scholarly journals Cenozoic carbonate burial along continental margins

Geology ◽  
2019 ◽  
Vol 47 (11) ◽  
pp. 1025-1028 ◽  
Author(s):  
Robin van der Ploeg ◽  
Bernard P. Boudreau ◽  
Jack J. Middelburg ◽  
Appy Sluijs
Keyword(s):  
Sea Level ◽  
Middle Miocene ◽  
Carbon Sink ◽  
Global Climate ◽  
Continental Margins ◽  
Marine Carbonate ◽  
Major Increase ◽  
Continental Weathering ◽  
Climate Transition

Abstract Marine carbonate burial represents the largest long-term carbon sink at Earth’s surface, occurring in both deep-sea (pelagic) environments and shallower waters along continental margins. The distribution of carbonate accumulation has varied over geological history and impacts the carbon cycle and ocean chemistry, but it remains difficult to quantitatively constrain. Here, we reconstruct Cenozoic carbonate burial along continental margins using a mass balance for global carbonate alkalinity, which integrates independent estimates for continental weathering and pelagic carbonate burial. Our results indicate that major changes in marginal carbonate burial were associated with important climate and sea-level change events, including the Eocene-Oligocene transition (ca. 34 Ma), the Oligocene-Miocene boundary Mi-1 glaciation (ca. 23 Ma), and the middle Miocene climate transition (ca. 14 Ma). In addition, we find that a major increase in continental weathering from ca. 10 Ma to the present may have driven a concomitant increase in pelagic carbonate burial. Together, our results show that changes in global climate, sea level, and continental weathering have all impacted carbonate burial over the Cenozoic, but the relative importance of these processes may have varied through time.

scholarly journals Boundary conditions for the Middle Miocene Climate Transition (MMCT v1.0)

2017 ◽  
Author(s):  
Amanda Frigola ◽  
Matthias Prange ◽  
Michael Schulz
Keyword(s):  
Boundary Conditions ◽  
General Circulation ◽  
Middle Miocene ◽  
Climate Models ◽  
Global Climate ◽  
Co2 Concentration ◽  
General Circulation Models ◽  
Global Climate Models ◽  
Ice Volume ◽  
Climate Transition

Abstract. The Middle Miocene Climate Transition was characterized by major Antarctic ice-sheet expansion and global cooling during the interval ~ 15–13 Ma. Here we present two sets of boundary conditions for global general circulation models characterizing the periods before (Middle Miocene Climatic Optimum; MMCO) and after (Middle Miocene Glaciation; MMG) the transition. These boundary conditions include Middle Miocene global topography, bathymetry and vegetation. Additionally, Antarctic ice volume and geometry, sea-level and atmospheric CO2 concentration estimates for the MMCO and the MMG are reviewed. The boundary-condition files are available for use as input in a wide variety of global climate models and constitute a valuable tool for modeling studies with a focus on the Middle Miocene.

scholarly journals The carbon sink of tropical seasonal forests in southeastern Brazil can be under threat

2020 ◽  
Vol 6 (51) ◽  
pp. eabd4548
Author(s):  
Vinícius Andrade Maia ◽  
Alisson Borges Miranda Santos ◽  
Natália de Aguiar-Campos ◽  
Cléber Rodrigo de Souza ◽  
Matheus Coutinho Freitas de Oliveira ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Carbon Sink ◽  
Global Climate ◽  
Carbon Sources ◽  
Southeastern Brazil ◽  
Forest Sites ◽  
Tropical Seasonal Forest ◽  
Terrestrial Carbon Sink ◽  
Seasonal Forests

Tropical forests have played an important role as a carbon sink over time. However, the carbon dynamics of Brazilian non-Amazon tropical forests are still not well understood. Here, we used data from 32 tropical seasonal forest sites, monitored from 1987 to 2020 (mean site monitoring length, ~15 years) to investigate their long-term trends in carbon stocks and sinks. Our results highlight a long-term decline in the net carbon sink (0.13 Mg C ha−1 year−1) caused by decreasing carbon gains (2.6% by year) and increasing carbon losses (3.4% by year). The driest and warmest sites are experiencing the most severe carbon sink decline and have already moved from carbon sinks to carbon sources. Because of the importance of the terrestrial carbon sink for the global climate, policies are needed to mitigate the emission of greenhouse gases and to restore and protect tropical seasonal forests.

scholarly journals Discovery of the Badenian evaporites inside the Carpathian Arc: implications for global climate change and Paratethys salinity

