David L. Dettman

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Verified

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• PhD
• Research Scientist at University of Arizona

This study investigates the mineralogical and geochemical characteristics of the middle-upper Jurassic Sargelu, Naokelekan, and Barsarin formations in the Sargelu area, northeastern Iraq. The study aims to interpret the provenance, tectonic setting, paleoclimate, and paleoweathering processes that shaped these formations using X- ray diffraction, X...

The Paleocene-Eocene (P-E) Sinjar Formation from Kalka Smaq section, Dokan area, Sulaimaniya, northeastern Iraq has been studied in terms of mineralogy and geochemistry using X-Ray Diffraction (XRD) supported by Scanning Electron Microscopy (SEM) and elemental X-Ray Fluorescence (XRF) geochemical analyses in addition to stable isotopic C and O anal...

The geochemistry of tropical coral skeletons is widely used in paleoclimate reconstructions. However, sub‐aerially exposed corals may be affected by diagenesis, altering the aragonite skeleton through partial dissolution, or infilling of secondary minerals like calcite. We analyzed the impact of intra‐skeletal calcite on the geochemistry (δ¹⁸O, Sr/...

Biostratigraphy of the Sinjar Formation is investigated in two sections (Dokan and Sinjar) from northeastern and northwestern Iraq, respectively. Two hundred samples from all the limestones and marl that form the main lithological components of the studied sections were collected. The studied limestones and marl are rich in microfossils. Through th...

The Paleocene-Eocene (P-E) Sinjar Formation from Kalka Smaq section, Dokan area, Sulaimaniya, northeastern Iraq has been studied in terms of mineralogy and geochemistry using X-Ray Diffraction (XRD) supported by Scanning Electron Microscopy (SEM) and elemental X-Ray Fluorescence (XRF) geochemical analyses in addition to stable isotopic C and O anal...

Changing environmental temperatures impact the physiological performance of fishes, and consequently their distributions. A mechanistic understanding of the linkages between experienced temperature and the physiological response expressed within complex natural environments is often lacking, hampering efforts to project impacts especially when futu...

Since its initial discovery as a natural isotopologue of dihydrogen oxide (1H2O), extensive research has focused on the biophysical, biochemical, and pharmacological effects of deuterated water [2H2O (D2O, also referred to as ‘heavy water’)]. Here, using diverse panels of cultured human malignant melanoma and pancreatic ductal adenocarcinoma (PDAC)...

Since its initial discovery as a natural isotopologue of dihydrogen oxide (1 H2 O), extensive research has focused on the biophysical, biochemical, and pharmacological effects of deuterated water (2 H2 O [D2 O, also referred to as "heavy water"]). Using a panel of cultured human pancreatic ductal adenocarcinoma (PDAC) cells we have profiled (i) D2...

Carbonate clumped isotope abundance is an important paleothermometer, but measurement is difficult, slow, and subject to cardinal mass (m/z) interferences using isotope ratio mass spectrometry (IRMS). Here, we describe an optical spectroscopic measurement of carbonate clumped isotopes. We have adapted a tunable infrared laser differential absorptio...

In island systems, nitrogen-rich seabird guano is a marine subsidy that can shape terrestrial plant communities. In zones of nutrient upwelling such as the Gulf of California, copious seabird guano is commonplace on bird islands. Several bird islands host regionally unique cactus forests, especially of the large columnar cactus, cardón (Pachycereus...

The cause of Cenozoic uplift of the Colorado Plateau is one of the largest remaining problems of Cordilleran tectonics. Difficulty in discriminating between two major classes of uplift mechanisms, one related to lithosphere modification by low-angle subduction and the other related to active mantle processes following termination of subduction, is...

Marine nutrient subsidies can shape terrestrial plant biodiversity. In island systems, nitrogen-rich seabird guano is a large component of such marine subsidies. In zones of nutrient upwelling such as the Gulf of California, copious seabird guano is commonplace on bird islands. Several bird islands host regionally unique cactus forests, especially...

Yellowfin tuna (Thunnus albacares) is a highly exploited species in the Indian Ocean. Yet, their stock structure is still not well understood, hindering to assess the stock at a suitable spatial scale for management. Here, young-of-the-year (<4 months) yellowfin tuna otoliths were collected in 2018 and 2019, from four major nursery areas in the Ind...

Yellowfin tuna of the Indian Ocean is overfished, and a better understanding of the stock structure is needed to enable sustainable management. Here, otolith δ18O values of young-of-the-year fish from known nursery areas of the equatorial Indian Ocean (West, Central and East) were used to establish a reference isotopic signature to predict the orig...

