1. Sediments and Methods of Their Study 2. Erosional Processes 2.1. Weathering 2.2. Transport 3. Depositional Processes and Sediment Types 3.1. Features of Detrital Sediments 3.2. Bedforms and Sedimentary Structures 3.3. Trace Fossils 3.4. Gravity Flows 3.5. Classification of Detrital Sediments 3.6. Origin of Chemogenic and Biogenic Sediments 3.7. Classification of Carbonate Rocks 4. Depositional Environments 4.1. Arid Continental Environments 4.2. Humid Continental Environments 4.3. Glacial Sediments 4.4. Shallow Marine Sediments 4.5. Deep Marine Sediments 5. Sedimentary Basins and Their Types and Preservation 6. The Facies Concept and Multi-Story Sedimentary Packages 7. Post-Depositional Processes 8. Sediment Utilization Glossary Bibliography Biographical Sketch

堆積岩 = Sedimentary rocks

We consider growing spheres seeded by random injection in time and space. Growth stops when two spheres meet leading eventually to a jammed state. We study the statistics of growth limited by packing theoretically in d dimensions and via simulation in d=2, 3, and 4. We show how a broad class of such models exhibit distributions of sphere radii with a universal exponent. We construct a scaling theory that relates the fractal structure of these models to the decay of their pore space, a theory that we confirm via numerical simulations. The scaling theory also predicts an upper bound for the universal exponent and is in exact agreement with numerical results for d=4.

Packing-Limited Growth

Neutral Community Ecology

There are a few common species and many rare species in a biological community or a multi-species collection in given space and time. This hollow distribution curve is called species abundance distribution (SAD). Few studies have examined the patterns and dynamics of SADs during the succession of forest communities by model selection. This study explored whether the communities in different successional stages followed different SAD models and whether there existed a best SAD model to reveal their intrinsic quantitative features of structure and dynamics in succession. The abundance (the number of individuals) of each vascular plant was surveyed by quadrat sampling method from the tree, shrub and herb layers in two typical communities (i.e., the evergreen needle- and broad-leaved mixed forest and the monsoon evergreen broad-leaved forest) in southern subtropical Dinghushan Biosphere Reserve, South China. The sites of two forest communities in different successional stages are both 1 ha in area. We collected seven widely representative SAD models with obviously different function forms and transformed them into the same octave (log2) scale. These models are simultaneously confronted with eight datasets from four layers of two communities, and their goodness-of-fits to the data were evaluated by the chi-squared test, the adjusted coefficient of determination and the information criteria. The results indicated that: (1) the logCauchy model followed all the datasets and was the best among seven models; (2) the fitness of each model to the data was not directly related to the successional stage of forest community; (3) according to the SAD curves predicted by the best model (i.e., the logCauchy), the proportion of rare species decreased but that of common ones increased in the upper layers with succession, while the reverse was true in the lower layers; and (4) the difference of the SADs increased between the upper and the lower layers with succession. We concluded that the logCauchy model had the widest applicability in describing the SADs, and could best mirror the SAD patterns and dynamics of communities and their different layers in the succession of forests. The logCauchy-modeled SADs can quantitatively guide the construction of ecological forests and the restoration of degraded vegetation.

/pdf/examining-the-patterns-and-dynamics-of-species-abundance-zy97h97e7q.pdf

Examining the patterns and dynamics of species abundance distributions in succession of forest communities by model selection.

The apparent constancy of the near linear relationship between logarithm of a specie’s abundance in a community and their rank order led to a brief review of existing species abundance distribution (SAD) models; a proposal of three further classes of analogue models; and an evaluation of a meta data set of empirical vegetation composition data. A new class of models is proposed considered particle packing of circles (2D) or spheres (3D) as representing individuals of species which under different scenarios of arrival, growth, displacement and mortality determine community maximum packing and SAD. Besides the existing random models treating each species as an entity, two further classes are added which considered dismantling rather than assembly models, or retaining identity of taxa species through successive stages of assembly or dismantling models. In each of the models, the resulting form of the SAD was dependent on which metric of an individual (density, area, volume etc) was used as a measure of abundance. A comparison was made between the resulting 576 different models and 432 sets of 10 species and 110 sets of 5 species empirical observations. There was a wide variation in species proportions and a lack of clustering around a particular model. In those comparisons, the particle packing models of individuals were as good as the random models treating species as an entity and did offer a functional explanation of the formation of the SAD. In most models and empirical data the species ranking is done retrospectively so there will always be a high negative correlation between abundance and rank implying a need for a revaluation of the ecological significance of the relationship.

/pdf/analogue-particle-and-random-packing-models-of-ecological-4ejm0a8m1q.pdf

Analogue Particle and Random Packing Models of Ecological Community Formation

A comparison was made between analysis methods of archived monitoring data for extrapolating quantitative values or trends from additional partial measurements. These were done from both the ‘species from environment and management’ or ‘environment and management from species’ predictions. The sample data used was from two 19 year annually monitored grazing trials in a tussock grassland environment under 90 different controlled inputs, but treated as if from a random ecological survey. Quantitative estimation of trends from such a reference data set was best by a direct data search for closest matching observation, followed by response surface regression, simple multiple regression, multiple imputation, transformation regression, and least from principal component analysis.

/pdf/prediction-from-archived-vegetation-and-environmental-46c0ozxu0u.pdf

Prediction From Archived Vegetation and Environmental Monitoring Data

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Analogue Particle and Random Packing Models of Ecological Community Formation

Prediction From Archived Vegetation and Environmental Monitoring Data