Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

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Towards the standardization of sequence stratigraphy

The new tectonic map of the Alps is based on the combination of purely structural data with criteria regarding paleogeographical affiliation and/or tectono-metamorphic evolution. The orogenic evolution of the Alps is discussed using a combination of maps and paleogeographical reconstructions. It is proposed that the Alps are the product of two orogenies, a Cretaceous followed by a Tertiary one. While the former is related to the closure of an embayment of the Meliata ocean into Apulia, the latter is due to the closure of the Alpine Tethys between Apulia and Europe. The along-strike changes in the overall architecture, as for example revealed by geophysical-geological transects, are by far more substantial than hitherto believed. It appears that the Alps are still far from being over-investigated, as is demonstrated by many surprising recent findings based on field geology, laboratory results and geophysical methods of deep sounding.

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Tectonic map and overall architecture of the Alpine orogen

Successful petroleum exploration relies on detailed analysis of the petroleum system in a given area. Identification of potential source rocks, their maturity and kinetic parameters, and their regional distribution are best accomplished by rapid screening of rock samples (cores and/or cuttings) using the Rock-Eval apparatus. The technique has been routinely used for about fifteen years and has become a standard tool for hydrocarbon exploration. This paper describes how the new functions of the latest version of Rock-Eval (Rock-Eval 6) have expanded applications of the method in petroleum geoscience. Examples of new applications are illustrated for source rock characterization, reservoir geochemistry, and environmental studies, including quantification.

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Rock-Eval 6 Applications in Hydrocarbon Exploration, Production, and Soil Contamination Studies

/pdf/reconciling-plate-tectonic-reconstructions-of-alpine-tethys-1do3i5vm2t.pdf

Reconciling plate-tectonic reconstructions of Alpine Tethys with the geological–geophysical record of spreading and subduction in the Alps

Evolution of early planktic foraminifers

The middle Cretaceous carbonate deposits in the Middle East are among the most productive oil-bearing stratigraphic intervals in the world, containing numerous giant fields in, for instance, the United Arab Emirates (Mauddud and Mishrif formations), Iran (Sarvak Formation), and Oman (Natih Formation). One of the main reasons for this concentration of hydrocarbons is a geological factor: the coexistence of both reservoir facies and source rocks in the same depositional sequences due to the repeated creation of organic-rich intrashelf basins. This is demonstrated in a high-resolution sequence stratigraphic study of the Natih Formation in Oman, which shows distinct and predictive patterns in the distribution and geometries of reservoir, source rock, and seal facies. The sequence stratigraphic model presented here may serve as a reference for time-equivalent deposits in the Middle East. The sedimentological analysis showed that the Natih Formation was formed by the alternation of two types of depositional systems: (1) a flat-bedded, mixed carbonate-clay ramp, dominated by benthic foraminifera, and (2) a carbonate-dominated ramp bordering an intrashelf basin, with abundant rudists in the mid-ramp environment and organic-rich basinal facies. Three fully developed third-order sequences are distinguished, showing a similar evolution of the depositional system, with a mixed carbonate-clay ramp system at the base, followed by a carbonate-dominated ramp system in the upper part. Variations occur on this pattern, however, depending on the relative influence of eustasy, environmental factors, and tectonism. The late Albiannearly Cenomanian sequence I shows an evolution from a mixed, flat ramp to a carbonate-dominated ramp and organic-rich intrashelf (Begin page 22) basin, and sedimentation is predominantly controlled by eustatic sea level. In the middle Cenomanian sequence II, the evolution from a mixed ramp to a carbonate ramp is also observed, but no intrashelf basin topography was developed in the studied area. This may be due to the high influx of clay that influenced the environment in this sequence, inhibiting the carbonate production, probably in combination with the lack of sufficient creation of accommodation space. The late Cenomaniannearly Turonian transgressive part of sequence III shows a similar evolution to that observed in sequence I, with the development of an organic-rich intrashelf basin. During highstand, however, a tectonically controlled sedimentation pattern is observed, with the development of forced regressive wedges (due to the flexural bulge of the foreland basin). Intrashelf basin formation occurred twice in the transgressive part of the third-order depositional sequences of the Natih Formation. Our study shows that this is mainly the result of differential sedimentation rates, that is, the dynamics of the carbonate sedimentary system itself in response to (rapid) rises in relative sea level, probably of eustatic origin. Tectonism was only a minor factor in the creation of the basin topography, possibly through the creation of small initial relief. The accumulation of the organic matter is not only a result of the creation of a sufficiently deep-water column to guarantee dysaerobic conditions for its preservation. The late Albian and late Cenomaniannearly Turonian were also periods of generally favorable conditions worldwide for high organic matter productivity. The time lines and stratigraphic architecture of the third-order sequences presented here have an application potential at the scale of the Arabian plate. The general sedimentation pattern is predicted by our model, but modifications due to different local conditions are likely to occur.

Stratigraphic organization of carbonate ramps and organic-rich intrashelf basins: Natih Formation (middle Cretaceous) of northern Oman

A remarkable exposure of Miocene marine molasse in western Switzerland records the evolution of a tidal sandwave over a period of approximately 2 1/2 months. The sandwave is composed of tidal ‘bundles’ in which a sandwave reactivation stage and full vortex stage can be recognized for the dominant flow (ebb tide) and a rippled flood apron overlain by high water drape for the reversed flow. Bundle thicknesses vary systematically through neap–spring cycles, with a periodicity of 27 demonstrating the semi-diurnal lunar control of sedimentation. Waves were an additional component, especially when superimposed on flood tides, producing near-symmetrical combined-flow ripple marks in the flood apron.



Tidal current velocities are estimated using critical shear velocities for entrainment, the ripple-dune transition and the dune-plane bed transition. Using appropriate estimates of roughness lengths and a logarithmic velocity law, maximum tidal speeds at 1 m above the bed were approximately 0·6 m sec−1 for ebbs and up to 0·5 m sec−1 for floods. The enhancement by waves of bed shear stress (τwc/τ of approximately 2 for 1 m high waves) under flood currents implies flood tidal velocities closer to 0·2–0·3 m sec−1.



Peak instantaneous bedload sediment transport rates using a modified Bagnold equation are nearly 5 times greater under ebb tides than floods. The average net sediment transport rate at springs (0·04 kg m−1 sec−1) is over 10 times greater than at neaps (0·002 kg m−1 sec−1). Comparison with transport rates in modern tidal environments suggests that the marine molasse of Switzerland was deposited under spatially confined and relatively swift tidal flows not dissimilar to those of the present Dutch tidal estuaries.

Peter Homewood

Papers

Evolution of early planktic foraminifers

Stratigraphic organization of carbonate ramps and organic-rich intrashelf basins: Natih Formation (middle Cretaceous) of northern Oman

Evolution and mechanics of a Miocene tidal sandwave

Foreland Basins: An Introduction

Dynamics of the Molasse Basin of Western Switzerland