Stable isotope analysis is pivotal for investigating the paleodiet and paleoecology of past mammals. In this paper, we analyzed thirty fossil enamel samples belonging to the families Suidae, Rhinocerotidae, and Deinotheriidae for δ13Cenamel and δ18Oenamel composition to investigate paleodiet and paleoecology of middle Miocene mammals of the Siwalik...

The chemical composition of otoliths (earbones) can provide valuable information about stock structure and connectivity patterns among marine fish. For that, chemical signatures must be sufficiently distinct to allow accurate classification of an unknown fish to their area of origin. Here we have examined the suitability of otolith microchemistry a...

We present a timeline of the carbon, nitrogen, and oxygen stable isotope compositions of 10 unionid mussel shells across three species–Threeridge (Amblema plicata), Ebonyshell (Reginaia ebenus), and Pimpleback (Cyclonaias pustulosa)—collected live in 2011 from the Tennessee River near Paducah, Kentucky, USA. Inorganic aragonite δ¹⁸O profiles were c...

The paleotopographic history of the North American Cordilleran orogen holds the key to understanding mechanisms of orogenesis and subsequent orogenic collapse. It has been suggested that the orogenic front in western Montana (USA) and Alberta (Canada) was more than 4 km high during Late Cretaceous−early Eocene contractional deformation and during t...

Stable isotope ratios of otoliths (δ¹³C and δ¹⁸O) can be used as a habitat index in anadromous fish, because there are marked differences between freshwater and marine settings. Here we report the results of 84 otoliths of chum salmon (Oncorhynchus keta) collected from three locations (Site-A, Site-B, and Site-C) in China, where all the estuaries f...

The tall (>4 m), charismatic and threatened columnar cacti, pasacana [Echinopsis atacamensis (Vaupel) Friedrich & G.D. Rowley)], grows on the Bolivian Altiplano and provides environmental and economic value to these extremely cold, arid and high-elevation (~4000 m) ecosystems. Yet very little is known about their growth rates, ages, demography and...

Wet summers and dry winters are an essential feature of monsoon climates, but quantification of change in wet-dry seasonality through time is very challenging because most geological materials fail to record sub-annual environmental signals, instead integrating years, decades, or centuries. Here we quantify Asian wet-dry seasonality since the middl...

Stable isotope analysis has become a leading tool to investigate palaeodiet and palaeoecology of past mammalian communities over the last three decades. In this paper we have utilized thirty fossil dental samples belonging to three families (viz. Deinotheridae, Rhinocerotidae and Suidae) for δ13C and δ18O analyses to investigate palaeodiet and pala...

Interactions between midlatitude westerlies and the Pamir–Tian Shan mountains significantly impact hydroclimate patterns in Central Asia today, and they played an important role in driving Asian aridification during the Cenozoic. We show that distinct west-east hydroclimate differences were established over Central Asia during the late Oligocene (c...

The geologic record of the Pleistocene Epoch in the northern Salton Trough—the portion of the northwest landward extension of the Gulf of California Shear Zone that is north of the U.S.-Mexico border—has long been interpreted as entirely non-marine and largely lacustrine. It has been thought that by Pleistocene time the Colorado River had deposited...

Stable isotope ratio measurements of dissolved inorganic carbon (δ¹³CDIC) provide a useful indication of carbon sources, sinks and fluxes in river ecosystems. Because of the incorporation of dissolved inorganic carbonate during shell growth, shells of aquatic mollusks have the potential to record DIC information and to be a proxy for δ¹³CDIC in thi...

The high precision measurement of doubly-substituted (“clumped”) isotopologues in CO2 is a topic of interest in isotope geochemistry. Here we describe the performance of a new isotope ratio laser spectrometer using tunable infrared laser differential absorption spectroscopy (TILDAS). The TILDAS instrument has two continuous-wave lasers to simultane...

The carbon isotopic ratios of organic matter in fish fossils from diatomites and other lake beds in the HSPDP drill core from Tugen Hills, Kenya (2.56–3.29 Ma) reflect trophic resource uses and can indicate the dietary habitats of fish in the paleolake. This information offers insight into how fish communities responded to lake-level fluctuations d...

Varied approaches (palaeobiodiversity, palaeobiogeography, bioerosion, geochemistry) to unique Patagonian late Quaternary molluscan assemblages in the southwestern Atlantic, with ages especially from interglacial Marine Isotope Stage (MIS) 5e and MIS 1, provide large-scale and long-temporal palaeoenvironmental data for the southern SWA. Together wi...

