Geology Today最新文献

Ammonites were molluscs, now extinct, that abounded in Mesozoic seas. Their external shells are almost always the only parts of them that are preserved, and their soft-part anatomy and lifestyles remain largely unknown. The shells, however, can be preserved in various ways that shed light on the animals as living organisms, including their variation and evolution, possible colour patterning and the creatures that preyed upon them.

The biggest UK railway construction site since the nineteenth century has exposed a near-complete time slice through the entire Jurassic succession of central England. This is yielding a wealth of stratigraphical, palaeobiological and palaeoenvironmental data that is otherwise generally poorly exposed at the present day. Construction of the HS2 (High Speed 2) railway scheme is generating important exposures of these strata, affording significant geological recording, research and educational opportunities.

The Lower Jurassic Down Cliff Sand Member of the Dorset coast, southern England, is a rich source of marine invertebrate fossils. Among these are echinoderms and less common arthropods. Despite having multi-component skeletons that are prone to disarticulation, remains of some of these are remarkably complete. This article examines the circumstances that could have led to their death, burial and intact preservation.

The city of Oxford, in south-central England, is partly surrounded by hills on which coral-rich limestones crop out. The coral developments constitute small reefs and formed during a widely documented Late Jurassic (mid-Oxfordian) warming episode, near the northern limit of reef growth at that time. Given its ready availability, the coral rock and associated detrital limestone were dug as building stone for 900 years or more and used extensively within Oxford until the beginning of the twentieth century. William Joscelyn Arkell (1904–1958) was a leading twentieth century expert on Jurassic geology and had wide-ranging interests in these strata. In particular, his observations on Oxfordian reef palaeoecology, climatic significance and structural context have provided the foundations of our modern understanding of these fascinating rocks, which are poorly exposed at the present day.

Can a beachcomber be a geologist in the absence of in situ rock exposures? I say yes, particularly for those of us with a fondness for Aktuo Paläontologie, the interpretation of modern shell remains as if they are fossils. Modern dead shells can provide a wealth of thought-provoking information, confirming that the present is, indeed, the key to the past.

Rapid atmospheric warming, especially at high altitude, leads to alpine mountain landscapes becoming more vulnerable to mass movements and consequently unstable. For example, decay of mountain permafrost contributes to rockfalls, landslides and debris flows; glaciers are retreating and losing mass at alarming rates, exposing unstable slopes that are more likely to fail; and meltwater, which collects in a growing number of glacial lakes, can pose an outburst flood hazard, putting communities and infrastructure downstream at risk of damage. Occurring now with increasing frequency, these natural phenomena often combine to create complex multi-hazard cascades that are more powerful and have a greater reach down-valley than a singular isolated event. Combined with increasing population and infrastructure and economic activity in high mountains, there is therefore increased vulnerability of society to natural hazards in high alpine mountains, as has been experienced in the Swiss Alps in 2025, with the collapse of the Birch Glacier and the destruction of the alpine village of Blatten. Here, we review the physical processes of this recent event, their impact on environment, people and economy, and consider what can be learned from them.

The Thistle landslide was a slow-moving mass of debris that, during 1983, created a dam within a major valley in Utah, USA. It proved to be the most expensive landslide in American history, requiring huge and rapid engineering works to stabilize the debris dam, build a new railway and road and drain the lake; though not before the small town of Thistle was drowned and destroyed.

Long-term preservation of landforms produces a geological record that can be used to unravel past Earth surface processes in space and time. Identification and analysis of landforms has been revolutionized by the availability of high-resolution (metre-scale) topographic survey data covering extensive areas, using Light Detection and Ranging (LiDAR). Airborne LiDAR has been in widespread use for over two decades; but due to increasing availability of data, some regions are only just beginning to be ‘explored’ in this way. In this article, we showcase high-resolution topography derived from airborne LiDAR survey data across South Island, New Zealand. We evidence a variety of tectonic, glacial, fluvial, hillslope and other landforms hitherto undetected within mountainous areas and beneath forests. We discuss how the characteristics of shape, size, position and association can differentiate landforms from one another, and how combinations of landforms enable landsystems to be identified that are diagnostic of past environmental conditions.