Continental interior parabolic dunes as a potential proxy for past climates

The past was a world of giants, with abundant whales in the sea and large animals roaming the land. However, that world came to an end following massive late-Quaternary megafauna extinctions on land and widespread population reductions in great whale populations over the past few centuries. These losses are likely to have had important consequences for broad-scale nutrient cycling, because recent literature suggests that large animals disproportionately drive nutrient movement. We estimate that the capacity of animals to move nutrients away from concentration patches has decreased to about 8% of the preextinction value on land and about 5% of historic values in oceans. For phosphorus (P), a key nutrient, upward movement in the ocean by marine mammals is about 23% of its former capacity (previously about 340 million kg of P per year). Movements by seabirds and anadromous fish provide important transfer of nutrients from the sea to land, totalling ∼150 million kg of P per year globally in the past, a transfer that has declined to less than 4% of this value as a result of the decimation of seabird colonies and anadromous fish populations. We propose that in the past, marine mammals, seabirds, anadromous fish, and terrestrial animals likely formed an interlinked system recycling nutrients from the ocean depths to the continental interiors, with marine mammals moving nutrients from the deep sea to surface waters, seabirds and anadromous fish moving nutrients from the ocean to land, and large animals moving nutrients away from hotspots into the continental interior.

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HYDROLOGICAL AND BIOGEOCHEMICAL CYCLING DURING RAPID WARMING EVENTS IN THE CONTINENTAL INTERIOR UNITED STATES

10.3997/2214-4609.202134093 ◽

2021 ◽

Author(s):

A. Elson ◽

M. Rohrssen ◽

J. Marshall ◽

G. Inglis ◽

J. Whiteside

Keyword(s):

United States ◽

Biogeochemical Cycling ◽

Continental Interior

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Temperature seasonality in the North American continental interior during the early Eocene climatic optimum

10.5194/cp-2018-28 ◽

2018 ◽

Cited By ~ 1

Author(s):

Ethan G. Hyland ◽

Katharine W. Huntington ◽

Nathan D. Sheldon ◽

Tammo Reichgelt

Keyword(s):

Climate Model ◽

Regional Climate ◽

Early Eocene ◽

Early Eocene Climatic Optimum ◽

The North ◽

Annual Range ◽

Climatic Optimum ◽

Temperature Records ◽

Model Ensembles ◽

Continental Interior

Abstract. Paleogene greenhouse climate equability has long been a paradox in paleoclimate research. However, recent developments in proxy and modeling methods have suggested that strong seasonality may be a feature of at least some greenhouse periods. Here we present the first multi-proxy record of seasonal temperatures during the Paleogene from paleofloras, paleosol geochemistry, and carbonate clumped isotope thermometry in the Green River Basin (Wyoming, USA). These combined temperature records allow for the reconstruction of past seasonality in the continental interior, which shows that temperatures were warmer in all seasons during the peak early Eocene climatic optimum and that the mean annual range of temperature was high, similar to the modern value (~ 26 °C). Proxy data and downscaled Eocene regional climate model results suggest amplified seasonality during greenhouse events. Increased seasonality reconstructed for the early Eocene is similar in scope to the higher seasonal range predicted by downscaled climate model ensembles for future high-CO2 emissions scenarios. Overall, these data and model comparisons have substantial implications for understanding greenhouse climates in general, and may be important for predicting future seasonal climate regimes and their impacts in continental regions.

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Impacts of Local Soil Moisture Anomalies on the Atmospheric Circulation and on Remote Surface Meteorological Fields during Boreal Summer: A Comprehensive Analysis over North America

Journal of Climate ◽

10.1175/jcli-d-16-0192.1 ◽

2016 ◽

Vol 29 (20) ◽

pp. 7345-7364 ◽

Cited By ~ 37

Author(s):

Randal D. Koster ◽

Yehui Chang ◽

Hailan Wang ◽

Siegfried D. Schubert

Keyword(s):

Soil Moisture ◽

North America ◽

Atmospheric Circulation ◽

General Circulation ◽

Boreal Summer ◽

Near Surface ◽

Local Soil ◽

Lower Mississippi River ◽

Continental Interior ◽

The U.S

Abstract A series of stationary wave model (SWM) experiments are performed in which the boreal summer atmosphere is forced, over a number of locations in the continental United States, with an idealized diabatic heating anomaly that mimics the atmospheric heating associated with a dry land surface. For localized heating within a large portion of the continental interior, regardless of the specific location of this heating, the spatial pattern of the forced atmospheric circulation anomaly (in terms of 250-hPa eddy streamfunction) is largely the same: a high anomaly forms over west-central North America and a low anomaly forms to the east. In supplemental atmospheric general circulation model (AGCM) experiments, similar results are found; imposing soil moisture dryness in the AGCM in different locations within the U.S. interior tends to produce the aforementioned pattern, along with an associated near-surface warming and precipitation deficit in the center of the continent. The SWM-based and AGCM-based patterns generally agree with composites generated using reanalysis and precipitation gauge data. The AGCM experiments also suggest that dry anomalies imposed in the lower Mississippi River valley have remote surface impacts of particularly large spatial extent, and a region along the eastern half of the U.S.–Canadian border is particularly sensitive to dry anomalies in a number of remote areas. Overall, the SWM and AGCM experiments support the idea of a positive feedback loop operating over the continent: dry surface conditions in many interior locations lead to changes in atmospheric circulation that act to enhance further the overall dryness of the continental interior.

