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 alter the geochemical composition of benthic foraminiferal

We use online data assimilation to combine information from a linear inverse model of coupled atmosphere‐ocean dynamics with proxy records to create a new annual‐resolution reconstruction of atmosphere and ocean fields over the last millennium. Instrumental validation of reconstructed sea‐surface temperature and 0–700 m ocean heat content shows broad regions of positive spatial correlations, and high

The Yucatán Peninsula (YP) has a complex hydroclimate with many proposed drivers of interannual and longer‐term variability, ranging from coupled ocean‐atmosphere processes to frequency of tropical cyclones. The mid‐Holocene, a time of higher Northern Hemisphere summer insolation, provides an opportunity to test the relationship between Yucatán Peninsula precipitation and ocean temperature. Here we

The Maldivian archipelago, in the equatorial Indian Ocean, provides a unique location to assess long‐term basin‐wide South Asian Monsoon (SAM) processes as well as its response during climatic extremes. This insight is beneficial to better understand future SAM influences on the Maldives Inner Sea physicochemical characteristics and its diverse tropical ecosystems in a warming world. This study uses

We show that climate and topography control the spatial distribution of stable isotope values on the South Island of New Zealand, based on a spatially dense (n=193) river isotopic survey. Our data show a δ18O minimum in isotope values east of the Southern Alps that demonstrates topographically driven continentality associated with the Southern Alps, which intersect the prevailing, moisture‐laden westerlies

The final stages of evolution of the Himalayan foreland basin (HFB) are preserved in the Siwalik Group of rocks deposited by meandering and/or braided rivers in the western and central regions of HFB. However, the time‐equivalent deposits in the eastern part of the foreland provide contradictory evidence of both terrestrial and marine environments. To address the ambiguity, molecular level characterisation

Carbon isotope (δ13C) records from marine sediments and sedimentary rocks have been extensively used in Cenozoic chemostratigraphy. The early Paleogene interval in particular has received exceptional attention because negative carbon isotope excursions (CIEs) documented in the sedimentary record, for example, at the Paleocene Eocene Thermal Maximum (PETM), ca ∼56 Ma, are believed to reflect significant

Eolian mineral dust is an active agent in the global climate system. It affects planetary albedo and can influence marine biological productivity and ocean‐atmosphere carbon dynamics. This makes the understanding of the global dust cycle crucial for constraining the dust/climate relationship, which requires long‐term dust emission records for all major dust sources. Despite their importance, the sources

The impacts of climate change on north Atlantic nutrient chemistry remain poorly understood, as there exist a multitude of rapidly changing biological and physical drivers of nutrient conditions throughout the region. Here, we present nitrogen isotope measurements derived from a six‐hundred‐year‐old crustose coralline alga (δ15Nalgal) to elucidate historical and contemporary trends in nitrate utilization

The East and South Asian summer monsoons affect billions of people but a multitude of potential variables have precluded definitive attribution of their controlling mechanisms and hindered models of their evolution in an anthropogenically warmed climate. Atmospheric CO2 concentrations were higher than modern during the early Pliocene and provide a potential analog for future climate. Therefore, understanding

No abstract is available for this article.

Modern precipitation over northeastern (NE) South America is strongly controlled by the seasonal meridional migration of the Intertropical Convergence Zone (ITCZ). Ample evidence from the Northern Hemisphere suggests a mid‐ to late Holocene southward migration of the ITCZ. Such a shift would be expected to increase precipitation over semi‐arid northern NE Brazil (Southern Hemisphere). However, the

The regolith hypothesis attributes the inferred growth of a thicker and more voluminous Laurentide Ice Sheet (LIS) across the mid‐Pleistocene transition (MPT) to the removal of softer subglacial substrates of either regolith or sedimentary cover and subsequent exposure of crystalline bedrock with higher basal friction at the base of the LIS. This hypothesis predicts that sediment derived from the LIS

Fire dynamics potentially account for the asynchronous timing of the expansion of C4 grasslands throughout the Mio‐Pliocene world. Yet how fire, climate, and ecosystems interacted in different settings remain poorly constrained because it is difficult to quantify fires and fuel source over these timescales. Here, we apply molecular proxies for fire occurrence alongside records of vegetation change

The northeastern Qinghai‐Tibet Plateau is strongly influenced by the East Asian summer monsoon (EASM), the Indian summer monsoon (ISM) and the westerlies. However, how these various circulation systems interacted in the region during the Holocene, and the nature of the associated environmental impacts, are unclear and even controversial. Here we present a high‐resolution pollen record from Caodalian

The onset, characteristics, and drivers of paleo‐monsoon conditions in East Asia remain a topic of heated debate. Records from the Eocene suggest pronounced rainfall seasonality consistent with monsoon rainfall across China, likely driven by migrations of the Inter‐Tropical Convergence Zone. Model simulations indicate that modern‐like monsoon circulation of China was established by the early Miocene