The plant family Cactaceae is considered among the most threatened groups of organisms on the planet. The threatened status of the cacti family has created a renewed interest in the highly evolved physiological and morphological traits that underpin their persistence in some of the harshest sub-tropical environments in the Americas. Among the most...

PAHs in sediment cores have been investigated as a useful proxy of historic fire events in the watershed of an estuary. Oxygen poor and anoxic lake bottom conditions in estuarine brackish lakes Shinji and Nakaumi could prevent the oxidization of polycyclic aromatic hydrocarbons (PAHs) and preserve a record of PAHs in sediments. PAHs emitted from wo...

We are among the scientists who have documented the environmental and ecological changes to the Upper Gulf of California following the reduction in the Colorado River’s flow. We object to any suggestion that our research supports Manjarrez-Bringas et al.’s conclusion that the decline in the Colorado River’s flow is the reason for the decline in the...

Giant saguaro (Carnegiea gigantea) is one of the longest‐lived and massive cacti species in the Americas. They occur throughout the Sonoran Desert region with a distribution spanning a five‐fold gradient in mean annual precipitation. Relationships between fitness traits, including stem growth, and spatio‐temporal climate patterns are still poorly u...

Premise of the Study Giant cacti species possess long cylindrical stems that store massive amounts of water and other resources to draw on for photosynthesis, growth, and reproduction during hot and dry conditions. Across all giant cacti taxa, stem photosynthetic surface area to volume ratio (S:V) varies by several fold. This broad morphological di...

Carbonate shells can be used in the detection of climate change and ocean acidification in fisheries science and aquaculture. In this study, we reported stable carbon and oxygen isotope ratios (δ¹³C and δ¹⁸O) in sea scallop (Patinopecten caurinus) shells from the Island Scallop Limited (ISL) in Vancouver Island, British Columbia, Canada, where appr...

Intra-annual growth rates from the bivalve mollusk Lampsilis cardium (Unionidae) were reconstructed using measured oxygen isotope (δ¹⁸O) profiles together with high-resolution environmental records. Mussels from a single cohort (2007) were grown in two different settings at the Columbus Zoo & Aquarium Freshwater Mussel Conservation & Research Cente...

Uncertainty over the depositional environment of the late Miocene and early Pliocene Bouse Formation hinders our understanding the evolution of the lower Colorado River corridor. Competing marine and lacustrine models for the origin of the southern Bouse Formation remain extremely difficult to reconcile after nearly 60 yr of study. This paper compa...

Suborbital-scale climate variations, possibly caused by solar activity, are observed in the Holocene and last-glacial climates. Recently published bicentennial-resolution paleoceanic environmental records reveal millennial-scale high-amplitude oscillations postdating the last geomagnetic reversal in the Marine Isotope Stage (MIS) 19 interglacial. T...

Stable isotope ratios (¹⁸O/¹⁶O, ¹³C/¹²C and ¹⁷O/¹⁶O) in carbonates have contributed greatly to understanding of Earth and planetary systems, climates, and history. Current methods for measuring isotopologues of CO2 derived from CaCO3 are primarily gas-source isotope ratio mass spectroscopy (IRMS). However, IRMS has drawbacks, such as mass overlap b...

The weakening of the geomagnetic field causes an increase in galactic cosmic ray (GCR) flux. Some researchers argue that enhanced GCR flux might lead to a climatic cooling by increasing low cloud formation, which enhances albedo (umbrella effect). Recent studies have reported geological evidence for a link between weakened geomagnetic field and cli...

Rationale: Induction module cavity ring-down spectroscopy (IM-CRDS) has been proposed as a rapid and cost-effective alternative to cryogenic vacuum distillation (CVD) and isotope ratio mass spectrometry (IRMS) for the mesurement of δ(18) O and δ(2) H values in matrix-bound waters. In the current study, we characterized the performance of IM-CRDS r...

The paleoelevation and size of the North America Cordilleran orogen during the late Cretaceous–Paleogene contractional and subsequent extensional tectonics remain enigmatic. We present new estimates of paleorelief of the northern Cordilleran orogenic front during the middle and late Eocene using oxygen isotope compositions of unaltered molluscan fo...

Volume-to-surface area ratio (V:S) across stem succulent taxa varies by almost two orders of magnitude. The broad range in V:S of cacti and other succulent species likely has considerable importance for adaptation since stem volume determines the storage capacity of water, carbon and nutrients and stem surface area is directly related to whole-stem...

