I.L. Hendy

I.L. Hendy
University of Michigan | U-M · Department of Earth and Environmental Sciences

PhD University of California Santa Barbara

About

152
Publications
13,727
Reads
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3,195
Citations
Additional affiliations
August 2002 - present
University of Michigan
Position
  • Professor (Associate)
June 2000 - August 2002
University of British Columbia - Vancouver
Position
  • Postdoctoral Fellowship
January 1994 - July 1995
The University of Waikato
Position
  • Research Assistant

Publications

Publications (152)
Article
The Mediterranean climate of southern California is marked by droughts and extreme precipitation events. Here we use elemental variations generated by scanning X-ray fluorescence (XRF) to identify droughts and floods in recently deposited (1755–2008) sediments of Santa Barbara Basin (SBB) from box core SPR0901-04BC. The first principal component (P...
Article
Full-text available
High-resolution studies of pollen in laminated sediments deposited in Santa Barbara Basin (SBB) core SPR0901-02KC reflect decadal-scale fluctuations in precipitation spanning the interval from AD 800 to 1600. From AD 800 to 1090 during the Medieval Climate Anomaly (MCA) SBB sediments were dominated by xeric vegetation types (drought-resistant coast...
Article
A 30,000-year-long pollen record from the Gulf of Tehuantepec, southern Mexico shows the varying influence of air temperature, precipitation and eustatic sea-level rise on changes in coastal and upland vegetation patterns. During the late-glacial period, pine-juniper forests grew in the Sierra Madre del Sur along the Pacific Slope with broadleaf fo...
Article
The sedimentary record of the Coniacian–Santonian Oceanic Anoxic Event 3 (OAE 3) in the North American Western Interior Seaway is characterized by a prolonged period of enhanced organic carbon (OC) burial. This study investigates the role of Fe in enhancing organic matter preservation and maintaining elevated primary productivity to sustain black s...
Article
Full-text available
Climate conditions and instantaneous depositional events can influence the relative contribution of sediments from terrestrial and marine environments and ultimately the quantity and composition of carbon buried in the sediment record. Here, we analyze the elemental, isotopic, and organic geochemical composition of marine sediments to identify terr...
Article
Oceanic deoxygenation observed since the 1950s has drawn increasing concern as dissolved oxygen (DO) regulates marine biodiversity and biogeochemical cycles. Yet the DO time series from direct instrumental measurements is insufficiently long (several decades) to constrain the centennial to millennial variability. Here we present redox-sensitive met...
Article
Full-text available
Southern California's Mediterranean‐type hydroclimate is highly variable on interannual time scales due to teleconnected climate forcings such as the El Niño–Southern Oscillation (ENSO). Here we present subannually resolved scanning X‐ray fluorescence Ti counts from deep‐sea cores in Santa Barbara Basin, California, recording 2,000 years of hydrocl...
Article
Full-text available
Sedimentary δ¹⁵N (δ¹⁵Nsed) has been widely applied as a proxy for water column denitrification. When combined with additional productivity proxies, it provides insights into the driving forces behind long‐term changes in water column oxygenation. High‐resolution (~2 years) δ¹⁵Nsed and productivity proxy records (total organic carbon [TOC], Si/Ti, a...
Conference Paper
Impacts of oceanic deoxygenation observed since 1950s have drawn increasing attention as dissolved oxygen regulates biodiversity and biogeochemical cycles. Yet duration of current instrumental records (several decades) is insufficient to constrain natural variability on centennial to millennial time scales. Here we present a redox-sensitive metal (...
Article
Detrital terrestrial sediments preserved in near-shore marine basins bear distinctive geochemical identifiers that can be used to identify the on-shore sediment sources and sediment routing through time. Santa Barbara Basin (SBB), offshore of southern California, USA, contains a well-known, continuous, high-resolution Holocene flood record that can...
Article
Sedimentary redox proxies are usually employed to reconstruct the paleo-redox conditions of bottom water environments, assuming that porewater and bottom water dissolved oxygen concentrations are similar. Using a combination of geochemical and magnetic techniques, we investigate the relationship between iron speciation and mineralogy in recent (~17...
