the genesis and timing of silica cements has been unclear. Field relations, petrography and a combin...

Ammonites are the most iconic of extinct mollusks. Their wide spatial distribution and biostratigraphic utility make them ideally suited to investigate past climate. To date, stable isotope analyses of ammonites have focused on adult shells that can be sampled by bulk methods and have suggested adults had a nektobenthic mode of life. Eggs and hatch...

SEM/SIMS imaging and analysis of δ¹⁸O and δ¹³C in sandstones from a transect through the Illinois Basin (USA) show systematic μm-scale isotopic zonation of up to 10‰ in both carbonate and quartz cements of the middle-Ordovician St. Peter and Cambrian Mt. Simon formations. Quartz δ¹⁸O values are broadly consistent with the model of Hyodo et al. (201...

We measured δ¹⁸O values in modern and archaeological Pacific cod (Gadus macrocephalus) otoliths recovered from Aialik Bay on the Pacific coast of the Kenai Peninsula, Alaska, using a high precision ion microprobe. Values of δ¹⁸O were measured in as many as sixty 10-μm spots along 2–3 mm transects from the otolith core to its margin with high spot-t...

Thrombolites are buildups of carbonate that exhibit a clotted internal structure formed through the interactions of microbial mats and their environment. Despite recent advances, we are only beginning to understand the microbial and molecular processes associated with their formation. In this study, a spatial profile of the microbial and metabolic...

The modern North Pacific plays a critical role in marine biogeochemical cycles, as an oceanic sink of CO2 and by bearing some of the most productive and least oxygenated waters of the World Ocean. The capacity to sequester CO2 is limited by efficient nutrient supply to the mixed layer, particularly from deeper water masses in the Pacific's subarcti...

Past warm periods provide an opportunity to evaluate climate models under extreme forcing scenarios, in particular high (> 800 ppmv) atmospheric CO2 concentrations. Although a post hoc intercomparison of Eocene (∼ 50 Ma) climate model simulations and geological data has been carried out previously, models of past high-CO2 periods have never been ev...

This work addresses the potential utility of in situ carbon and oxygen isotope microanalysis (δ¹³C and δ¹⁸O) by secondary ion mass spectrometry (SIMS) in carbon sequestration research. A desirable long-term consequence of CO2-injection into underground rock formations at prospective sequestration sites (such as deep saline sandstone aquifers capped...

High-resolution analysis of growth increments, trace element chemistry and oxygen isotope ratios (δ18O) in otoliths were combined to assess larval and post-larval habitat use and growth of Awaous stamineus, an amphidromous goby native to Hawai‘i. Otolith increment widths indicate that all individuals experience a brief period of rapid growth during...

Past warm periods provide an opportunity to evaluate climate models under extreme forcing scenarios, in particular high (> 800 ppmv) atmospheric CO2 concentrations. Although a post-hoc intercomparison of Eocene (~50 million years ago, Ma) climate model simulations and geological data has been carried out previously, models of past high-CO2 periods...

Oxygen isotope (delta O-18) zonation in carbonate mineral cements is often employed as a proxy record (typically with millimeter-scale resolution) of changing temperature regimes during different stages of sediment diagenesis. Recent advances in secondary ion mass spectrometry allow for highly precise and accurate determinations of cement delta O-1...

Nautilus is often used as an analogue for the ecology and behavior of extinct externally shelled cephalopods. Nautilus shell grows quickly, has internal growth banding, and is widely believed to precipitate aragonite in oxygen isotope equilibrium with seawater. Pieces of shell from a wild-caught Nautilus macromphalus from New Caledonia and from a N...

SEM and CLFM images of transects on Nautilus belauensis, AMNH 102555. (PDF)

Table of all SIMS analyses including rejected values for sample Nautilus macromphalus, AMNH 105621. Complete data table of analyses in the outer prismatic layer of the wild-caught Nautilus macromphalus including bracketing standards and aragonite standard. (XLSX)

Table of all SIMS analyses including rejected values for sample Nautilus belauensis, AMNH 102555. Complete data table of analyses in the outer prismatic layer of the aquarium-reared Nautilus belauensis including bracketing standards and aragonite standard. (XLSX)

Significance We show for the first time, to our knowledge, that pedogenic (soil) carbonate mineral accumulations can preserve continuous paleoclimate records that rival the temporal resolution of widely used archives, such as speleothems or lake sediments. Using microanalysis of oxygen, carbon, and uranium isotopes coupled with uranium series datin...

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...

The interpretation of silicon isotope data for quartz is hampered by the lack of experimentally determined fractionation factors between quartz and fluid. Further, there is a large spread in published oxygen isotope fractionation factors at low temperatures, primarily due to extrapolation from experimental calibrations at high temperature. We prese...

An approach to coordinated, spatially resolved, in situ carbon isotope analysis of organic matter and carbonate minerals, and sulfur three- and four-isotope analysis of pyrite with an unprecedented combination of spatial resolution, precision, and accuracy is described. Organic matter and pyrite from eleven rock samples of Neoarchean drill core exp...

