Bioturbation long has been ‘blamed’ for eliminating late Proterozoic-style sedimentary structures and fabrics. While the presence of diverse and complex burrows in lowermost Cambrian strata is indisputable, analysis of Precambrian–Cambrian successions in southeast Newfoundland demonstrate that this burrowing style did not produce typical Phanerozoic-style ichnofabrics.

Three hundred meters of the siltstone/sandstone facies of member 2 of the Chapel Island Formation were examined in the area of the Precambrian–Cambrian boundary stratotype. Gyrolithes, Planolites, and Skolithos occur as sand infills ubiquitously throughout siltstone beds, most commonly without direct contact with an overlying sandstone bed, as if “floating” in the siltstone. In contrast, Treptichnus pedum occurs as sand infills adhering onto the base of thin sandstone beds that have different grain size and texture than the burrow infills. Both of these burrow types represent a style of preservation in which the burrows are unattached to an overlying bed of the casting sediment. These styles of preservation occur frequently in the Treptichnus pedum Zone and continue into the Rusophycus avalonensis Zone in spite of an increase in trace fossil diversity. The sandstone beds are bioturbated only very rarely. The resultant fabric produced by floating and, in particular, adhering burrows in these shallow marine deposits appears to be characteristic of many Lower Cambrian rocks. Silt layers appear to have been firm enough to have supported open burrows, likely as a result of a negligible mixed layer. This line of reasoning would predict that preservation of this type would be uncommon in younger strata deposited in open marine settings.

Integrated analysis of the ichnology, sedimentology, geochemistry, and fossil content of three trace fossil-bearing calcareous paleosols from the early Eocene Gran Salitral Formation is used to reconstruct the detailed paleoenvironmental and paleoecological setting of this insect-dominated ichnofossil association. This continental sequence, located in southwestern La Pampa province (Argentina), is composed of palustrine marls and minor lacustrine mudstones and sandstones arranged in shallowing-upward cycles. The ichnologic association is the first comprehensively described from a palustrine sequence and could be used for future comparisons with other similar assemblages. The ichnofauna is dominated by bee cells, Celliforma germanica, C. roselli, and Rosellichnus isp.; Teisseirei barattinia, an insect trace fossil that is redescribed and recorded for the first time outside its type locality; Taenidium barretti; and Skolithos linearis. The ichnologic association also includes ovoid structures, ornamented burrow fillings, and plant trace fossils (rootlets, rhizoliths, and a tree / shrub stump). Abundant freshwater (Pomacea sp.) and terrestrial gastropods (Plagiodontes spp., Bostryx sp., and Bulimulus sp.) are used to characterize the paleoenvironmental setting. The weakly developed paleosols are interpreted as Inceptisols, developed in a low-gradient lake margin periodically exposed to pedogenesis with low (probably saline) vegetation and sparse shrubs. They developed under a semi-arid and warm climate (mean annual temperature higher than 20°C). Short saline / alkaline conditions were prevalent during lake lowstands, accompanied by incipient karst development. The association of trace fossils is attributed provisionally to the Coprinisphaera ichnofacies, although its distinctive features and recurrence in time and space may deserve recognition as a separate ichnofacies.

The presence of original organic matter and retention of an indigenous isotopic signal in fossils have been disputed for years. An experiment was conducted to evaluate the influence of diagenesis on bone-protein isotope values, analyses were conducted on Holocene and Pleistocene fossils from Natural Trap Cave (NTC), Wyoming. Modern cow, Bos taurus, bone was heated with and without excess water for up to 195 hours at 100°C in an inert atmosphere. Collagen and non-collagenous proteins (NCP) were extracted and analyzed isotopically. Under dry conditions, carbon and nitrogen isotope values change by less than 0.4‰ during the 0 to 195 hour interval. In the presence of excess water, carbon and nitrogen isotope values change by no more than 1.0‰ and 0.5‰, respectively, over 192 hours. The relative abundance of amino acids of collagen from heated bone differs by less than 10% from that of unheated collagen. Protein preservation is indicated by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) that strongly indicates a portion of the original osteocalcin exists intact in samples heated for 195 hours. Good preservation of collagen in NTC fossils is implied by high collagen yields, C:N, and realistic trophic structures based on isotope values. Carbon and nitrogen isotope values of ancient collagen increase with trophic level, allow dietary assessments to be made, and differentiate between ruminant and non-ruminants. The results indicate that isotope values are resilient during simulated diagenesis and suggest that an indigenous isotopic signal can exist in well-preserved fossils such as those from NTC.

The Shelf and Slope Experimental Taphonomy Initiative (SSETI) Program was established to measure taphonomic rates in a range of continental shelf and slope environments. Experiments were deployed on the forereef slope off Lee Stocking Island, Bahamas, for one and two years along two transects (AA and BA) in seven distinctive environments of deposition (EODs) along each transect: in sand channels on the platform top (15 m) and the platform edge (30 m), on ledges down the wall (70–88 m), on the upper (183 m—transect BA only) and lower (210–226 m) talus slope below the wall, and on the crest (256–264 m) and in the trough (259–267 m) of large sand dunes.

Discoloration was by far the dominant taphonomic process over the two-year deployment period, with dissolution or maceration of shell carbonate a close second. Periostracum breakdown was not significant, nor was loss of shell weight. Chipped edges and breakage (assayed by the edge alteration variable) were much less common, but were important in some species. The degrees of edge alteration and dissolution were correlated with discoloration more frequently than expected by chance, emphasizing that the process of discoloration progressed in a coordinated fashion with the other two over time. The degree of burial or the interaction between degree of burial and water depth explained most of the trends observed in discoloration.

