Archean microfossils showing cell division from the swaziland system of South Africa.

A newly discovered population of organic walled microstructures from the Swaziland System, South Africa, is considered to be biological on the following grounds: (i) the structures are carbonaceous and occasionally have internal organic contents; (ii) the population has a narrow unimodal size frequency distribution (average diameter, 2.5 micrometers; range, 1 to 4 micrometers); (iii) the structures are not strictly spherical, but are commonly flattened and folded like younger microfossils; (iv) the sedimentary context is consistent with biogenic origins; and (v) various stages of binary division are clearly preserved.

Alga-like fossils from the early precambrian of South Africa.

Micropaleontological studies of carbonaceouis chert from the Fig Tree Series of South Africa (> 3.1 x 10(9) years old) revealed the presence of spheroidal microfossils, here designated Archaeosphaeroides barbertonensis, interpreted as probably representing the remnants of unicellular alga-like organisms. The presumed photosynthetic nature of these primitive microorganisms seems corroborated by organic geochemical and carbon isotopic studies of the Fig Tree organic matter, and is consistent with the geologically and mineralogically indicated Early Precambrian environment. These alga-like spheroids, together with a bacterium-like organism previously described from the Fig Tree chert, are the oldest fossil orgisms now known.

Fossil maize from panama.

Wild maize, agricultural maize, and associated Manihot fossil polleni indicative of early agriculture after about 7300 years ago have been discovered in the Gatun basin, Panama. The course of risinig sea level in the Canal Zone during the past 11,300 years is calculated.

Microorganisms three billion years old from the precambrian of South Africa.

A minute, bacterium-like, rod-shaped organism, Eobacterium isolatum, has been found organically and structurally preserved in black chert from the Fig Tree Series (3.1 x 10(9) years old) of South Africa. Filamentous organic structures of probable biological origin, and complex alkanes, which apparently contain small amounts of the isoprenoid hydrocarbons pristane and phytane, are also indigenous to this Early Precambrian sediment. These organic remnants comprise the oldest known evidence of biological organization in the geologic record.

Micropaleontological study of lunar material.

Samples of the lunar dust, rock chips, and thin sections of rocks from Tranquillity Base have been examined by use of white light and electron optics. In transmitted and in dark-and bright-field incident light and in the scanning electron beam the material reveals no indication of biological morphology. It is inferred that the lunar regolith has always been devoid of life. section preparations.

Freshwater peat on the continental shelf.

Freshwater peats from the continental shelf off northeastern United States contain the same general pollen sequence as peats from ponds that are above sea level and that are of comparable radiocarbon ages. These peats indicate that during glacial times of low sea level terrestrial vegetation covered the region that is now the continental shelf in an unbroken extension from the adjacent land areas to the north and west.

Precambrian age of the Boston basin: new evidence from microfossils.

A Vendian (Late Proterozoic Z) age has been determined for the Boston Basin by comparison of a microflora from the Cambridge Argillite with other late Precambrian assemblages. The microfossils, which include Bavlinella cf. faveolata, are preserved as petrifactions in pyrite. This age designation for the sedimentary rocks of the Boston Basin should allow for the reinterpretation of the structure of the basin and its regional correlations.

Ambient pyrite in precambrian chert: new evidence and a theory.

Ambient pyrites of two distinct types were described from middle Precambrian rocks of the Lake Superior area. A new class of this phenomenon is here described from middle Precambrian chert from western Australia. The newly found ambient pyrites are quite minute and characteristically occur in groups forming a "starburst" pattern. All three types of ambient pyrite may be explained in terms of pressure solution initiated by gas evolution from organic material attached to the pyrite. Thermal degradation of the kerogen produces the gases which, due to the impermeability of the encompassing chert, build up the pressures necessary to initiate solution. Pyrite appendages bear a striking resemblance to micro-organisms and, thus, constitute the smallest pseudofossils known.

A gunflint-type microbiota from the Duck Creek dolomite, western Australia.

Two billion year old black chert lenses from the Duck Creek formation, northwestern Western Australia, contain abundant organically preserved microorganisms which are morphologically similar to fossils of approximately the same age from the Gunflint formation, Ontario. Entities include: a relatively small (5-15mum) coccoid taxon morphologically comparable to Huroniospora Barghoorn, a larger coccoid form comparable to an apparently planktonic alga from the Gunflint, Gunflintia Baghoorn, and Eoastrion Barghoorn (Metallogenium Perfil'ev). Gunflint-type assemblages had a wide geographic distribution in middle Precambrian times, and these assemblages may eventually prove useful as biostratigraphic indices.

Paleopleurocapsa wopfnerii gen. et sp. nov.: A Late Precambrian alga and its modern counterpart.

Silicified dolomite of the approximately one billion year old Skillogalee Dolomite of the Adelaide Geosyncline, South Australia, contains organically preserved microfossils of a structurally complex, crustose pleurocapsalean cyanophyte, herein described as Paleopleurocapsa wopfnerii. Although actual cell contents have been degraded, lamellar sheath material faithfully preserves the morphology of the alga. Comparison with specimens of the modern genus Pleurocapsa Thuret demonstrates affinities at the family level and quite possibly even generic identity.

The Viking Mission: implications for life on Mars.

The results of the Viking Biology experiments are best explained by non-biological phenomena: The interaction of the reagents with the materials comprising the regolith. Conditions of water activity, temperature, availability of carbon sources and others in most regions of the planet are too extreme for survival and growth of any known Earth microorganisms. Although the possibility persists that some very unusual form of life is somewhere on that planet the evidence is best interpreted as negative. Even though there is no evidence for current life on Mars, whether or not life ever originated there is not known.