2017 ◽  
Vol 68 (3) ◽  
pp. 193-206 ◽  
Author(s):  
Katalin Báldi ◽  
Felicitász Velledits ◽  
Stjepan Ćorić ◽  
Viktor Lemberkovics ◽  
Katalin Lőrincz ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Normal Saline ◽  
Middle Miocene ◽  
Global Climate ◽  
Great Plain ◽  
Geological Record ◽  
Central Paratethys ◽  
Growing Body ◽  
Climate Transition

Abstract Massive evaporites were discovered in the Soltvadkert Trough (Great Plain, Hungary) correlating to the Badenian Salinity Crisis (13.8 Ma, Middle Miocene) on the basis of nannoplankton and foraminifera biostratigraphy. This new occurrence from Hungary previously thought to be devoid of evaporites is part of a growing body of evidence of evaporitic basins inside the Carpathian Arc. We suggest the presence of evaporites perhaps in the entire Central Paratethys during the salinity crisis. Different scenarios are suggested for what subsequently happened to these evaporites to explain their presence or absence in the geological record. Where they are present, scenario A suggests that they were preserved in subsiding, deep basins overlain by younger sediments that protected the evaporites from reworking, like in the studied area. Where they are absent, scenario B suggests recycling. Scenario B explains how the supposedly brackish Sarmatian could have been hyper/normal saline locally by providing a source of the excess salt from the reworking and dissolving of BSC halite into seawater. These scenarios suggest a much larger amount of evaporites locked up in the Central Paratethys during the salinity crisis then previously thought, probably contributing to the step-like nature of cooling of the Mid Miocene Climate Transition, the coeval Mi3b.

Fifty years of Marine and Freshwater Research

1999 ◽  
Keyword(s):  
Coral Reefs ◽  
Sea Level ◽  
Climate Changes ◽  
Sea Water ◽  
Global Climate ◽  
Short Term ◽  
Natural Factors ◽  
Carbon Dioxide Concentrations ◽  
Minimal Damage

Factors causing global degradation of coral reefs are examined briefly as a basis for predicting the likely consequences of increases in these factors. The earlier consensus was that widespread but localized damage from natural factors such as storms, and direct anthropogenic effects such as increased sedimentation, pollution and exploitation, posed the largest immediate threat to coral reefs. Now truly global factors associated with accelerating Global Climate Change are either damaging coral reefs or have the potential to inflict greater damage in the immediate future: e.g. increases in coral bleaching and mortality, and reductions in coral calcification due to changes in sea-water chemistry with increasing carbon dioxide concentrations. Rises in sea level will probably disrupt human communities and their cultures by making coral cays uninhabitable, whereas coral reefs will sustain minimal damage from the rise in sea level. The short-term (decades) prognosis is indeed grim, with major reductions almost certain in the extent and biodiversity of coral reefs, and severe disruptions to cultures and economies dependent on reef resources. The long-term (centuries to millennia) prognosis is more encouraging because coral reefs have remarkable resilience to severe disruption and will probably show this resilience in the future when climate changes either stabilize or reverse.

VARIATIONS OF SEA LEVEL AND GLOBAL CLIMATE IN MODERN CONDITIONS

2017 ◽  
Author(s):  
Valeriy Malinin ◽  
Valeriy Malinin ◽  
Svetlana Gordeeva ◽  
Svetlana Gordeeva ◽  
Oleg Shevchuk ◽  
...  
Keyword(s):  
Statistical Model ◽  
Sea Level ◽  
Air Temperature ◽  
Global Climate ◽  
Linear Trend ◽  
Initial Information ◽  
Ipcc Report ◽  
Interannual Fluctuations ◽  
First Time

Global warming can result in the rise of Sea Level (SL) by 40–100 cm by the end of the XXI century with possible catastrophic consequences for coastal zone. Study and prediction of long-term fluctuations of sea level is among the most important problems of modern hydrometeorology. A series of studies of SL interannual fluctuations have been carried out in RSHU. A reconstruction of SL fluctuations during the observation period of 1861-2010, i.e. 150 years, was performed on the basis of the developed statistical model showing a powerful linear trend describing 94% of the initial row dispersion. During the XX century the trend approached 1.8 mm/year. The comparison of actual and calculated SL trends for two periods (1980–2005 and 1993-2003) has shown that the residual error makes respectively 0.21 and 0.22 mm/year that is three times less, than in the Fourth IPCC report. Also, for the first time the complex of methods of SL longterm forecast was developed: the main advantage of a simple statistical model of SL longterm forecast is a minimum of initial information, but the model accuracy is comparable with complex and expensive ocean and atmosphere circulation models. The two-decade range physical-statistical sea level prediction model was developed for the first time based on the idea that Global Air Temperature (GAT) is a major factor of SL changes. It was experimentally shown that there is a long delay (20 and 30 years) of SL fluctuations with respect to Global Air Temperature.

