Paleontology

ABSTRACT Internal waves occur nearly ubiquitously in lakes and oceans yet their sedimentary records remain largely unrecognized. Waves propagate at the interface between fluids of different densities. Surface waves propagate at the interface between air and water, which is a strong density gradient. Internal waves propagate along weaker gradients (pycnoclines) within density-stratified fluids, behaving similarly to surface waves but typically at lower frequencies and larger amplitudes. Internal waves that occur at tidal frequencies are called internal tides; they are very common on the outer continental shelf and slope, and are generated as the surface tides move stratified water up and down a sloping surface. Large internal solitary waves known as solitons are ubiquitous wherever strong currents and stratification occur in the vicinity of irregular topography. These waves can force short-period, strong bottom-current pulses and may trigger upslope-surging vortex cores of dense fluid (boluses) that can induce mobilization of bottom sediments.Internal-wave deposits (internalites) are highly variable and definitive criteria for recognition are still to be developed. In terrigenous-clastic systems and shallow-water settings, internalites can be seen as "out-of-context" tempestites, detached from shore-related deposits and lacking thickening/coarsening upward sequences. In contrast to surface storm waves, the impact of internal waves is usually strongest in mid-outer-shelf regions and weaker in shallow water. Internal waves also provide a plausible mechanism to explain the origin of hummocky cross-stratification, especially their occurrence in different depositional environments. In deeper settings (continental slopes and canyons), internalites may have sedimentary structures indicating tidal currents and may coexist with turbidites. In carbonate systems, internal waves influence both sediment remobilization and the carbonate-producing biota. Differentiation between internal waves and surface storm waves is more reliable because many skeletal constituents have specific bathymetric distributions. Moreover, internal waves influence nutrient, plankton and larval distributions while inducing thermal variations by vertical displacements of the thermocline. The sharp gradient in nutrients and the chlorophyll-maximum zone typically correspond with the base of the seasonal pycnocline, which is commonly in the lower part of the photic zone. Suspension-feeding metazoans can thrive near the pycnocline, which explains the common occurrence of Phanerozoic metazoan buildups at mid- and outer ramp settings. During paleoceanographic changes that have influenced ocean stratification, internal waves may also have been a mechanism influencing diversification and extinction of these mid- and outer-ramp benthic communities.

L’interazione tra esseri viventi e ambiente è notoriamente oggetto di studio della biologia evoluzionistica; tuttavia, la prospettiva di ricerca inaugurata dalla niche-construction perspective entra di fatto in contrasto con la più convenzionale teorizzazione dell’evoluzionismo stesso: chiarire in sede di introduzione questa divergenza teorica risulterà fondamentale per le argomentazioni svolte nel presente lavoro.

It was in 1972 when Thomas J. Schopf (Fig. 1) and a bunch of fellows thought the time was ripe to thrust their paleontological form of mind into the body of evolutionary biology. It all started with a Symposium in 1970, and then a book, both entitled “Models in paleobiology”: “Implicit in it [the book] is the belief of the group [Schopf et al.] that paleontology has collected much of its data and basic theses. Explicit is the belief that henceforth paleontologists should turn to broader horizons and interpretive themes” (Schopf, 1972, p. 4). Central to the lasting fame of that book was the chapter dedicated to speciation. The one paper that actually hit the target was entitled “Punctuated Equilibria: An Alternative to Phyletic Gradualism”, written by Niles Eldredge and Stephen J. Gould [continues]

Sono raccolti i primi articoli della rivista "Il Radiologo" (2010-2018).
La paleoradiologia si usa per rispondere alle domande che l’antichità – o meglio il passato, talvolta anche quello prossimo – ci pone. A queste domande rispondono, insieme, gli archeologi, i medici, i biologi, gli antropologi, gli storici. Sono i nuovi paleoimager che studiano le tante questioni che la bioarcheologia presenta.
Una importante differenza di carattere lessicale, talvolta origine di incomprensione, deriva dal fatto che nei paesi anglosassoni il termine bioarchaeology riguarda esclusivamente lo studio dei resti ossei umani, mentre per noi la «bioarcheologia» è la disciplina che si occupa in senso lato dello studio dei resti organogeni, sia animali che vegetali, recuperati in un contesto archeologico.

... Ciancio published a number of scientific papers dealing with Fortis' biography [6], style and methods of scientific research [2], relationship between Fortis and other important 18th-century scientists and naturalists [4], and in 1995, he published a ... 3. Alberto Fortis (1741–1803). ...