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The Mesoscale Response to Global Warming over the Pacific Northwest Evaluated Using a Regional Climate Model Ensemble

Journal of Climate ◽

10.1175/jcli-d-21-0061.1 ◽

2021 ◽

pp. 1-56

Keyword(s):

Global Warming ◽

Pacific Northwest ◽

Climate Models ◽

Climate Model ◽

Regional Climate ◽

Wrf Model ◽

Regional Climate Models ◽

Winter Precipitation ◽

Historical Period ◽

Continental Interior

This paper describes the downscaling of an ensemble of twelve GCMs using the WRF model at 12-km grid spacing over the period 1970-2099, examining the mesoscale impacts of global warming as well as the uncertainties in its mesoscale expression. The RCP 8.5 emissions scenario was used to drive both global and regional climate models. The regional climate modeling system reduced bias and improved realism for a historical period, in contrast to substantial errors for the GCM simulations driven by lack of resolution. The regional climate ensemble indicated several mesoscale responses to global warming that were not apparent in the global model simulations, such as enhanced continental interior warming during both winter and summer as well as increasing winter precipitation trends over the windward slopes of regional terrain, with declining trends to the lee of major barriers. During summer there is general drying, except to the east of the Cascades. April 1 snowpack declines are large over the lower to middle slopes of regional terrain, with small snowpack increases over the lower elevations of the interior. Snow-albedo feedbacks are very different between GCM and RCM projections, with the GCM’s producing large, unphysical areas of snowpack loss and enhanced warming. Daily average winds change little under global warming, but maximum easterly winds decline modestly, driven by a preferential sea level pressure decline over the continental interior. Although temperatures warm continuously over the domain after approximately 2010, with slight acceleration over time, occurrences of temperature extremes increase rapidly during the second half of the 21st century.

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Conclusion

India and the Silk Roads ◽

10.1093/oso/9780197581070.003.0010 ◽

2021 ◽

pp. 257-268

Author(s):

Jagjeet Lally

Keyword(s):

Twentieth Century ◽

Global History ◽

Multiple Forms ◽

The Third ◽

Merchant Networks ◽

Continental Interior ◽

The Way

The endurance of terrestrial forms of connectivity over the Eurasian continental interior lies at the heart of this book. By reviewing the life of such connections in the twentieth century, this chapter draws out this book’s four major interventions. The first concerns the value of examining long-term patterns of change and the virtue of thinking across such divides as Mughal and British, pre-colonial and colonial. The second relates to the way this book thinks about empires in novel ways, whether by taking a trans-imperial framework or by focussing on the ways non-political entities—such as merchant networks—persisted through periods of imperial flux and the rise and fall of empires. The third is the focus on space, particularly interior or inner-continental space, and its place within global history. The final contribution is to provide an impetus to scholars to think of the synchronicity of multiple forms of globalisation and their interrelation.

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Basement in the Continental Interior of the United States: ABSTRACT

AAPG Bulletin ◽

10.1306/bc743cbd-16be-11d7-8645000102c1865d ◽

1964 ◽

Vol 48 ◽

Cited By ~ 1

Author(s):

W. R. Muehlberger, R. E. Denison, E

Keyword(s):

United States ◽

The United States ◽

Continental Interior

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Fossil crocodilian distributions, Upper Cretaceous to present: implications for paleoclimate

The Paleontological Society Special Publications ◽

10.1017/s2475262200007589 ◽

1992 ◽

Vol 6 ◽

pp. 198-198

Author(s):

Paul Markwick

Keyword(s):