Article
https://deepblue.lib.umich.edu/bitstream/2027.42/148595/1/Tessin_et_al_2019_Geology-Mo_speciation_as_an_important_tool_for_understanding_redox.pdf
Conference Paper
Southern California is ideally situated to investigate impacts of low- and high-latitude teleconnections on oceanic circulation and biogeochemical processes. Located in the mid-latitudes, the California Current System (CCS) is controlled by seasonal displacement of the North Pacific High (NPH) and Aleutian Low (AL), and physically connects the trop...
Article
Molybdenum (Mo) geochemistry is widely used to reconstruct ocean oxygenation throughout Earth's history. However, gaps in our fundamental knowledge of Mo burial within sediments hinder the utility of Mo as a proxy for paleo-redox reconstruction. To improve our understanding of Mo burial pathways and sedimentary Mo speciation, we present combined ge...
Article
The sedimentary record of the Late Cretaceous North American Western Interior Seaway (WIS) is characterized by periods of enhanced organic carbon burial, including an interval that has been identified as Oceanic Anoxic Event (OAE) 3. The timing and duration of this event has proved difficult to constrain, calling into question whether a widespread...
Article
Hydroclimate extremes are expected to become more frequent and intense with anthropogenic climate forcing, but future El Niño-Southern Oscillation (ENSO) behavior is unclear. Understanding of extreme hydroclimate variability and magnitude prior to human-influences is limited by short instrumental records, however, continuous sedimentary archives of...
Poster
Young pelagic, planktivorous fish species off Southern California feed on phytoplankton and zooplankton larvae, which can be related to nutrient delivery by coastal upwelling. Wind-driven coastal upwelling is affected by the position and strength of the North Pacific High pressure system, and therefore is also positively correlated with regional dr...
Article
Full-text available
https://deepblue.lib.umich.edu/bitstream/2027.42/147052/1/acv12421_am.pdf
Article
The center of Santa Barbara Basin (SBB) preserves annual laminations through most of the Holocene providing an important locality for high-resolution late Quaternary paleoclimate and paleoceanography reconstructions. An accurate chronology is necessary for these sediment-based records and enables comparisons with more distal data time-series of sim...
Conference Paper
The short duration of instrumental records limits our understanding of nitrogen loss to denitrification on interannual to centennial time scales. Bulk sediment δ15N is widely applied as a proxy for water column denitrification in oxygen minimum zones (OMZ). Lying within the California OMZ, Santa Barbara Basin (SBB) provides an ideal location for pr...
Article
Understanding dissolved oxygen variability in the ocean is limited by the short duration of direct measurements, however sedimentary oxidation-reduction reactions can provide context for modern observations. Here we use bulk sediment redox-sensitive metal enrichment factors (MoEF, ReEF, and UEF) and scanning X-ray fluorescence (XRF) records to exam...
Article
Glacial benthic δ¹³C and Δ¹⁴C measurements from the Atlantic Ocean have been interpreted to indicate the existence of a poorly ventilated Southern Ocean with greater CO2 and nutrient contents compared to present. Enhanced storage of CO2 in the deep ocean predicts that oxygen concentrations should have declined at the same time—a prediction increasi...
Article
Full-text available
Paleo-redox proxies are crucial for reconstructing past bottom water oxygen concentration changes brought about by ocean circulation and marine productivity shifts in response to climate forcing. Carbonate I/Ca ratios of multiple benthic foraminifera species from ODP Hole 1017E – a core drilled within the Californian oxygen minimum zone (OMZ), on t...
Article
The Late Cretaceous sedimentary record of the North American Western Interior Seaway is characterized by cyclic deposition of organic carbon-rich sediments. One notable interval during the late Coniacian-Santonian is recorded by the Niobrara Formation. The organic carbon-rich interval within the Niobrara Formation has been identified as Oceanic Ano...
Article
Full-text available
We use a new, well-calibrated 500-year paleorecord off southern California to determine collapse frequency, cross-correlation, persistence and return times of exploited forage fish populations. The paleorecord shows that “collapse” (defined as <10% of the mean peak biomass) is a normal state repeatedly experienced by northern anchovy, Pacific hake...
Article
The recurrence and magnitude of southern California hydroclimate extremes are poorly resolved due to the relatively short duration (<140 years) of modern instrumental precipitation and stream gauge records. Terrigenous detrital sediments are often used to reconstruct long-term hydroclimate changes as precipitation increases river runoff and sedimen...
Article
The last 150 years on the California margin have been marked by high variability in precipitation, temperature, sea surface temperature, and ocean chemistry, in response to both natural and anthropogenic changes. Deciphering climate history from ocean sediments is dependent on our understanding of the various influences on marine proxies. Sediment...
