Geology Today最新文献

When a volcano erupts, it is often associated with destruction, particularly damage to infrastructure and loss of life. But these natural events also offer unexpected research opportunities, leading to serendipitous discoveries. This was the case for the volcanic events that made the headlines during 19 September to 25 December 2021, on the Canarian Island of La Palma. Rather than viewing the voluminous ash that erupted as a waste material needing to be removed as soon as possible, we saw the many possibilities that this remarkable material could offer science and engineering. Sustainability is a word that is commonly used in connection with geology these days. Here we present some possibilities of how the La Palma ash can be re-purposed for use on this planet but also help us to develop new ideas for the future living on the Moon.

The Vasquez Rocks of Agua Dulce and Santa Clarita, California, USA have become associated with other planets or dimensions since the 1960s, when the popular American television programme Star Trek used them as dramatic backdrops in three episodes, ‘Arena’, ‘The Alternative Factor’ and ‘Friday's Child’. Today they are a popular visitor attraction, but what is their geological background?

The Central Series of the Paleocene mafic to ultramafic Rum complex is the youngest of the three main cumulate series that make up the layered igneous complex of this famed Scottish island. The Central Series lies along the Long Loch Fault and provides insights into the feeder system to the Rum intrusion at an erosion level of about two kilometres below the former land surface. Much of the Central Series consists of a mélange of steep sided bodies of magmatic breccias that stretch along the Long Loch Fault (LLF) in a relatively narrow zone and is composed of blocks and clasts of all sizes derived largely from break-up of the former conduit walls. Repeated movements of the LLF are thought to have been responsible for opening and closing of the magma conduit, resulting in repeated replenishment events, each of which gave rise to new cumulate formation within the Central Series and the bordering Eastern and Western Layered Series, which crystallized under relatively tranquil conditions. The Central Series probably acted as the feeder zone supplying the neighbouring layered series. The more complete of these is the Eastern Layered Series in which 16 conformable units can be distinguished. Others are presumed either to lie unseen at depth or to have been stripped by erosion. The Central Series, although often neglected because of its relative inaccessibility and complexity, formed from successive magma replenishments alternating with large-volume side-wall collapses of previously deposited cumulate material. It could thus be thought of as representing the ‘pulsing heart’ to the Rum volcano and deserves to be regarded as a site of major volcanological and petrological importance. Here we present a summary of some 60 years of investigation into the cumulate rocks of the Central Series.

Recent excavations at the site of Vermont's historically important Parker Quarry, long considered worked out where fossils were concerned, have yielded not only spectacular lower Cambrian trilobites but also soft-bodied animals including the early chordate Emmonsaspis cambrensis and a new multi-segmented bivalved arthropod Vermontcaris montcalmi. The first radiodont specimen from the locality indicates the presence of one of these apex predators more than 30-cm long. New discoveries from this Burgess Shale-type deposit add to our knowledge of the geographical diversity of animals that evolved during the Cambrian explosion.

One of the most notable events in the history of palaeoanthropology was the description of ‘Piltdown Man’, a hoax that took 40 years to uncover. At the centre of this episode was Sir Arthur Smith Woodward, who was duped by the ‘discoverer’ and fossil forger, Charles Dawson. Smith Woodward never doubted the authenticity of this find and died before the dénouement of the Piltdown episode. His last major work was a summary of Piltdown Man and its associated ‘science’. The Earliest Englishman is well-written and crafted, and still is worthy of being read at the present day, 70 years since the forgery was exposed.

The Arden Sandstone Formation of central and western England is a thin but conspicuous arenaceous unit within the Late Triassic Mercia Mudstone Group. Sedimentological and palaeontological data point to lacustrine depositional conditions, in contrast to the red desert mudstones above and below which were deposited as continental dryland desert floodplains. The Arden Sandstone records deposits of the lake margins and may be the high stand lateral equivalent of the halite and gypsum deposits which formed in the lake centre. The Carnian age of the Arden Sandstone potentially links it to the Carnian Pluvial Episode, marking the coalescence, spread and freshening of the formerly saline desert lakes, and deposition of sandy, fluvial and lacustrine deposits, during the wetter climate that prevailed for at least a million years.

There are key patterns of variation in the (litho-) stratigraphical record, which, with advances in computing technology in recent decades, have become amenable to objective numerical analysis. This research has chiefly focused on the search for spatially regular cycles in the sedimentary rock record, since there are theoretical grounds for believing that these would be periodic and thus provide a means of time-calibrating the stratigraphical records in which they occurred. Less popular lines of research consider the scaling relationships of the tangible, measurable sedimentary rock layers, and of the hiatuses, individually of indeterminate length, that punctuate these layers. Objective source data for all these analyses is provided, on limited (usually decametre) scales, by detailed lithological logging, sampling and dating of sections provided by exposures and cores. An objective global lithostratigraphical database, with larger, kilometre scales, is provided by the widespread practice of electric (wire-line) logging of deep wells. This involves measurement, at 6-inch (~15 cm) depth intervals of lithology-related petrophysical properties. Rapid desk top computer analysis of the hundreds or thousands of readings that comprise these two data series, searches for patterns of variation. This review considers the published evidence for ‘ubiquitous’ cyclicity and its use in chronostratigraphy, despite the contrary claims that stratigraphical records are predominantly random in character.

The Oxford University Museum of Natural History (OUMNH) is now celebrated as one of the most important Gothic revival buildings of the nineteenth century. It is also a temple of science. Built between 1855 and 1860, the design of the museum building incorporated input from artists, scientists and cultural figures such as the writer, philosopher, art critic and polymath John Ruskin. The aim of the museum's founders was to teach science—and that the museum building itself should serve as a teaching tool. Geology played a key role in achieving this.