The deep water sites, below the photic zone, including the talus slope and dune EODs, had very similar taphonomic signatures. Shells were characterized by a low degree of discoloration, little edge alteration, and varying degrees of dissolution. Photic zone sites, including the platform top and wall locations, followed the opposite trends, with the shallowest site, on the platform top, typically attaining the most extreme degree of alteration. The wall location was most similar to the platform top despite the greater depth and less rigorous physical and sedimentological regime. The platform edge occupied an intermediate position, likely due to the greater degree of burial that resulted in shells at this site being at least as frequently under aphotic conditions as under photic conditions. The data indicate that similar taphonomic signatures can be attained in distinctly different ways over a two-year exposure period, complicating the interpretation of taphofacies and the taphonomic process.

The Shelf and Slope Experimental Taphonomy Initiative (SSETI) Program was established to measure taphonomic rates in a range of continental shelf and slope environments over a long period of time. For this report, mollusk shells were deployed for one and two years at seven different environments of deposition (EODs) along two onshore-offshore transects off Lee Stocking Island in the Bahamas. The experimental sites were located: in sand channels on the platform top (15 m) and the platform edge (33 m); on ledges down the wall (70–88 m); on the upper (183 m) and lower (210–226 m) talus slope below the wall; and on the crest (256–264 m) and in the trough (259–267 m) of large sand dunes. Shell condition was assessed using a range of taphonomic attributes including dissolution, abrasion, edge alteration, discoloration, and changes in shell weight.

After two years, taphonomic alteration was not particularly intense in any EOD. No species was particularly susceptible or resistant to taphonomic alteration. Taphonomic processes were unexpectedly complex. Effects of location, transect, water depth, and degree of exposure all had significant effects. On average, shells deployed in shallow sites were altered significantly from the controls more frequently than shells deployed at deeper sites. However, the number of significant interaction terms between time and the other main effects indicates a complex interaction between taphonomic processes and the local environment that, over the short term, defies any attempt at delineating taphofacies over a broader spatial area than a single deployment site. Some locations attained the same taphonomic signature in different ways making discrimination of taphonomic rules difficult. For example, deeper-water sites and shallow sites where burial rates were high yielded similar taphonomic signatures because shells were in the aphotic zone in both cases, and this limited the rate and range of taphonomic interactions. Taphonomic processes were strongly nonlinear in time for all taphonomic attributes in all species and all EODs. Nonlinear taphonomic rates hinder the interpretation of single-point-in-time studies in understanding the taphonomic process and buttress a commitment to long-term experiments.

Coniform stromatolites are found in several sites in the Tokaanu and Whakarewarewa geothermal areas of North Island, New Zealand. At Tokaanu, silicification of these stromatolites is taking place in Kirihoro, a shallow hot spring-fed pool. At Whakarewarewa, subfossil silicified coniform stromatolites are found on the floor of “Waikite Pool” on the discharge apron below Waikite Geyser, and in an old sinter succession at Te Anarata. The microbes in the coniform stromatolites from Tokaanu, Waikite Pool, and Te Anarata have been well preserved through rapid silicification. Nevertheless, subtle differences in the silicification style induced morphological variations that commonly mask or alter morphological features needed for identification of the microbes in terms of extant taxa.

The coniform stromatolites in the New Zealand hot-spring pools are distinctive because (1) they are formed of upward tapering (i.e., conical) columns, (2) neighboring columns commonly are linked by vertical sheets or bridges, (3) internally, they are formed of alternating high- and low-porosity laminae that have a conical vertical profile, and (4) Phormidium form more than 90% of the biota. As such, they are comparable to modern coniform mats and stromatolites found in the geothermal systems of Yellowstone National Park and ice-covered lakes in Antarctica.

Formation of the coniform stromatolites is restricted to pools that are characterized by low current energy and a microflora that is dominated by Phormidium. These delicate and intricate stromatolites could not form in areas characterized by fast flowing water or a diverse microflora. Thus, it appears that the distribution of these distinctive stromatolites is controlled by biological constraints that are superimposed on environmental needs.

Sandstones from the Black Island member of the Winnipeg Formation (Ordovician) contain a variety of early diagenetic iron sulfide morphologies, including elongate concretions of variable length. Examination of sandstone samples with X-radiography reveals that these concretions, now consisting of pyrite, are associated with burrows.

Detailed textural examination of the pyrite shows an anomalously loose packing of sand grains within these concretions, and also suggests that iron sulfide nucleation commenced at multiple sites in what must have been a stiff matrix. Compositional data acquired by electron microprobe indicate that the iron sulfides did not replace fecal matter left behind by the burrower. Sulfur isotope data point to bacterial sulfate reduction as a sulfide source, corroborated by fossilized bacterial remains within the concretionary pyrite.

Mucus and slime trails of marine benthos were probably important for early diagenetic pyrite production in these sediments; they can be considered a favorable “culture” medium for sulfate reducing bacteria. Because the mucus seems to mineralize very early in burial history, it also provides for enhanced preservation of bacterial remains.

Backscattered electron imaging of fossils exceptionally-preserved as organic compressions reveals anatomical details that are not evident either under incident light or in secondary electron images. The method can be used to differentiate between anatomical features that are superimposed, lack relief, and compressed essentially to a single plane. In situ observation is possible, removing the need to liberate the fossil from the matrix by either chemical or physical means, both of which have their limitations. Fossils exceptionally preserved, at least in part, as organic compressions are characteristic of a large number of Konservat Lagerstätten, and the method has significant potential for elucidating aspects of their morphology.