Malcolm B. Hart

Bio: Malcolm B. Hart is an academic researcher from University of Plymouth. The author has contributed to research in topics: Foraminifera & Cretaceous. The author has an hindex of 35, co-authored 184 publications receiving 4373 citations. Previous affiliations of Malcolm B. Hart include British Museum & University of Sheffield.

Biotic Recovery from Mass Extinction Events

Abstract: Containing papers by leading authorities on several of the major extinction events of the geological record, the volume brings together new data on a wide range of floral and faunal groups. Several of the papers describe the recovery and recolonization processes following the extinction events while others discuss the problems of'survivor taxa', "disaster taxa' and "progenitor species'. The examples chosen come from geological successions in North America, South America, Europe, Asia and the Indian Subcontinent.

A water depth model for the evolution of the planktonic Foraminiferida

Abstract: Recent papers on the evolution of the planktonic Foraminiferida have stressed the importance of repeated patterns1,2 in the Neogene and Palaeogene, as well as in the Cretaceous1–4. Most authors have recognized the importance of gross morphological characters (the biocharacters of Steineck and Fleischer2) and used them to illustrate the evolution of the superfamily Glo-bigerinacea, as well as a prime tool in classification. Cifelli1 and Frerichs4 relate such patterns of evolution to the available palaeotemperature data5, and while temperature is clearly important I shall show that it is not the complete story. Here the evolution of the planktonic Foraminiferida is reconsidered in the light of recent advances in the understanding of distributional controls of the modern fauna. I suggest that well-known ‘iterative’ trends indicate successive attempts at colonizing deeper levels in the water column.

Cretaceous foraminiferal morphogroup distribution patterns, palaeocommunities and trophic structures: a case study from the Sergipe Basin, Brazil

Abstract: Foraminiferal studies have been used in palaeo-environmental reconstructions of the marine Cretaceous succession (upper Aptian to Maastrichtian) of the Sergipe Basin, in northeastern Brazil. The foraminiferal assemblages show broadly three types of response to changes in environment: (1) variations in morphotypes of the taxa present; (2) changes in specific and generic diversity; and (3) changes in relative abundance.Twelve palaeocommunities, characterised by the relative dominance of the major foraminiferal groups, can be recognised in the succession. Their palaeoenvironmental distribution is proposed as a model with reference to the Sergipe Cretaceous sequence.An intimate relationship is inferred among foraminiferal association distribution patterns, trophic structures (community feeding strategy, dwelling habits, substrate niche patterns) and water-mass conditions (depth-related in part). It is suggested that the distribution patterns may be a direct response of the functional adaptive morphology of the foraminiferal tests to individual characteristics of behavioural structure (preferential dwelling microhabitat and trophic strategy versus environment). The approach is a simple, yet very powerful tool, for the interpretation of foraminiferal palaeocommunities and palaeoceanographic research. It may also permit interpretation of palaeocommunity strategies in terms of adaptation rate and selection response (i.e. “r-selection” versus “k-selection”) to variable environmental conditions.

The Theory of Island Biogeography

Abstract: 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

Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores

Abstract: Matrix-related pore networks in mudrocks are composed of nanometer- to micrometer-size pores. In shale-gas systems, these pores, along with natural fractures, form the flow-path (permeability) network that allows flow of gas from the mudrock to induced fractures during production. A pore classification consisting of three major matrix-related pore types is presented that can be used to quantify matrix-related pores and relate them to pore networks. Two pore types are associated with the mineral matrix; the third pore type is associated with organic matter (OM). Fracture pores are not controlled by individual matrix particles and are not part of this classification. Pores associated with mineral particles can be subdivided into interparticle (interP) pores that are found between particles and crystals and intraparticle (intraP) pores that are located within particles. Organic-matter pores are intraP pores located within OM. Interparticle mineral pores have a higher probability of being part of an effective pore network than intraP mineral pores because they are more likely to be interconnected. Although they are intraP, OM pores are also likely to be part of an interconnected network because of the interconnectivity of OM particles. In unlithifed near-surface muds, pores consist of interP and intraP pores, and as the muds are buried, they compact and lithify. During the compaction process, a large number of interP and intraP pores are destroyed, especially in ductile grain-rich muds. Compaction can decrease the pore volume up to 88% by several kilometers of burial. At the onset of hydrocarbon thermal maturation, OM pores are created in kerogen. At depth, dissolution of chemically unstable particles can create additional moldic intraP pores.

A Mesozoic time scale

Abstract: We present an integrated geomagnetic polarity and stratigraphic time scale for the Triassic, Jurassic, and Cretaceous periods of the Mesozoic Era, with age estimates and uncertainty limits for stage boundaries. The time scale uses a suite of 324 radiomenc dates, including high-resolution 40 Ar/ 39 Ar age estimates. This framework involves the observed ties between (1) radiometric dates, biozones, and stage boundaries, and (2) between biozones and magnetic reversals on the seafloor and in sediments. Interpolation techniques include maximum likelihood estimation, smoothing cubic spline fitting, and magnetochronology