MIOCENE NERITIC BENTHIC FORAMINIFERAL COMMUNITY DYNAMICS, CALVERT CLIFFS, MARYLAND, USA: SPECIES POOL, PATTERNS AND PROCESSES

Palaios ◽  
2021 ◽  
Vol 36 (7) ◽  
pp. 247-259
Author(s):  
STEPHEN J. CULVER ◽  
SETH R. SUTTON ◽  
DAVID J. MALLINSON ◽  
MARTIN A. BUZAS ◽  
MARCI M. ROBINSON ◽  
...  
Keyword(s):  
Sea Level ◽  
Benthic Foraminifera ◽  
Middle Miocene ◽  
Community Dynamics ◽  
Abundant Species ◽  
Common Species ◽  
Species Pool ◽  
Regional Species Pool ◽  
Patterns And Processes ◽  
Climate Transition

ABSTRACT The presence/absence and abundance of benthic foraminifera in successive discrete beds (Shattuck “zones”) of the Miocene Calvert and Choptank formations, exposed at the Calvert Cliffs, Maryland, USA, allows for investigation of community dynamics over space and time. The stratigraphic distribution of benthic foraminifera is documented and interpreted in the context of sea-level change, sequence stratigraphy, and the previously published distribution of mollusks. Neritic benthic foraminiferal communities of four sea-level cycles over ∼4 million years of the middle Miocene, encompassing the Miocene Climatic Optimum and the succeeding middle Miocene Climate Transition, are dominated by the same abundant species. They differ in the varying abundance of common species that occur throughout most of the studied section and in the different rare species that appear and disappear. Transgressive systems tracts (TSTs) have higher species diversity than highstand systems tracts (HSTs) but much lower density of specimens. In contrast to some previous research, all beds in the studied section are interpreted as being from the inner part of a broad, low gradient shelf and were deposited at water depths of less than ∼50 m. It is suggested that species are recruited from a regional species pool of propagules throughout the duration of TSTs. Recruitment is curtailed during highstands leading to lower diversity in the HSTs.

scholarly journals Timing of the Middle Miocene Badenian Stage of the Central Paratethys

2014 ◽  
Vol 65 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Johann Hohenegger ◽  
Stjepan Ćorić ◽  
Michael Wagreich
Keyword(s):  
Sea Level ◽  
Middle Miocene ◽  
Planktonic Foraminifera ◽  
Sea Level Changes ◽  
Vienna Basin ◽  
Central Paratethys ◽  
Polarity Reversals ◽  
Global Events ◽  
Geomagnetic Polarity ◽  
Climate Transition

Abstract A new and precisely defined chronometric subdivision of the Badenian (Middle Miocene, regional stage of Central Paratethys) is proposed. This uses global events, mainly geomagnetic polarity reversals as correlated chronometric boundaries, supported by climatic and sea-level changes in addition to isotope events and biostratigraphic data. The Karpatian/ Badenian boundary lies at 16.303 Ma, at the top of Chron C5Cn.2n, which is near the base of the Praeorbulina sicana Lowest-occurrence Zone (LOZ). The Badenian/Sarmatian boundary is placed at the top of polarity Chron C5Ar.2n, thus at 12.829 Ma. In relation to three sea level cycles TB 2.3, TB 2.4 and TB 2.5 and astronomically confirmed data, the Badenian can be divided into three parts of nearly equivalent duration. The Early Badenian as newly defined here ranges from 16.303 to 15.032 Ma (top of polarity Chron C5Bn.2n). The younger boundary correlates roughly to the base of the planktonic foraminifera Orbulina suturalis LOZ at 15.10 Ma, the HO (Highest Occurrence) of the nannofossil Helicosphaera ampliaperta at 14.91 Ma (NN4/NN5 boundary) and the Lan2/Ser1 sequence boundary at 14.80 Ma. The subsequent Mid Badenian ranges from 15.032 Ma to 13.82 Ma; the latter datum correlates with the base of the Serravallian, characterized by a strong global cooling event reflected in the oxygen isotope event Mi3b. The main part of cycle TB 2.4 falls into the Mid Badenian, which can be subdivided by a short cooling event at 14.24 Ma during the Middle Miocene Climate Transition (14.70 to 13.82 Ma). The HCO (Highest common occurrence) of the nannofossil Helicosphaera waltrans at 14.357 Ma supports this division, also seen in the tropical plankton Zones M6 Orbulina suturalis LOZ and M7 Fohsella peripheroacuta LOZ that correspond roughly to the lower and upper Lagenidae zones in the Vienna Basin, respectively. The Late Badenian is delimited in time at the base to 13.82 Ma by the Langhian/Serravallian boundary and at the top by the top of polarity Chron C5Ar.2n at 12.829 Ma. The Mediterranean Langhian/Serravallian boundary can be equated with the Mid/Late Badenian boundary at 13.82 Ma. However, the Karpatian/Badenian boundary at 16.303 Ma, a significant event easily recognizable in biostratigraphy, paleoclimate evolution and sequence stratigraphy, cannot be equated with the proposed global Burdigalian/Langhian, and thus Early/Middle Miocene boundary, at 15.974 Ma