This study is Part II of a series that documents the development of a suite of calibration reference materials for in situ SIMS analysis of stable isotope ratios in Ca-Mg-Fe carbonates. Part I explored the effects of Fe2+ substitution on SIMS δ18O bias measured from the dolomite–ankerite solid solution series [CaMg(CO3)2–CaFe(CO3)2], whereas this c...

We document the development of a suite of carbonate mineral reference materials for calibrating SIMS determinations of δ18O in samples with compositions along the dolomite–ankerite solid solution series [CaMg(CO3)2–CaFe(CO3)2]. Under routine operating conditions for the analysis of carbonates for δ18O with an IMS 1280 instrument (at WiscSIMS, Unive...

Chinese speleothems (cave deposits) preserve a remarkable paleoclimate record in their oxygen isotope ratios (δ18O); the precise interpretation of this record has been the subject of stimulating discussion. Most studies link the δ18O variability in Chinese speleothems to regional summer monsoon rainfall and/or rainfall integrated between tropical s...

We thank Dvořak et al. for their comment (1) on our paper (2), in which we compare sulfur-cycling ∼1.8- and ∼2.3-Ga fossil communities with their modern counterparts and report that the community fabric of the fossil and modern microbes, as well as their organismal and cellular morphology, their interlinked energy-production via anaerobic sulfate-r...

Titanite is an important U-Pb chronometer for dating geologic events, but its high-temperature applicability depends upon its retention of radiogenic lead (Pb). Experimental data predict similar rates of diffusion for lead (Pb) and oxygen (O) in titanite at granulite-facies metamorphic conditions (T = 650-800 °C). This study therefore investigates...

Significance An ancient deep-sea mud-inhabiting 1,800-million-year-old sulfur-cycling microbial community from Western Australia is essentially identical both to a fossil community 500 million years older and to modern microbial biotas discovered off the coast of South America in 2007. The fossils are interpreted to document the impact of the mid-P...

Individual quartz overgrowths in siltstone of the late Cambrian Eau Claire Formation (Fm.) are systematically zoned in oxygen isotope ratio (δ18O). In situ analysis of δ18O was performed with 3 and 15 μm beam spots by secondary ion mass spectrometer (SIMS) on detrital quartz grains and quartz overgrowths. These results from thin lenses within imper...

In this study, we present experimental results from the planktic foraminifer Orbulina universa, cultured in the laboratory. We demonstrate that the δ13C of shell calcite precipitated in 13C-labeled seawater for 24 h can be resolved and accurately measured using Secondary Ion Mass Spectrometry (SIMS). Specimens maintained at 20 °C were transferred f...

High-resolution isotopic and geochemical analyses in a modern (1990–2008) Soreq Cave stalagmite are com-pared to instrumental records of rainfall and dripwater from the cave, with the aim of determining how seasonal-resolution climate information is transmitted to speleothem geochemistry. In situ, micron-scale analysis of oxygen isotope ratios (δ 1...

Stable carbon and oxygen isotope ratios in mammalian tooth enamel are commonly used to understand the diets and environments of modern and fossil animals. Isotope variation during the period of enamel formation can be recovered by intra-tooth microsampling along the direction of growth. However, conventional sampling of the enamel surface provides...

We developed a geochemical atlas of the Colorado River in Grand Canyon and in its tributary, the Little Colorado River, and used it to identify provenance and habitat use by Federally Endangered humpback chub, Gila cypha. Carbon stable isotope ratios (δ(13)C) discriminate best between the two rivers, but fine scale analysis in otoliths requires rar...

Oxygen isotopes are an attractive target for zoning studies because of the ubiquity of oxygen-bearing minerals and the dependence of mineral 18O/16O ratios on temperature and fluid composition. In this study, subtle intragrain oxygen isotope zoning in titanite is resolved at the 10-μm scale by secondary ion mass spectrometry. The patterns of δ18O z...

The formation of oceanic plagiogranite has been attributed primarily to either 1) extreme fractional crystallization of a mantle melt, or 2) partial melting of hydrated mafic crust, with support for the latter from field evidence and recent melting experiments. Remelting of hydrothermally-altered ocean crust could yield rocks (and minerals) with di...

[1] We report δ18O and minor element (Mg/Ca, Sr/Ca) data acquired by high-resolution, in situ secondary ion mass spectrometry (SIMS) from planktic foraminiferal shells and 100–500 µm sized diagenetic crystallites recovered from a deep-sea record (ODP Site 865) of the Paleocene-Eocene thermal maximum (PETM). The δ18O of crystallites (~1.2‰ Pee Dee B...

Evaluating the timing and origin of quartz cement is central to understanding how porosity is lost in sandstones during burial. Kinetic models of quartz cementation have been calibrated using large–scale datasets but have never been tested at the microscopic level at which cement forms. Here, we use high-precision, in situ oxygen isotope analyses o...

