Alastair Ruffell

Bio: Alastair Ruffell is an academic researcher from Queen's University Belfast. The author has contributed to research in topics: Cretaceous & Aptian. The author has an hindex of 34, co-authored 151 publications receiving 3610 citations. Previous affiliations of Alastair Ruffell include Queen's University & Royal School of Mines.

Climatic and biotic change in the late Triassic

Abstract: Generally arid conditions that pervaded much of Europe and North America during the late Triassic were interrupted by a wet monsoonal climatic phase during Middle and Late Carnian times. Extensive fluviatile sandstones deposited at this time throughout the region, occur within a thick sequence of playa-lake mudstones. The sandstones occasionally contain kaolinite, suggesting a humid climate. An extreme δ 13 C depletion in a shallow marine sequence of this age in Israel has been interpreted as evidence for an influx of freshwater. A widespread change from carbonates to clastics in marine sequences at this time may also be climate-related. Water-course cave systems in limestone areas exposed during the late Triassic indicate high levels of runoff during the Middle and Late Carnian. The marine invertebrate fauna shows a significant turnover at the end of the Early Carnian. The terrestrial fauna and flora were relatively unaffected at this time but subsequently diversified prior to a major biotic turnover at the Carnian-Norian boundary. These periods of biotic change appear to be synchronous with the onset and cessation of a Carnian humid phase. The change to a monsoonal climate during this interval has been documented over more than 90° of longitude between 5° and 50° north of the Triassic equator. It may have been caused by rising atmospheric CO 2 levels due to volcanism associated with the incipient dispersal of Pangaea.

Purbeck–Wealden (early Cretaceous) climates

Abstract: A multidisciplinary colligation including new data and analysis of the evidence for the climates of southern Britain during c. 140 Ma. to c. 120 Ma BP (Berriasian-Barremian — ? earliest Aptian). The climate was at first hot, semi-arid and ‘Mediterranean’ (rather than ‘monsoonal’) in type, probably with seasonally opposed winds (E/W). An irregular long-term trend of increasing rainfall in the moister seasons is evident. This was probably associated with establishment of predominant westerlies during the Jurassic-Cretaceous transition and slightly lower average annual temperatures thereafter until Barremian times. Causes proposed are frequent changes in the regional climatic system due to technically induced adjustments of relief under the special conditions of the semi-enclosed Purbeck–Wealden archipelago and increasing proximity of the widening Protoatlantic sea.

A burning story: The role of fire in the history of life

Abstract: Ecologists, biogeographers, and paleobotanists have long thought that climate and soils controlled the distribution of ecosystems, with the role of fire getting only limited appreciation. Here we review evidence from different disciplines demonstrating that wildfire appeared concomitant with the origin of terrestrial plants and played an important role throughout the history of life. The importance of fire has waxed and waned in association with changes in climate and paleoatmospheric conditions. Well before the emergence of humans on Earth, fire played a key role in the origins of plant adaptations as well as in the distribution of ecosystems. Humans initiated a new stage in ecosystem fire, using it to make the Earth more suited to their lifestyle. However, as human populations have expanded their use of fire, their actions have come to dominate some ecosystems and change natural processes in ways that threaten the sustainability of some landscapes.