Modern tropical and subtropical C4 grasslands and savannas were established during the late‐Miocene and Pliocene, over 20 Myr after evolutionary originations of the C4 photosynthetic pathway. This lag suggests environmental factors first limited and then favored C4 plants. Here, we examine the timing and drivers for the establishment of C4 grasslands on the Indian Subcontinent using carbon and hydrogen

The Eocene‐Oligocene transition (EOT) marks the onset of Antarctic glaciation at 33.7 Ma. Although the benthic oxygen isotope record defines the major continental ice sheet expansion, recent sedimentary and geochemical evidence suggests the presence of earlier ephemeral ice sheets. Sediment cores from Ocean Drilling Program Legs 119 and 188 in Prydz Bay provide an archive of conditions in a major drainage

The Early Turonian interval represents a unique confluence of climatic and oceanographic conditions including peak surface temperatures, high greenhouse‐gas concentrations, and maximum Phanerozoic sea level. The susceptibility of this climate mode to astronomical insolation forcing remains poorly understood partly due to a limited time control and unknown phasing of astronomical cycles in this interval

We reconstruct deep water‐mass salinities and spatial distributions in the western North Atlantic during the Last Glacial Maximum (LGM, 19‐26 ka), a period when atmospheric CO2 was significantly lower than it is today. A reversal in the LGM Atlantic meridional bottom water salinity gradient has been hypothesized for several LGM water‐mass reconstructions. Such a reversal has the potential to influence

During the last deglaciation abrupt millennial‐scale perturbations of the Atlantic Meridional Overturning Circulation massively altered the interhemispheric heat distribution affecting e.g. continental ice volume and hydroclimate. If and how the related cross‐equatorial heat transport was controlled by the interplay between the southward‐flowing Brazil Current (BC) and northward‐flowing North Brazil

Conventional magnetofossils represent magnetic mineral remains of magnetotactic bacteria. Giant magnetofossils have no known modern analog. Both conventional and giant magnetofossil assemblages can record paleoenvironmental information through changes in magnetotactic bacteria diversity driven by nutrient supply and oxygenation. We use marine sediments that record a rapid global warming event, the

Bulk sediment δ15N records from the eastern tropical Pacific (ETP) extending back to the last ice age most often show low glacial δ15N, then a deglacial δ15N maximum, followed by a gradual decline to a late Holocene δ15N that is typically higher than that of the Last Glacial Maximum (LGM). The lower δ15N of the LGM has been interpreted to reflect an ice age reduction in water column denitrification

Here we use volume density (ρV) measurements as a metric of size‐normalized weights for Neogloboquadrina pachyderma, a planktonic foraminifer, from upper OMZ and abyssal depth sites in the Gulf of Alaska over the past ∼20,000 years to test for covariation between carbonate preservation and OMZ intensity. We find that dissolution of N. pachyderma is most intense at the upper OMZ site where oxygenation

Trace elements in a speleothem have been considered to be effective proxies to characterize hydroclimatic changes. In this study, we present speleothem trace element records of the penultimate glacial‐interglacial transition from 138 to 125.8 ka BP from the Shangxiaofeng cave in northeastern China. We used two analytical methods, namely, inductively coupled plasma optical emission spectrometry (ICP‐OES)

Variations in Mediterranean thermohaline circulation of the Quaternary are still not well constrained whereas they have been considered to have an influence on the Atlantic Meridional Overturning Circulation and on the oxygenation of waters in the deep basins of the Mediterranean Sea. εNd analyses have been carried out on planktonic foraminifera of cores collected in the central Mediterranean Sea to

The Humboldt Current System (HCS) is characterized by high marine primary productivity, the dynamics of which are closely linked to climate variability. However, its changes beyond the last glacial cycle are virtually unknown due to a dearth of long sediment records. Here, we present a 500 ka multi‐proxy marine productivity reconstruction from the southernmost part of the HCS (∼43 S). At these latitudes

Anthropogenic climate change has significant impacts at the ecosystem scale including widespread drought, flooding, and other natural disasters related to precipitation extremes. To contextualize modern climate change, scientists often look to ancient climate changes, such as shifts in ancient precipitation ranges. Previous studies have used fossil leaf organic geochemistry and paleosol inorganic chemistry

Mineral dust particles from different source regions typically have distinct Pb isotope ratios. Theoretically, Pb isotopic composition of terrigenous minerals isolated from open‐ocean sediments should allow for dust provenance reconstructions. However, Pb isotopes of terrigenous fractions of sediments have frequently been inconsistent with expected source region signatures. This study investigates

Once a year we take the opportunity to thank the reviewers whose difficult, important work is never sufficiently recognized. This year is special. Due to the vicissitudes of COVID19, submissions were up just as reviewing came at a higher personal cost than ever before. Reviewers had to dig deep and make real sacrifices to respond to the community's needs for critical, thorough reviews aiming to improve