This chapter deals with fishing and archaeology. Knowledge held by fishermen has contributed to underwater archaeology's great moments. It is comparable to 'local' knowledge on land, although the locales may be far offshore. To some extent, fishing interests and the management of underwater cultural heritage are at odds but hardly as much as sometimes claimed. Future cooperation with fishermen is of the essence, as the fishing industry has been an essential informer for the development of archaeology offshore, all over the world, and continues to be so. This chapter explores how the development of fishing techniques over the last 150 years has informed prehistoric archaeology of the European continental shelves, notably of the North Sea. It does so through a historical analysis of technological development in its social setting and by highlighting some developments in Dutch fishing communities. It puts collecting of bones and trade in antiquities in perspective. It is mostly concerned, however, with the contingent knowledge base of archaeology and therefore informs archaeological epistemology.

For years, scientists have been puzzled by the mysterious "sailing stones" of Death Valley.

Located in a remote area of California's Death Valley National Park, the heavy stones appear to move across the dried lake bed known as Racetrack Playa, leaving a trail behind them in the cracked mud.

The rocks' apparent movement has been blamed on everything from space aliens and magnetic fields to pranksters. But no one has actually seen the rocks move, which only adds to the mystery.

Scientists have tried to solve the puzzle of the sailing stones for decades. Some researchers thought that dust devils might move the rocks, some of which weigh as much as 700 lbs. (318 kilograms).

Apparently these stones contain an ancient DNA, which seems to be activated at certain times. Some natives claim that these are physical remains of a giant race.

"People always ask, 'What do you think causes them to move?' But if you try to explain, they don't always want to hear the answers,".
"People like a mystery — they like an unanswered question".

In marine geology, a guyot (also known as a tablemount) is an isolated underwater table mountain (seamount) with a flat top more than 200 m (660 ft) below the surface of the sea. The diameters of these flat summits can exceed 10 km (6.2 mi).
Guyots are most commonly found in the Pacific Ocean, but they have been identified in all the oceans except the Arctic Ocean.
Guyots show evidence of having once been above the surface, with gradual subsidence through stages from fringed reefed mountain, coral atoll, and finally a flat-topped submerged mountain.

Nel presente contributo sono trattati e discussi per la prima volta in modo sistematico e organico gli elementi geologici rintracciabili nell'opera Il Tesoro di Brunetto Latini. Oltre riferimenti strettamente geologici, nel testo sono presi in considerazione anche aspetti di carattere più generale, includendo anche richiami di cosmologia e scienze naturali sensu lato. Nell'opera Il Tesoro, che può essere considerata a tutti gli effetti la prima vera enciclopedia volgare, Latini costruisce un importante ponte conoscitivo tra le ipotesi su temi naturali del mondo antico e lo stato delle conoscenze caratterizzante il Medioevo. Autori di riferimento per l'opera del fiorentino sono sicuramente Aristotele e Tolomeo, con il tentativo, sposato successivamente dal discepolo Dante Alighieri, di integrare il pensiero cristiano con la filosofia aristotelica, seguendo dunque le orme di Alberto Magno e Tommaso d'Aquino. Gran parte della lettura dei fenomeni naturali sono presi in prestito da Latini direttamente dai Metereologica di Aristotele, senza nuove letture dei processi o cambi interpretativi maggiori. L'analisi dell'opera di Latini sottolinea nuovamente come il Medioevo non rappresentò l'età oscura per antonomasia per la scienza ma, diversamente, il periodo in cui vennero posti quei quesiti fondamentali per la successiva rivoluzione scientifica vera e propria.

The reason for the extinction of the Neandertals in Western Europe, and especially the question of whether AMH played an active role in their demise, is one of the most controversial issues in prehistoric research.
This thesis aims to present and test a hypothesis that the megafaunal extinction that began some 50 Kya in Western Europe played a significant role in the extinction of the Neandertals.
A natural decrease in plant food availability during the long and harsh MIS 3 winters in Western Europe lead to the conclusion that Neandertals relied to a significant extent on animal-sourced food, especially during winters. A physiological ceiling on their protein consumption, coupled with the limited availability of plant food, must have forced Neandertals to depend on the acquisition and consumption of a substantial amount of animal fat. This obligatory amount of fat could only be supplied by acquiring large animals which contain, relatively, a higher proportion of calories from fat than smaller animals and even more so during harsh winters. When large animals diminished, a chronic energetic stress developed which could have caused the extinction of the Neandertals.