Conference Paper
Argon and neodymium isotope geochemistry provide a means of tracking Scabland Flood sediment from source to sink. Analysis of sediment from locations along the flood path and from two marine sediment accumulation sites elucidate patterns of sediment mixing on land, subsequent unmixing at sea, and marine sediment transport pathways. Slackwater depos...
Conference Paper
Flood deposit provenance investigations can be used to identify the sources of sediment eroded during extreme precipitation events, and thus indicate areas likely to be at-risk during future flood events. In southern California, Santa Barbara Basin (SBB) sediment contains a continuous Holocene flood record, and lithologic diversity of catchments di...
Conference Paper
Extreme Southern California weather events include both drought and intense rainfall the elemental composition of Santa Barbara Basin (SBB) sediments records signals of these diverse weather patterns. Extreme precipitation events in the region occur when strong zonal flow brings warm, moist tropical across the Pacific (i.e. ‘atmospheric rivers’). H...
Article
Continental margin sediments are commonly studied using trace metal enrichments as proxies for characterizing their modern redox conditions and tracking past changes in bottom water ventilation and marine primary productivity. Currently little is known about the sedimentary redox history of the continental shelf west of the Antarctic Peninsula. Yet...
Article
Full-text available
Diatom and silicoflagellate assemblages documented in a high-resolution time series spanning 800 to 1600 (AD) in varved sediment recovered in Kasten core SPR0901-02KC (34 16.845 0 N, 120 02.332 0 W, water depth 588 m) from the Santa Barbara Basin (SBB) reveal that SBB surface water conditions during the Medieval Climate Anomaly (MCA) and the early...
Article
Based upon observations from the 20th century, populations of lower trophic level, short-lived fish species are thought to be controlled by large scale oceaneatmosphere circulation shifts. Here, we provide a new 500 year reconstruction of northern anchovy and Pacific sardine fish scale deposition rates (SDRs) and relative abundance from Santa Barba...
Article
Full-text available
A high resolution record of δ 18 O and Mg/Ca-based temperatures spanning 10-50 ka has been reconstructed from the Vancouver margin of the northeastern Pacific Ocean (MD02-2496) from two planktonic foraminiferal species, Neogloboquadrina pachyderma (s.) and Globigerina bulloides. While δ 18 Ocalcite appears synchronous with Dansgaard-Oeschger Inters...
Article
During the Cretaceous, widespread black shale deposition occurred during a series of Oceanic Anoxic Events (OAEs). Multiple processes are known to control the deposition of marine black shales, including changes in primary productivity, organic matter preservation, and dilution. OAEs offer an opportunity to evaluate the relative roles of these forc...
Article
Full-text available
Glacial benthic δ13C and Δ14C measurements from the Atlantic Ocean have been interpreted to indicate the existence of a poorly ventilated Southern Ocean with greater CO2 and nutrient contents compared to present. Enhanced storage of CO2 in the deep ocean predicts that oxygen concentrations should have declined at the same time, although no unequivo...
Data
During the Cretaceous, widespread black shale deposition occurred during a series of Oceanic Anoxic Events (OAEs). Multiple processes are known to control the deposition of marine black shales, including changes in primary productivity, organic matter preservation, and dilution. OAEs offer an opportunity to evaluate the relative roles of these forc...
Article
Full-text available
A new, high-resolution planktonic foraminiferal Mg/Ca-based ocean temperature record has been generated for deep sea core MD02-2496, sited offshore of Vancouver Island, Western Canada during the last deglaciation (21–12 ka). The relationship between Cordilleran Ice Sheet (CIS) retreat and changing regional ocean temperatures has been reconstructed...
Article
Full-text available
Variations in chalcophile and redox-sensitive trace elements are examined at high-resolution intervals from a ~50-kyr long sediment core (MD02-2496) from the Vancouver Island margin. Enrichments of Ag, Cd, Re, U and Mo above lithogenous levels, signifying sedimentary suboxia and anoxia, occurred during the early Holocene and Bølling/Allerød, and du...
Article
Full-text available
Diatom and silicoflagellate assemblages documented in a high-resolution time series spanning 800 to 1600 (AD) in varved sediment recovered in Kasten core SPR0901-02KC (34°16.845′ N, 120°02.332′ W, water depth 588 m) from the Santa Barbara Basin (SBB) reveal that SBB surface water conditions during the Medieval Climate Anomaly (MCA) and the early pa...