Upwelling within the Eastern Equatorial Pacific (EEP) Ocean is a key factor for the Earth's climate because it supports >10% of the present‐day biological production. The dynamics of upwelling in the EEP across the Plio‐Pleistocene transition—an interval particularly relevant for understanding near‐future warming due to Anthropocene‐like atmospheric carbon‐dioxide levels—have been intensively studied

Sedimentary specimens of the planktonic foraminifera Globorotalia inflata can provide information on subsurface conditions of past oceans. However, interpretation of their geochemical signal is complicated by possible effects of cryptic diversity and encrustation. Here we address these issues using plankton tow and sediment samples from the western South Atlantic, where two genotypes of G. inflata

The Arctic hydrological cycle is predicted to intensify as the Arctic warms, due to increased poleward moisture transport during summer and increased evaporation from seas once ice‐covered during winter. Records of past Arctic precipitation seasonality are important because they provide a context for these ongoing changes. In some Arctic lakes, stable isotopes of oxygen and hydrogen (δ18O and δ2H,

The El Niño–Southern Oscillation (ENSO) dominates interannual climate variability worldwide and has important environmental and socio‐economic consequences. However, determining the evolution of ENSO variability and its long‐term response to climate forcing remains an ongoing challenge owing to the limited instrumental records. In this study, we quantified ENSO variability via an empirically calibrated

Coral geochemical climate reconstructions can extend our knowledge of global climate variability and trends over time scales longer than those of instrumental data. However, such reconstructions can be biased by coral growth and skeletal architecture, such as growth troughs, off‐axis corallite orientation, and changing growth direction. This study quantifies the impact of skeletal architecture and

The Paleocene‐Eocene Thermal Maximum (PETM; 56 Ma) is considered to be one of the best analogs for future climate change. The carbon isotope composition (δ13C) of n‐alkanes derived from leaf waxes of terrestrial plants and marine algae can provide important insights into the carbon cycle perturbation during the PETM. Here, we present new organic geochemical data and compound‐specific δ13C data from

The Miocene epoch, spanning 23.03‐5.33Ma, was a dynamic climate of sustained, polar amplified warmth. Miocene atmospheric CO2 concentrations are typically reconstructed between 300‐600ppm and were potentially higher during the Miocene Climatic Optimum (16.75‐14.5Ma). With surface temperature reconstructions pointing to substantial midlatitude and polar warmth, it is unclear what processes maintained

Large volcanic eruptions are one of the dominant perturbations to global and regional atmospheric temperatures on timescales of years to decades. Discrepancies remain, however, in the estimated magnitude and persistence of the surface temperature cooling caused by volcanic eruptions, as characterized by paleoclimatic proxies and climate models. We investigate these discrepancies in the context of large

Magnetic signals in deep‐sea sediments have the potential to unravel past continental environmental changes, via changes in primary terrigenous magnetic supply, but also record past marine environmental conditions, via in situ formation of secondary magnetic minerals, particularly when complemented by independent proxies. By combining environmagnetic, geochemical, and siliciclastic grain size data

No abstract is available for this article.

The development of larger and longer‐lasting northern hemisphere ice sheets during the Mid Pleistocene Transition (MPT) coincided with global cooling. Here we show that surface waters of the north‐eastern Atlantic actually warmed across this interval (∼1.2‐0.8Ma), which we argue reflects an increase in the north‐eastward transport of heat and moisture via the North Atlantic Current (NAC) into the Nordic

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 in remineralization deeper in the water column in

The upper branch of the Atlantic meridional overturning circulation (AMOC) plays a critical role in ocean circulation and climate change, yet its variability during the last glacial period is poorly documented. Here, we investigate the northward‐flowing Glacial Eastern Boundary Current (GEBC) in the North Atlantic, known today as the European Slope Current, and representing the easternmost portion

We traced diatom composition and diversity through time using diatom derived sedimentary ancient DNA (sedaDNA) from eastern continental slope sediments off Kamchatka (North Pacific) by applying a short, diatom‐specific marker on 63 samples in a DNA metabarcoding approach. The sequences were assigned to diatoms that are common in the area and characteristic of cold water. SedaDNA allowed us to observe

Coccolithophores, common primary producers in Mesozoic, Cenozoic, and present oceans, are significant components of the earth’s biogeochemical cycles. Being the most productive calcifying organism on earth, their carbonate oozes play a major role in fixing CO2, thereby forming the most important long‐term CO2 sink throughout the last 100 Ma. Our understanding of their fossil ancestors is mainly based