In this study, we show that the rate of shell precipitation in the extant planktic foraminifer Orbulina universa is sufficiently rapid that 12 h calcification periods in 18O-labeled seawater can be resolved and accurately measured using secondary ion mass spectrometry (SIMS) for in situ δ18O analyses. Calcifying O. universa held at constant tempera...

We report d18O and minor element (Mg/Ca, Sr/Ca) data acquired by high-resolution, in situ secondary ion mass spectrometry (SIMS) from planktic foraminiferal shells and 100-500 µm sized diagenetic crystallites recovered from a deep-sea record (ODP Site 865) of the Paleocene-Eocene thermal maximum (PETM). The d18O of crystallites (~1.2 per mil Pee De...

Cool tropical sea surface temperatures (SSTs) are reported for warm Paleogene greenhouse climates based on the d18O of planktonic foraminiferal tests. These results are difficult to reconcile with models of greenhouse gas-forced climate. It has been suggested that this "cool tropics paradox" arises from postdepositional alteration of foraminiferal...

The low δ18O values of Precambrian cherts have been widely used to infer that temperatures were higher and/or seawater δ18O was lower compared to today's oceans. However, the Precambrian cherts presented as evidence for these temperatures are neomorphosed from amorphous precursors that originally precipitated from ocean water, suggesting diagenetic...

The combination of ion microprobe analysis of d 18 O and confocal laser fluorescent microscope imaging of annual growth bands in a Soreq Cave speleothem provides sub-annual-scale climate information between 34 and 4 ka. This high-resolution methodology is ideal both for comparing seasonal climate patterns across broad windows of time and examining...

Rare ultrahigh-temperature–(near)ultrahigh-pressure (UHT–near-UHP) crustal xenoliths erupted at 11 Ma in the Pamir Mountains, southeastern Tajikistan, preserve a compositional and thermal record at mantle depths of crustal material subducted beneath the largest collisional orogen on Earth. A combination of oxygen-isotope thermometry, major-element...

Nacre, or mother-of-pearl, the tough, iridescent biomineral lining the inner side of some mollusk shells, has alternating biogenic aragonite (calcium carbonate, CaCO(3)) tablet layers and organic sheets. Nacre has been common in the shells of mollusks since the Ordovician (450 million years ago) and is abundant and well-preserved in the fossil reco...

In this study, we show that the rate of shell precipitation in the extant planktic foraminifer Orbulina universa is sufficiently rapid that 12 h calcification periods in 18 O-labeled seawater can be resolved and accurately measured using secondary ion mass spectrometry (SIMS) for in situ d 18 O analyses. Calcifying O. universa held at constant temp...

The slow growth rate of most speleothems prevents conventional (drill-sampling) methods from acquiring precise, seasonal-scale sampling. Micro-scale (e.g. ion microprobe and LA-ICP-MS) analysis in speleothems adds important detail to the climate record if seasonal climate variability is geochemically evident within the cave. Micro-analytical result...

The thermal, mechanical, and chemical evolution of a sedimentary basin exerts important controls on porosity and permeability of reservoir rocks. Oxygen isotope ratios of individual diagenetic cements record evidence of this history, but cannot be analyzed accurately by conventional techniques. Recent improvements for in situ analysis by ion microp...

Banded iron formations (BIFs) are chemical marine sediments dominantly composed of alternating iron-rich (oxide, carbonate, sulfide) and silicon-rich (chert, jasper) layers. Isotope ratios of iron, carbon, and sulfur in BIF iron-bearing minerals are biosignatures that reflect microbial cycling for these elements in BIFs. While much attention has fo...

Previous efforts to constrain the timing of Paleoproterozoic atmospheric oxygenation have documented the disappearance of large, mass-independent sulfur isotope fractionation and an increase in mass-dependent sulfur isotope fractionation associated with multiple glaciations. At least one of these glacial events is preserved in diamictites of the ∼2...

We characterize oxygen isotope zoning within single titanite crystals from the Carthage-Colton mylonite zone (CCMZ), Adirondack Mountains (New York State, United States), by ion microprobe. Smooth gradients of δ18O, up to 0.6‰ over 90 μm, resulted from diffusive exchange of oxygen during cooling from peak metamorphic temperatures of 650–700 °C. Mod...

Cool tropical sea surface temperatures (SSTs) are reported for warm Paleogene greenhouse climates based on the δ18O of planktonic foraminiferal tests. These results are difficult to reconcile with models of greenhouse gas–forced climate. It has been suggested that this “cool tropics paradox” arises from postdepositional alteration of foraminiferal...

The Cassia plutonic complex (CPC) is a group of variably deformed, Oligocene granitic plutons exposed in the lower plate of the Albion–Raft River–Grouse Creek (ARG) metamorphic core complex of Idaho and Utah. The plutons range from granodiorite to garnet-bearing, leucogranite, and during intrusion, sillimanite-grade peak metamorphism and ductile at...