Data
Variations in chalcophile and redox-sensitive trace elements are examined at high-resolution intervals from a ~50 kyr long sediment core (MD02-2496) from the Vancouver Island margin. Enrichments of Ag, Cd, Re, U, and Mo above lithogenous levels, signifying sedimentary suboxia and anoxia, occurred during the early Holocene and Bølling/Allerød, and d...
Data
A new, high-resolution planktonic foraminiferal Mg/Ca-based ocean temperature record has been generated for deep sea core MD02-2496, sited offshore of Vancouver Island, Western Canada during the last deglaciation (21-12 ka). The relationship between Cordilleran Ice Sheet (CIS) retreat and changing regional ocean temperatures has been reconstructed...
Article
Full-text available
Sediment in the deep center of the Santa Barbara Basin (SBB) is almost completely laminated for the portion representing the past ∼2000 years and has been utilized as an archive for high-resolution paleoceanography since the 1970s. Unequivocal proof of the presence of varves in SBB sediment throughout the 20th century has been uncritically used to...
Article
Accurate interpretation of paleoproductivity proxies in the Southern Ocean requires "ground truthing" these proxies. Here the concentrations of total Ba, organic carbon (Corg), and biogenic silica (Sibio), along with other redox-sensitive trace metals (Cd, Re, and Mo), are compared with the distribution of silver (Ag) in core top sediments from the...
Article
Santa Barbara Basin (SBB) is well known for producing high quality paleoclimate reconstructions, but the validity of correlations between the basin and other regions rests upon age model accuracy. Yet, the two independent and well-established chronologies based on varve counting and radiocarbon dating do not consistently agree during the last two m...
Article
More negative benthic South Atlantic δ13C values during the last glacial interval suggest increased water column stratification and greater Southern Ocean isolation, supporting the hypothesis that glacial CO2 was stored in the deep Southern Ocean. However, the combined influences of deep water ventilation and the biological pump obscure the mechani...
Article
Full-text available
Size-normalized foraminiferal shell weight has been used as a proxy for past carbonate ion concentration in seawater, assuming that reduced carbonate ion concentration and pH lead to lower calcification rates and lighter, thinner shells. Previous research suggested that the uptake of anthropogenic CO2 and ocean acidification over the last century h...
Article
Santa Barbara Basin is well known for producing high quality paleoclimate reconstructions, however the validity of correlations between climate change recorded in the basin and other regions rests upon the accuracy of age models. Two independent well established chronologies based on varve counting and radiocarbon dates do not agree over the last 2...
Article
Full-text available
Multiproxy data from ODP Hole 1017E (Point Conception, California) provide an excellent opportunity to examine the behavior of barium, within a well-characterized sedimentary system. Bariumexcess is generally considered to be a productivity proxy; however, in nearshore environments, Baexcess records can be compromised by both sediment provenance an...
Article
The Southern Hemisphere westerly winds (SWW) have a major influence over deep ocean ventilation around Antarctica and are modulated by inter-annual and decadal climate variability, such as El Niño-Southern Oscillation (ENSO), Inter-decadal Pacific Oscillation (IPO), and Southern Annular Mode (SAM). Fiordland, New Zealand (44.5-46.5°S), is optimally...
Conference Paper
We present a high-resolution glaciomarine record for MD02-2496 (48°58.5N; 127°02.1W; 1243m water depth), collected from the Vancouver Island continental slope. 46 AMS 14C dates have been generated from both planktonic foraminifera carbonate and bulk sedimentary organic carbon. The presence of two 14C plateaus during deglaciation (~13.3 and ~14.8 14...
Article
High-resolution planktonic foraminiferal census and stable isotope data from a core transect (ODP Site 1017, 893 and 1014) demonstrate remarkable similarities along the Southern California Margin during the last glacial (60–10ka BP). Modern analog technique and δ18O derived sea surface temperatures (SST) demonstrate SST shifts were regionally expre...
Article
Glacial outburst floods (jokulhaups) are important, but poorly understood, drivers of climate change during large-scale deglaciations. Meltwater fluxes are one of the climate forcings with the most uncertain histories included in climate modeling of the last 21 kyr. Outburst flood events are not included in modeled meltwater fluxes due to their sma...