Spatial and temporal evolution of Cenozoic carbonate platforms on the continental margins of the South China Sea: Response to opening of the ocean basin

2016 ◽  
Vol 4 (3) ◽  
pp. SP1-SP19 ◽  
Author(s):  
Shiguo Wu ◽  
Xinyuan Zhang ◽  
Zhen Yang ◽  
Tuoyu Wu ◽  
Jinwei Gao ◽  
...  
Keyword(s):  
South China Sea ◽  
Sea Level ◽  
South China ◽  
Late Miocene ◽  
Tectonic Evolution ◽  
Middle Miocene ◽  
Ocean Basin ◽  
Continental Margins ◽  
Carbonate Platforms ◽  
Relative Sea Level

Widespread and tremendously thick Cenozoic carbonate sequences are present along the margins of the South China Sea (SCS). However, most of the sequences have been drowned since the Late Miocene. The stratigraphic architecture of the carbonate platforms in the SCS can provide information on the tectonic evolution of the ocean basin. Based on 2D/3D seismic, well and regional geologic data, we have interpreted the Cenozoic SCS carbonate platforms along the continental margins. The carbonate platforms developed during rifting and initiated on the fault block of the conjugate rifted margins. Most of the carbonate platforms became drowned after the Middle Miocene. The Malampaya Carbonate Sequences, which have thicknesses of greater than 600 m, developed on a horst of an Oligocene rifted block. Tectonic subsidence provided accommodation for the growth of the carbonate platforms. Tectonic tilting, faulting, and the foreland bulge controlled the distributions, thicknesses, and horizontal seismic reflection variations of the drowned carbonate platforms. The tectonic evolution and relative sea-level fluctuations controlled the depositional cycles of the carbonate platforms. We quantitatively calculated the factors that affected the extension and subsidence rates using balanced cross section and backstepping techniques. Our results have demonstrated that the carbonate platforms flourished during the Middle Miocene due to stable tectonic conditions and shrank during the Late Miocene due to rapid subsidence. The relative sea level exerted a second-order control on the evolutionary trend of the carbonate platforms and a third-order control on the evolutionary periods in each stage.

scholarly journals Boundary conditions for the Middle Miocene Climate Transition (MMCT v1.0)

2018 ◽  
Vol 11 (4) ◽  
pp. 1607-1626 ◽  
Author(s):  
Amanda Frigola ◽  
Matthias Prange ◽  
Michael Schulz
Keyword(s):  
Boundary Conditions ◽  
General Circulation ◽  
Middle Miocene ◽  
Climate Models ◽  
Global Climate ◽  
Co2 Concentration ◽  
General Circulation Models ◽  
Global Climate Models ◽  
Climate System Model ◽  
Climate Transition

Abstract. The Middle Miocene Climate Transition was characterized by major Antarctic ice sheet expansion and global cooling during the interval ∼ 15–13 Ma. Here we present two sets of boundary conditions for global general circulation models characterizing the periods before (Middle Miocene Climatic Optimum; MMCO) and after (Middle Miocene Glaciation; MMG) the transition. These boundary conditions include Middle Miocene global topography, bathymetry, and vegetation. Additionally, Antarctic ice volume and geometry, sea level, and atmospheric CO2 concentration estimates for the MMCO and the MMG are reviewed. The MMCO and MMG boundary conditions have been successfully applied to the Community Climate System Model version 3 (CCSM3) to provide evidence of their suitability for global climate modeling. The boundary-condition files are available for use as input in a wide variety of global climate models and constitute a valuable tool for modeling studies with a focus on the Middle Miocene.

Sign in / Sign up

Export Citation Format

Share Document