Otoliths of Atlantic bluefin tuna (Thunnus thynnus) collected from the Mediterranean Sea and North Atlantic Ocean were analyzed to evaluate changes in the seawater isotopic composition over time. We report an annual otolith delta C-13 record that documents the magnitude of the delta C-13 depletion in the Mediterranean Sea between 1989 and 2010. Atl...

The southern Bouse Formation (late Miocene-early Pliocene) in Blythe basin, CA-AZ, contains a controversial record of the events that preceded the integration of the developing Colorado River with the Gulf of California. High resolution microfaunal and stable isotope (δ18O, δ13C; VPDB) data from a key outcrop of marl and claystone record an abrupt...

Many studies of Quaternary climate make use of terrestrial stable isotope records which are interpreted based on seasonal patterns of stable isotopes in modern precipitation. Multi-decade records of isotopes in rainfall allow testing of the assumed behavior of isotope signals used for this interpretation on multi-year to decadal scales. A 32-year r...

Previous studies of live-collected pre-weapons testing mollusk shells in the northern Gulf of California have demonstrated that the local radiocarbon reservoir effect (ΔR) is large and highly variable. To test the validity of this observation for paired charcoal and shell samples from archaeological contexts, we dated samples from four shell midden...

Otoliths are important proxies for climate change and ecological studies and are typically stored in glycerin or ethanol for preservation. This study is the first attempt to assess the isotopic effects of these preservatives on carbon and oxygen isotope ratios of otolith aragonite. Experimental tests from the 4th annulus of dried Pacific halibut ot...

We present a detailed stratigraphy of the lithology, sedimentary facies, magnetic susceptibility, and chemical composition of a 54-m thick core sequence drilled adjacent to the Chiba section, a candidate for the Global Boundary Stratotype Section and Point of the early–middle Pleistocene boundary. Siltstones rich in trace fossils are dominant throu...

This paper reports a new result for the isotopic differences between the left and right sagittal otoliths of Pacific halibut Hippoglossus stenolepis, a flatfish with both eyes on the right side. Using microsampling techniques we were able to collect subsamples from the nucleus and the 5th and 8th annulus from 63 pairs of halibut otoliths. Isotopic...

This article integrates geological, biological, ethnographic, and archaeological lines of evidence to reconstruct fishing patterns between approximately 4100 and 500 BC in the northern Gulf of California. In addition to shell collecting along the coast, several species of fish were captured, mainly endemic sciaenids of the upper gulf. Our study foc...

Hydrogen in organic tissue resides in a complex mixture of molecular contexts. Some hydrogen, called non-exchangeable (Hnon), is strongly bound, and its isotopic ratio is fixed when the tissue is synthesized. Other pools of hydrogen, called exchangeable hydrogen (Hex), constantly exchange with ambient water vapor. The measurement of the δ(2)Hnon in...

Assessment and management of Atlantic bluefin tuna Thunnus thynnus populations is hindered by our lack of knowledge regarding trans-Atlantic movement and connectivity of east- ern and western populations. Here, we evaluated migratory and homing behaviors of bluefin tuna in several regions of the North Atlantic Ocean and Mediterranean Sea using chem...

Columnar cacti occur naturally in many habitats and environments in the Americas but are conspicuously dominant in very dry desert regions. These majestic plants are widely regarded for their cultural, economic, and ecological value and, in many ecosystems, support highly diverse communities of pollinators, seed dispersers, and frugivores. Massive...

Archaeological marine shell artifacts moving over long distances may reveal the remnants of social networks, social currency, and the nuances of exchange. For the southwestern United States and northern Mexico, potential sources of marine shell are predominantly the Gulf of California and Pacific Ocean. There exists some taxonomic overlap between m...

The potential for using Raman spectroscopy to measure stable oxygen isotope ratios (18O/16O) in carbonates is evaluated by measuring the Raman spectra and isotope ratios of a suite of 60 synthesized, 18O-enriched calcite crystals ranging in composition from natural abundance (0.2 mole-% 18O) to 1.2 mole-% 18O. We determined the Raman-inferred isoto...

The climatic effects of cloud formation induced by galactic cosmic rays (CRs) has recently become a topic of much discussion. The CR-cloud connection suggests that variations in geomagnetic field intensity could change climate through modulation of CR flux. This hypothesis, however, is not well-tested using robust geological evidence. Here we prese...

Abstract Calcite in speleothems commonly yields a record of varying delta18O over the past hundreds to thousands of years. Such variation is usually interpreted in terms of the isotope amount effect in precipitation, namely that high values of delta18O correspond to low ...

