Site formation processes and vertical stratigraphy in Finland

The absence of vertical stratigraphy from the majority of Finnish Stone Age sites has been a given through most of our research history. The only generally acknow ledged stratigraphic dimension has been "horizontal stratigraphy", or the gradual chronological change following the elevations of the sites above the present sea level. The accepted model of the formation of thick cultural layers has been the penetration of the material deeper and deeper into the soil through trampling during long-term or recurrent occupation. This paper attempts to show through examples drawn from experimental archaeology and from the analyses of the Ala-Jalve site in Utsjoki that there is a maximum limit to the penetration achieved through trampling, and that the formation of cultural layers exceeding the maximum trampling thickness requires other explanations. Understanding the formation processes of cultural layers is essential for accurate site analyses. The Ala-Jalve results show that the possibility of vertical stratigraphy is worth taking into account even on sites where no distinct layers are visible in the section

The compositional and evolutionary logic of metabolism

Metabolism displays striking and robust regularities in the forms of modularity and hierarchy, whose composition may be compactly described. This renders metabolic architecture comprehensible as a system, and suggests the order in which layers of that system emerged. Metabolism also serves as the foundation in other hierarchies, at least up to cellular integration including bioenergetics and molecular replication, and trophic ecology. The recapitulation of patterns first seen in metabolism, in these higher levels, suggests metabolism as a source of causation or constraint on many forms of organization in the biosphere. We identify as modules widely reused subsets of chemicals, reactions, or functions, each with a conserved internal structure. At the small molecule substrate level, module boundaries are generally associated with the most complex reaction mechanisms and the most conserved enzymes. Cofactors form a structurally and functionally distinctive control layer over the small-molecule substrate. Complex cofactors are often used at module boundaries of the substrate level, while simpler ones participate in widely used reactions. Cofactor functions thus act as "keys" that incorporate classes of organic reactions within biochemistry. The same modules that organize the compositional diversity of metabolism are argued to have governed long-term evolution. Early evolution of core metabolism, especially carbon-fixation, appears to have required few innovations among a small number of conserved modules, to produce adaptations to simple biogeochemical changes of environment. We demonstrate these features of metabolism at several levels of hierarchy, beginning with the small-molecule substrate and network architecture, continuing with cofactors and key conserved reactions, and culminating in the aggregation of multiple diverse physical and biochemical processes in cells.Comment: 56 pages, 28 figure

Anthropogenic contributions to global carbonyl sulfide, carbon disulfide and organosulfides fluxes

Previous studies of the global sulfur cycle have focused almost exclusively on oxidized species and just a few sulfides. This focus is expanded here to include a wider range of reduced sulfur compounds. Inorganic sulfides tend to be bound into sediments, and sulfates are present both in sediments and the oceans. Sulfur can adopt polymeric forms that include S-S bonds. This review examines the global anthropogenic sources of reduced sulfur, updating emission inventories and widening the consideration of industrial sources. It estimates the anthropogenic fluxes of key sulfides to the atmosphere (units Gg S a-1) as: carbonyl sulfide (total 591: mainly from pulp and pigment 171, atmospheric oxidation of carbon disulfide 162, biofuel and coal combustion, 133, natural 898 Gg S a-1), carbon disulfide (total 746: rayon 395, pigment 205, pulp 78, natural 330 Gg S a-1), methanethiol (total 2119: pulp 1680, manure 330, rayon and wastewater 102, natural 6473 Gg S a-1), dimethyl sulfide (total 2197: pulp 1462, manure 660 and rayon 36, natural 31 657 Gg S a-1), dimethyl disulfide (total 1103: manure 660, pulp 273; natural 1081 Gg S a-1). The study compares the magnitude of the natural sources: marine, vegetation and soils, volcanoes and rain water with the key anthropogenic sources: paper industry, rayon-cellulose manufacture, agriculture and pigment production. Industrial sources could be reduced by better pollution control, so their impact may lessen over time. Anthropogenic emissions dominate the global budget of carbon disulfide, and some aromatic compounds such as thiophene, with emissions of methanethiol and dimethyl disufide also relatively important. Furthermore, industries related to coal and bitumen are key sources of multi-ringed thiophenes, while food production and various wastes may account for the release of significant amounts of dimethyl disulfide and dimethyl trisulfide

Proterozoic, Archeam and other weeds in the Precambrian rock garden

The use of the terms Precambrian; Proterozoic, Algonkian, and Archean; Cryptozoic and Archeozoic; and Eocambrian, Infracambrian, and Subcambrian is discussed. The Precambrian is no System in the sense of the Phanerozoic Systems but should be retained as the name of the longest recognized geochronologic unit and of the most extensive chronostratigraphic unit. A survey of literature and personal information received from Precambrian geologists in many parts of the world shows that the estimated age of the Proterozoic-Archean boundary ranges from about 3 000 Ma to about 1 700 Ma. The boundary is reasonably expected to be a worldwide isochronous boundary to which all Precambrian stratigraphers can return for reference. Unfortunately, it is not an isochronous boundary, and consensus as to its age seems to be impossible to reach. The Proterozoic and the Archean are recognized as valid terms only in their originally defined type areas. Their continued use as worldwide subdivisions of the Precambrian is not recommended. The other terms discussed are ill-defined, confusing, and meaningless. They should be discarded

Late Precambrian glaciogenic sedimentary rocks in southern Africa: a compilation with definitions and correlations

Evidence of ancient glaciations is summarized, and the terminology dealing with glaciogenic and nonglaciogenic sedimentary rocks is discussed. The term tillite is used as a comprehensive genetic term for both continentally deposited and ice-rafted indurated tills. The glaciogenic origin of any rock called tillite must have been proved beyond doubt. The term mixtite is used for sedimentary rocks that resemble tillites but are of uncertain or unknown origin. A comprehensive compilation of all known Late Precambrian glaciogenic sedimentary rocks in South Africa and in South West Africa is presented. These rocks seem to form two distinct groups that may indicate the existence of two periods of glaciation. Glaciogenic rocks in other countries in Africa occupy similar stratigraphic positions. This evidence strengthens the possibility of the existence of a severe continentwide Late Precambrian glaciation in Africa. Comments on the Late Precambrian glaciation in Australia and in South America are given