RI‐OH′ and RI‐OH (ring index of hydroxylated tetraethers) are two novel organic paleothermometers which could either complement or replace more established paleothermometric proxies, such as UK′37 (C37 ketone unsaturation ratio) and TEX86 (TetraEther indeX of tetraethers consisting of 86 carbon atoms). Despite a few promising attempts, the paleothermometric potential of RI‐OH′ and RI‐OH is not fully

Efforts to understand long‐term Indian Ocean dynamics and land‐sea linkages in southeast Africa during periods of significant global and regional climate change have been inhibited by a lack of high‐resolution climate records, particularly during the Plio‐Pleistocene. Here we present new biomarker and pollen records from International Ocean Discovery Program (IODP) Site U1478, located at the Upper

Remnants of shooting stars are preserved in form of cosmic spherules in ice and sediments. The extraterrestrial material is heated and melted upon atmospheric entry and is collected at the Earth's surface as cosmic spherules. A fraction of cosmic spherules (I‐type cosmic spherules) sources from extraterrestrial Fe,Ni metal. These metal particles melt and become oxidized in the atmosphere. The oxygen

A new orbital‐scale record of bulk sediment biogenic silica (opal) content from Ocean Drilling Program (ODP) Site 745B spans the past 630 kyr (Marine Isotope Stages (MIS) 1–16). Together with the published portion of the record (MIS 16–31, Billups et al., 2018), we obtain a 1 million year orbital‐scale record of paleoproductivity in the Antarctic Zone of the Indian Ocean sector of the Southern Ocean

The development of the South Asian monsoon (SAM) and Himalaya‐Tibetan Plateau uplift were closely intertwined with some studies suggesting that uplift initiated the monsoon whereas others link tectonics with monsoon‐controlled exhumation. Silicate weathering controls atmospheric CO2 on geological timescales resulting in a large potential for monsoon strength and the Himalayan orogeny to influence global

The mid Miocene represents an important target for paleoclimatic study because the atmospheric CO2 concentration ranged from near modern values to ∼800 ppm, while a large, dynamic Antarctic ice sheet was likely to have been present throughout much of this interval. In this special issue, Modestou et al. (2020) (doi.org/10.1029/2020PA003927) reconstruct deep ocean warmth based on the clumped isotopic

Sedimentary records of past hurricane activity indicate centennial‐scale periods over the past millennium with elevated hurricane activity. The search for the underlying mechanism behind these active hurricane periods is confounded by regional variations in their timing. Here, we present a new high resolution paleohurricane record from The Bahamas with a synthesis of published North Atlantic records

The evolution of the East Asian Summer Monsoon (EASM) and its mechanism since the Holocene remains controversial. Here, we investigate four eolian sediment sequences in the Lake Qinghai Basin (LQB), Northeastern Tibetan Plateau (NETP), in the marginal zone of the modern EASM. The results indicate that paleoclimatological interpretation of the color parameters and CaCO3 in eolian sand‐paleosol sequence

The mid‐to‐late Miocene is proposed as a key interval in the transition of the Earth's climate state toward that of the modern‐day. However, it remains a poorly understood interval in the evolution of Cenozoic climate, and the sparse proxy‐based climate reconstructions are associated with large uncertainties. In particular, tropical sea surface temperature (SST) estimates largely rely on the unsaturated

A high‐resolution carbonate C‐isotope stratigraphy for the Aptian is presented for the Cau core (Spain). The biostratigraphically calibrated C‐isotope stratigraphy of the core is used to refine the previously defined C‐isotope segments of the Aptian. Thirteen C‐isotope segments have been identified and correlated, and further subdivisions are presented. Correlation with other sections worldwide demonstrates

Asian mineral dust has been studied extensively for its role in affecting regional‐to global‐scale climate and for its deposits, which enable reconstructing Asian atmospheric circulation in the past. However, the timing and origin of the dust deposits remain debated. Numerous loess records have been reported across the Asian continent with ages varying from the Miocene to the Eocene and linked to various

No abstract is available for this article.

The Eocene Epoch corresponds to the runup toward the Greenhouse to Icehouse Cenozoic transition. To fully appreciate this climate evolution, detailed and accurate age‐depth models are required. While much progress has been made recently in the field of Eocene astrochronology, the construction of unambiguous Eocene astronomical timescales (ATS) is hampered by lithologically undetected hiatuses, the

Individual foraminiferal analysis (IFA) has proven to be a useful tool in reconstructing the amplitude of high‐frequency climate signals such as the annual cycle and the El Niño‐Southern Oscillation (ENSO). However, using IFA to evaluate past changes in climate variability is complicated by many factors including geographic location, foraminiferal ecology, methods of sample processing, and the influence

Wind dynamics in dust source areas are influenced by climate change on both regional and global scales. Northeastern arid central Asia is one of the most important sources of Asian dust. We conducted grain size analyses of the extracted quartz component of bulk samples from four Holocene aeolian sedimentary sequences in northeastern arid central Asia, in order to reconstruct variations in strength