The relationship between ostracod valve minor element chemistry and environmental factors has been the subject of many studies, which are reviewed here with a focus on Mg/Ca in marine ostracods and both Mg/Ca and Sr/Ca in freshwater and hypersaline ostracods. In the marine taxa Krithe and Loxoconcha, Mg/Ca ratios in the shell respond to temperature...

The Byzantine Empire managed a complex administrative network that controlled the mining and processing of natural resources from within its boundaries. Ancient sources note that many mining camps contained criminal laborers and elite administrators transported from distant locales. This analysis explores the presence of non-local individuals in a...

Five recent radiocarbon assays on wood charcoal within archaeological sites from the Puerto Peñasco area, Sonora, Mexico indicate use of the marine resources of the northern Gulf of California area during the Middle Archaic through the Late Archaic periods, ca. 3800 B.C.-A.D. 100. The archaeological shell middens of the region are generally thought...

Background/Question/Methods The ratio of 15N/14N (δ15N) from consumer and prey tissue is commonly used in ecological studies to determine trophic level, food web structure, and mean trophic level in aquatic ecosystems. Tracking food chain length or mean trophic level in a system over time provides insights about biodiversity and ecosystem resilien...

Because of competing demands for freshwater, restoration of estuaries requires estimates of inflows to sustain key species. In this study we estimated the pre-dam salinities of the Colorado River estuary by using oxygen isotopes in subfossil shells of the bivalve mollusk Mulinia coloradoensis. Since the construction of upstream dams and water diver...

The relationship among H2S, total organic carbon (TOC), total sulfur (TS) and total nitrogen contents of surface sediments (0–1 cm) was examined to quantify the relationship between H2S concentrations and TOC content at the sediment water interface in a coastal brackish lake, Nakaumi, southwest Japan. In this lake, bottom water becomes anoxic durin...

Carbonate clumped isotope (Δ_(47)) thermometry provides an independent test of the metrics used to assess the preservation of carbonate rocks and fossils. Additionally, Δ_(47) thermometry, when combined with other geochemical and structural measurements, may establish whether diagenesis occurred under closed-system conditions, open-system condition...

Evidence shows that solar activity influences climate on a global scale. In the mid-latitude region, climate change is expected to change precipitation patterns. Concurrently, variation in solar activity may influence phytoplankton productivity. It seems that these changes should be recorded in sediment and organic matter deposits in coastal lagoon...

The development of quantitative lacustrine paleotemperature records is critical to understanding how past climate changes influenced the ecology and hydrology of lakes. Whereas paleoecological transfer functions, TEX-86 and clumped isotopes are all widely applied methods, all have their limitations. We aim to further the development of an alternati...

The Antarctic continent was uplifted by glacioisostatic rebound due to the regression of ice sheets after the last glacial period. Today's saline lakes were formed in shallow basins originally below sea level. Antarctic hypersaline lakes are formed by concentration of isolated seawater bodies as affected by recent climate change. Many saline lakes...

In the Common Era coastal lagoon environments change through anthropogenic modification of landforms and the landscape evolution that occurs with eustatic sea level change. The recent lake water environment in Nakaumi Lagoon, Southwest Japan, has undergone large changes due to both of these factors. In this study, the paleoenvironment of the Common...

In the 1950-1960’s the construction of dams and diversions significantly reduced the Colorado River’s flow into the Gulf of California. Nearly simultaneously, the fishing industry in the Gulf of California began to boom. Although quantifying the ecosystem responses to these different pressures is important to ecosystem management, it is very diffic...

Reconstruction of the timing and pattern of exhumation of basement-involved uplifts during the Laramide is essential to the understanding of the mechanisms of crustal shortening and thickening in the region. We use reconstructions of the 87sr/86sr ratios of Late Cretaceous-early Cenozoic river water from fossil shells in six basins of the Rocky Mou...

Crassulacean acid metabolism (CAM) and the capacity to store large quantities of water are thought to confer high water use efficiency (WUE) and survival of succulent plants in warm desert environments. Yet the highly variable precipitation, temperature and humidity conditions in these environments likely have unique impacts on underlying processes...

Numerous biological and chemical paleorecords have been used to infer paleoclimate, lake level fluctuation and faunal composition from the drill cores obtained from Lake Malawi, Africa. However, fish fossils have never been used to examine changes in African Great Lake vertebrate aquatic communities nor as indicators of changing paleolimnological c...

Shallow subduction of the Farallon plate beneath the western United States has been commonly accepted as the tectonic cause for the Laramide deformation during Late Cretaceous through Eocene time. However, it remains unclear how shallow subduction would produce the individual Laramide structures. Critical information about the timing of individual...