منابع مشابه
Models of diffusion-limited uptake of trace elements in fossils and rates of fossilization
Many fossils are assumed to take up trace elements by a process of combined diffusion plus adsorption (DA), yet in principle composition profiles can be explained by several different diffusion-limited processes, including diffusion plus reaction or recrystallization (DR) and double-medium diffusion (DMD). The DA and DMD models are supported by REE and U composition profiles across fossil teeth...
متن کاملEmergent Fossilization
Aging is an inescapable fact of human life. In most areas of our lives, aging leads to an unremarkable, gradual decline in physical ability. For example, no one questions why a 40-year-old runner can no longer compete in the Olympics. As the body ages, metabolism slows, joints wear out, and energy is diminished. Aging also has a uniform natural effect on the learning of new skills. As a result,...
متن کاملFossilization: five central issues
Second language acquisition research over the past three decades has generated a wide spectrum of different interpretations of “fossilization” – a construct introduced by Selinker (1972) for characterizing lack of grammatical development in second language learning. These conceptual differences found in the literature, it has become increasingly clear, create confusion rather than offering clar...
متن کاملFossilization of melanosomes via sulfurization
Fossil melanin granules (melanosomes) are an important resource for inferring the evolutionary history of colour and its functions in animals. The taphonomy of melanin and melanosomes, however, is incompletely understood. In particular, the chemical processes responsible for melanosome preservation have not been investigated. As a result, the origins of sulfur-bearing compounds in fossil melano...
متن کاملAlteration of Enamel Carbonate Environments during Fossilization
An understanding of enamel diagenesis is necessary to ensure sound isotopic palaeodietary and palaeoenvironmental reconstructions. Although carbon isotope signals of browsing and grazing herbivores remain distinct in enamel even after millions of years, subtle alteration of isotopic signatures does occur. To better understand this change we analysed modern and fossil enamel from a number of Sou...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The American Naturalist
سال: 1896
ISSN: 0003-0147,1537-5323
DOI: 10.1086/276499