116,738 research outputs found
Preservation of Data for Earth System Science- Towards a Content Standard
Various remote sensing agencies of the world have created a data rich environment for research and applications over the last three decades. Especially over the last decade, the volume and variety of data useful for Earth system science have increased quite rapidly. One of the key purposes of collecting these data and generating useful digital products containing derived geophysical parameters is to study the long-term trends in the Earth s behavior. Long-term observational data and derived products are essential for validating results from models that predict the future behavior of the Earth system. Given the significant resources expended in gathering the observational data and developing the derived products, it is important to preserve them for the benefit of future generations of users. Preservation involves maintaining the bits with no loss (or loss within scientifically acceptable bounds) as they move across systems as well as over time, ensuring readability over time, and providing for long-term understandability and repeatability of previously obtained results. In order to ensure long-term understandability and repeatability, it is necessary to identify all items of content that must be preserved and plan for such preservation. This paper discusses the need for a standard enumerating and describing such content items and reports on the progress made by NASA and the Federation of Earth Science Information Partners (ESIP Federation) in the U.S. towards such a standard
Aspects of the taphonomy of the Cambrian Explosion in North Greenland
This thesis describes and elucidates the taphonomic pathways responsible for the exceptional preservation of some of the most common elements of the Sirius Passet Lagerstätte (early Cambrian), North Greenland. Investigative techniques including cathodoluminescence, are tested first on silicified molluscs from the Oligocene of Antigua, associated with a volcanic source; described in chapter 2. By describing the depositional environment of the Sirius Passet biota in detail and using a combination of analytical techniques such as SEM, EDAX, SEM-CL and elemental mapping two published papers address a number of the key research questions surrounding the unique taphonomic pathways in the Sirius Passet biota and their broader significance in understanding Cambrian ecosystems. The papers are included in the form of chapters 3 and 4 and the published versions included in the appendices. A unique, mat-dominated, tissue specific taphonomic pathway is proposed, more akin to the Proterozoic than the typical Burgess Shale Type (BST) preservation seen elsewhere in the Cambrian. This together with mouldic preservation indicates a range of taphonomic styles concomitant with the range of new biotas at the dawn of the Cambrian Explosion
3D modelling of geological and anthropogenic deposits at the World Heritage Site of Bryggen in Bergen, Norway
The landscape of many historic cities and the character of their shallow subsurface environments are
defined by a legacy of interaction between anthropogenic and geological processes. Anthropogenic
deposits and excavations result from processes ranging from archaeological activities to modern urban
development. Hence, in heritage cities, any geological investigation should acknowledge the role of past
and ongoing human activities, while any archaeological investigation should be conducted with geological
processes in mind. In this paper it is shown that 3D geological and anthropogenic models at different scales
can provide a holistic system for the management of the subsurface. It provides a framework for the
integration of other spatial and processmodels to help assess the preservationpotential for buried heritage.
Such an integrated framework model is thus contributing to a decision support system for sustainable
urban (re)development and regeneration in cities, while preserving cultural heritage. A collaborative
approach is proposed to enhance research and implementation of combined geological and archaeological
modelling for sustainable land use planning and heritage preservation, using York and Bryggen as prime
examples. This paper presents the status of 3D framework modelling at Bryggen in Norway as an example
Understanding the Middle Miocene Climatic Optimum: Evaluation of Deuterium Values (δD) Related to Precipitation and Temperature
The Middle Miocene Climate Optimum was a unique warming period in the Earth’s geologic history, when a high global mean annual temperature was accompanied by a relatively low global CO2 concentration. Hydrogen isotopic signals (specifically molecular δD, the ratio of deuterium to hydrogen) from lipids of fossils and sediments offer intrinsic insights into precipitation of ancient climates. Using samples collected from known Middle Miocene deposits, we measured δD of n-alkanes extracted from well-preserved plant and sediment samples from varying latitudes across the Northern Hemisphere, and then analyzed the data through a zonally averaged precipitation and evaporation climate model. The reduced latitudinal temperature gradient with warm polar regions during the Middle Miocene was also contrarily coupled with a small variance in latitudinal meteoric water composition and precipitation. With our latitudinally variant sample locations (ranging from 24°N in Xianfeng, China, to 74°N in Banks Island, Canada), we developed a one-dimensional model in which we assessed evaporation and precipitation gradients throughout the Northern Hemisphere. Ultimately, we used the latitudinal distribution of δD to better constrain the atmospheric conditions during the Middle Miocene Climatic Optimum
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Astronomically paced changes in overturning circulation in the Western North Atlantic during the middle Eocene
North Atlantic Deep Water (NADW) currently redistributes heat and salt between Earth’s ocean basins, and plays a vital role in the ocean-atmosphere CO2 exchange. Despite its crucial role in today’s climate system, vigorous debate remains as to when deep-water formation in the North Atlantic started. Here, we present datasets from carbonate-rich middle Eocene sediments from the Newfoundland Ridge, revealing a unique archive of paleoceanographic change from the progressively cooling climate of the middle Eocene. Well-defined lithologic alternations between calcareous ooze and clay-rich intervals occur at the ∼41-kyr beat of axial obliquity. Hence, we identify obliquity as the driver of middle Eocene (43.5–46 Ma) Northern Component Water (NCW, the predecessor of modern NADW) variability. High-resolution benthic foraminiferal δ18O and δ13C suggest that obliquity minima correspond to cold, nutrient-depleted, western North Atlantic deep waters. We thus link stronger NCW formation with obliquity minima. In contrast, during obliquity maxima, Deep Western Boundary Currents were weaker and warmer, while abyssal nutrients were more abundant. These aspects reflect a more sluggish NCW formation. This obliquity-paced paleoceanographic regime is in excellent agreement with results from an Earth system model, in which obliquity minima configurations enhance NCW formation
Building a Disciplinary, World-Wide Data Infrastructure
Sharing scientific data, with the objective of making it fully discoverable,
accessible, assessable, intelligible, usable, and interoperable, requires work
at the disciplinary level to define in particular how the data should be
formatted and described. Each discipline has its own organization and history
as a starting point, and this paper explores the way a range of disciplines,
namely materials science, crystallography, astronomy, earth sciences,
humanities and linguistics get organized at the international level to tackle
this question. In each case, the disciplinary culture with respect to data
sharing, science drivers, organization and lessons learnt are briefly
described, as well as the elements of the specific data infrastructure which
are or could be shared with others. Commonalities and differences are assessed.
Common key elements for success are identified: data sharing should be science
driven; defining the disciplinary part of the interdisciplinary standards is
mandatory but challenging; sharing of applications should accompany data
sharing. Incentives such as journal and funding agency requirements are also
similar. For all, it also appears that social aspects are more challenging than
technological ones. Governance is more diverse, and linked to the discipline
organization. CODATA, the RDA and the WDS can facilitate the establishment of
disciplinary interoperability frameworks. Being problem-driven is also a key
factor of success for building bridges to enable interdisciplinary research.Comment: Proceedings of the session "Building a disciplinary, world-wide data
infrastructure" of SciDataCon 2016, held in Denver, CO, USA, 12-14 September
2016, to be published in ICSU CODATA Data Science Journal in 201
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