A5061556004- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Geological formations and processes
- Pleistocene-Era Hominins and Archaeology
- Cryospheric studies and observations
- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Paleontology and Stratigraphy of Fossils
- Geophysics and Gravity Measurements
- Marine and environmental studies
- Hydrocarbon exploration and reservoir analysis
- Spacecraft and Cryogenic Technologies
- Astronomical Observations and Instrumentation
- Geological and Geophysical Studies
- Marine Biology and Ecology Research
- earthquake and tectonic studies
- Polar Research and Ecology
- Reservoir Engineering and Simulation Methods
- Offshore Engineering and Technologies
- Planetary Science and Exploration
- Atmospheric and Environmental Gas Dynamics
- Drilling and Well Engineering
- Geological and Geochemical Analysis
- Marine animal studies overview
Lamont-Doherty Earth Observatory
2015-2024
Columbia University
2015-2024
United States Office of Personnel Management
2021
Sam Houston State University
2021
University of Plymouth
2021
Geological Survey of Western Australia
2021
Tongji University
2021
Discovery Place
2021
Texas A&M University
1987-2021
Oregon State University
2020
We present a 5.3‐Myr stack (the “LR04” stack) of benthic δ 18 O records from 57 globally distributed sites aligned by an automated graphic correlation algorithm. This is the first composed more than three to extend beyond 850 ka, and we use its improved signal quality identify 24 new marine isotope stages in early Pliocene. also LR04 age model for Pliocene‐Pleistocene derived tuning simple ice based on 21 June insolation at 65°N. Stacked sedimentation rates provide additional constraints...
Climate over the past million years has been dominated by glaciation cycles with periods near 23,000, 41,000, and 100,000 years. In a linear version of Milankovitch theory, two shorter can be explained as responses to insolation driven precession obliquity. But 100,000‐year radiation cycle (arising from eccentricity variation) is much too small in amplitude late phase produce corresponding climate direct forcing. We present observations showing that geographic progression local similar other...
Time series of ocean properties provide a measure global ice volume and monitor key features the wind‐driven density‐driven circulations over past 400,000 years. Cycles with periods near 23,000, 41,000, 100,000 years dominate this climatic narrative. When narrative is examined in geographic array time series, phase each oscillation seen to progress through system essentially same sequence all three cycles. We argue that 23,000‐ 41,000‐year cycles glaciation are continuous, linear responses...
Paleoclimate data show that climate sensitivity is ~3°C for doubled CO 2 , including only fast feedback processes. Equilibrium sensitivity, slower surface albedo feedbacks, ~6°C the range of states between glacial conditions and ice-free Antarctica. Decreasing was main cause a cooling trend began 50 million years ago, planet being nearly until fell to 450 ± 100 ppm; barring prompt policy changes, critical level will be passed, in opposite direction, within decades. If humanity wishes...
Research Article| July 01, 1988 Influence of late Cenozoic mountain building on ocean geochemical cycles Maureen E. Raymo; Raymo 1Lamont-Doherty Geological Observatory and Department Sciences, Columbia University, Palisades, New York 10964 Search for other works by this author on: GSW Google Scholar William F. Ruddiman; Ruddiman Philip N. Froelich Geology (1988) 16 (7): 649–653. https://doi.org/10.1130/0091-7613(1988)016<0649:IOLCMB>2.3.CO;2 Article history first online: 02 Jun 2017 Cite...
We analyze five high‐resolution time series spanning the last 1.65 m.y.: benthic foraminiferal δ 18 O and 13 O, percent CaCO 3 , estimated sea surface temperature (SST) at North Atlantic Deep Sea Drilling Project site 607 609. Each record is a multicore composite verified for continuity by splicing among multiple holes. These climatic indices portray changes in northern hemisphere ice sheet size deep circulation. By tuning obliquity precession components to orbital variations, we have...
High‐resolution records of δ 18 O, 13 and percent CaCO 3 from the late Pliocene North Atlantic (Deep Sea Drilling Project sites 607 609) are presented oxygen isotope stages formalized back to stage 116 at 2.73 Ma. From 2.8 1.6 Ma, interval studied, variations in these were dominated by 41‐kyr component orbital obliquity. Significant variation frequencies eccentricity (96‐kyr) precession (23‐kyr) observed O record between 2.1 but not before. Prior 2.4 Ma (stage 100), suggest ice sheet growth...
Research Article| November 01, 1995 Late Neogene chronology: New perspectives in high-resolution stratigraphy W. A. Berggren; Berggren 1Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Hole, Massachusetts 02543 Search for other works by this author on: GSW Google Scholar F. J. Hilgen; Hilgen C. G. Langereis; Langereis D. V. Kent; Kent Obradovich; Obradovich Isabella Raffi; Raffi M. E. Raymo; Raymo N. Shackleton Author Article Information Publisher: Geological...
A simple, untuned “constant sedimentation rate” timescale developed using three radiometric age constraints and eleven δ 18 O records longer than 0.8 Myr provides strong support for the validity of SPECMAP late Quaternary [ Imbrie et al., 1984]. In particular, present study independently confirms link between major deglaciations (terminations) increases in northern hemisphere summer radiation at high latitudes shows that this correlation is not an artifact orbital tuning. addition, excess...
We propose that from ∼3 to 1 million years ago, ice volume changes occurred in both the Northern and Southern Hemispheres, each controlled by local summer insolation. Because Earth's orbital precession is out of phase between hemispheres, 23,000-year hemisphere cancel globally integrated proxies such as ocean δ 18 O or sea level, leaving in-phase obliquity (41,000 years) component insolation dominate those records. Only a modest mass change Antarctica required effectively much larger...
Carbonatites are igneous rocks formed in the crust by fractional crystallization of carbonate-rich parental melts that mostly mantle derived. They dominantly consist carbonate minerals such as calcite, dolomite, and ankerite, well minor ...Read More
Five δ 13 C records from the deep ocean, extending back to 1.3 Ma, were examined in order constrain changes mean ocean carbon isotope composition and thermohaline circulation over 41‐ 100‐ka climate transition. These data show that significant perturbations chemistry associated with mid‐Pleistocene Notable features of last Myr are (1) a pronounced ∼0.3‰ decrease between 0.9 1.0 Myr, followed by return pre‐1.0 Ma values 400 ka B.P., which we propose was due onetime addition isotopically...
For most of the Northern Hemisphere Ice Ages, from ∼3.0 to 0.8 m.y., global ice volume varied predominantly at 41,000 year period Earth's orbital obliquity. However, summer (or caloric half year) insolation high latitudes, which is widely believed be major influence on high‐latitude climate and volume, dominated by 23,000 precessional period. Thus geologic record poses a challenge our understanding dynamics. Here we propose that variations in gradient between low latitudes control during...
Unraveling the dynamics of Northern Hemisphere glaciation (NHG) in Pliocene is a key step toward quantitative theory climate transition from greenhouse to an icehouse world. Extracting ice volume signal marine oxygen isotope (δ 18 O) records corrupted with “temperature noise” can be accomplished using statistical time series analysis. We use 45 δ O benthic and planktonic foraminifera globally distributed sites reconstruct NHG initiation. compare amplitudes those temperature proxy estimate...
We provide the first continuous, orbital‐resolution sea surface temperature (SST) record from high‐latitude North Atlantic, a region critical to understanding origin of Plio‐Pleistocene ice ages and proximal regions that became frequently glaciated after ∼2.7 Ma. analyzed sediments Ocean Drilling Program Site 982 over last 4 Ma for their alkenone unsaturation index compared this water signal benthic δ 18 O obtained same section. find while ocean temperatures were significantly warmer (∼6°C)...