Late Cretaceous ◽

Middle Eocene ◽

Global Climate ◽

A Priori ◽

Tropical Regions ◽

Cooling Trend ◽

Geologic Record ◽

Continental Interior ◽

Different Levels ◽

Limited Scope

The present day distribution of crocodilians appears to be climatically controlled, at least in part, with the group restricted to tropical through sub-tropical regions. Studies have shown that although crocodiles may be able to withstand sub-zero temperatures they can do so for only limited periods. By analogy the presence of fossil crocodilians in the geologic record has been interpretated as indicating warmth. However previous studies have generally been of limited scope. This study uses global paleodistributions of the crocodilians to map gross global climate for the last 100 million years.A comprehensive database of published occurrences of fossil crocodilians from the late Cretaceous to the Present has been constructed. Taphonomic and collection biases have been addressed using ‘control groups', these are respectively the Testudines and the vertebrates in general. Problems of taxonomic inconsistency have been dealt with by ‘accepting’ a standard published taxonomic scheme (Carroll, 1988). Geographic and temporal uncertainties and imprecisions are coded on the database to facilitate sorting; this allows the analyses to be run at different levels of precision and provides an opportunity to understand the way biogeographic and hence paleoclimatic interpretations may be influenced by both the nature of the geologic record itself and by a priori decisions made by the worker. The database also includes lithologic, stratigraphic and environmental information on some 3300 localities and includes specimen information for the taxa entered (>14000 separate entries assembled from 1000 references).Preliminary analyses of paleolatitudinally reconstructed localities reveals the following trends: an overall equatorward movement of the poleward limit of the crocodiles from the late Cretaceous to the present; this is punctuated by an abrupt equatorward excursion of almost 10° during the Oligocene and another of similar magnitude at the end of the Miocene, with an apparent Miocene ‘recovery’ in between (this trend is shown most clearly by the families Alligatoridae and Crocodylidae). At the suborder level the Mesosuchians (excluding the Sebecidae) show a distinct equatorial shift from the Campanian through to the middle Eocene when they disappear; inclusion of the Sebecidae in the Mesosuchia gives rise to a sudden poleward expansion in the middle Eocene of some 20° paleolatitude. Map reconstructions, especially for North America, reveal an eastward shift of crocodilian localities as the Tertiary progresses, perhaps due in part to a taphonomic artifact, viz., the migration of the locus of sedimentation. With the late Miocene the crocodilians disappeared completely from the continental interior record, a transition which seems tied to increased aridity (as indicated by the development of caliches in many areas) and increased seasonality of temperature. This pattern is also seen in the southern ‘U.S.S.R’.The distributions of the Crocodylia through time therefore reflect and support established views concerning late Cretaceous through Tertiary climate with a general cooling trend from the late Cretaceous to the present punctuated by abrupt coolings in the Oligocene and around the Miocene-Pliocene boundary.

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Geochemistry of Middle Triassic gabbros from northern Liaoning, North China: origin and tectonic implications

Geological Magazine ◽

10.1017/s0016756808005530 ◽

2008 ◽

Vol 146 (4) ◽

pp. 540-551 ◽

Cited By ~ 19

Author(s):

XIAOHUI ZHANG ◽

HONGFU ZHANG ◽

MINGGUO ZHAI ◽

SIMON A. WILDE ◽

LIEWEN XIE

Keyword(s):

North China ◽

Orogenic Belt ◽

Shrimp Dating ◽

The North ◽

Magmatic Underplating ◽

Granitic Intrusions ◽

Ultramafic Cumulates ◽

Geochronological Dating ◽

T Values ◽

Continental Interior

AbstractThe Xiaofangshen mafic stock is a hornblende gabbroic body emplaced in the Faku dome of northern Liaoning within the continental interior of the North China–Mongolian plate. Zircon U–Pb SHRIMP dating yields an emplacement age of 241 ± 6 Ma. These gabbroic rocks exhibit strong enrichment in large ion lithophile elements (e.g. Th, U) and light REE, slightly negative Eu anomalies, and pronounced depletion in high field strength elements (e.g. Nb, Ta, Zr, Ti). They show a relatively narrow range of isotopic compositions with initial 87Sr/86Sr ratios of 0.7053 to 0.7055, ϵNd(t) values of +0.40 to +0.68 and zircon ϵHf(T) values from +5.0 to +7.4. These geochemical features suggest that they might have been derived from partial melting of a subduction-related metasomatized lithospheric mantle source, which is tectonically affiliated to the Xing-Meng orogenic belt. Combined with our previous geochronological dating on the predominantly granitic intrusions from the Faku dome, it is inferred that the northern Liaoning block has a tectonic affinity with the Phanerozoic accretionary orogenic belt. This revelation further leads to the proposition that the Chifeng–Kaiyuan fault likely represents the Mesozoic lithospheric boundary between the North China craton and the Xing-Meng orogenic belt in northern Liaoning. The Xiaofangshen gabbros, together with the Triassic mafic–ultramafic cumulates and granulite xenoliths and the Triassic alkaline intrusions within the continental interior of the newly amalgamated North China–Mongolian Plate, constitute an important post-orogenic to within-plate anorogenic magmatic province, in response to the continued magmatic underplating caused by lithospheric delamination and hot asthenosphere upwelling.

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