Biofacies and taphonomic analysis has allowed for the reconstruction of the paleoenvironmental history of accumulation of a series of spectacular mollusk-dominated shell-concentrations from the Puerto Madryn Formation and the benthic assemblages that inhabited the Miocene sea in northern Patagonia, Argentina. An upward-shallowing from open mid-shelf to more restricted shoreface-foreshore environments has been recognized. Transgressive, Maximum Highstand and Regressive phases are recognized based on the integrated approach of assemblages and lithofacies arrangement. Eleven mollusk-dominated fossil assemblages were defined and grouped into Associations A, B, and C. Transgressive and Maximum Highstand phases preserve three main shell beds that record an upwards change from dynamic to complete bypassing conditions. These were deposited in tidal current-dominated mid- and inner-shelf environments and belong within Association A. The top bedding surface records the maximum depth attained by the sea. The Regressive Phase is characterized by three upward-deepening cycles comprised of foreshore-shoreface sandbar deposits containing Association C. Sandbars are capped by environmentally condensed shell-beds of Association B and record deposition from the shoreface (wave-breaking zone) to mid-shelf environments, all above storm-wave base.

Based on these fossil assemblages, seven benthic life associations can be identified. The deepest ones inhabited the mid-to-inner shelf and were represented by suspension-feeders from gravel-substrata swept by strong tidal currents and by suspension-feeders from lower energy firm bottoms. Lower shoreface sandy bottoms, close to fairweather wave base and affected by weak tidal currents, were inhabited by epifaunal suspension-feeders, whereas sandy bottoms close to the fairweather wave-breaking zone were characterized by semi-infaunal deposit feeders and suspension feeders. The shallowest living assemblages inhabited intertidal and foreshore settings and were represented by soft-bottom infaunal suspension feeders, as well as by firm bottom, vagile carnivorous and suspension-feeding epifauna.

The sensitivity of taphonomic signatures to a battery of common sampling and analytic procedures is tested here using modern bivalve death assemblages from the San Blas Archipelago, Caribbean Panama, to determine (a) the magnitude of methodological artifacts and, thus, the comparability of taphofacies patterns among studies; and (b) the most efficient and robust means for acquiring damage profiles (taphonomic signatures) of death assemblages both ancient and modern. Damage frequency distributions do not stabilize below sample sizes of 120–150 individuals. Using damage to the >8 mm portion of the assemblage as a baseline (interior damage only, fragments included), it is found that qualitative trends among environments (higher damage levels in reefal skeletal gravel versus mud) and the rank-order importance of taphonomic variables per environment (intensity of damage from encrustation, boring, fine-scale alteration, edge-rounding, fragmentation) are robust to most methodological decisions. The exception is the use of target taxa: of three genera tested, only one was sensitive to the same suite of environmental differences as the total-assemblage, and taxa had disparate rank-ordering of variables. In contrast to the general robustness of qualitative trends, quantitative damage levels are affected significantly by methodology. Specifically, the measured frequency of damage is generally lower for finer size fractions and finer sieve sizes, for whole shells versus fragments, for taxonomically well-resolved specimens, for infaunal versus epifaunal species regardless of mineralogy, and for interior surfaces versus exterior or total surface area of shells. Full frequency-distribution data on states of taphonomic damage are most powerful for differentiating samples, but if single-value metrics are desired, the frequency of high-intensity damage is more powerful—and shows less between-operator variance—than presence-absence data or average damage state. To maximize the detection of damage and of between-environment differences in taphonomic signature, and to foster between-study comparisons, the following are recommended: (1) analysis of discrete size-fractions rather than broad spectra and, in particular, the separate treatment of coarse size fractions (>4 mm); (2) examination of complete assemblages (fragments as well as whole specimens; all species or broad subsets of species rather than select taxa); (3) variables scored independently (e.g., encrustation v. boring) rather than grouped into summary grades; and (4) evaluation of rank-ordering of variables in plots of threshold damage profiles as a complement to ternary taphograms.

Living and death assemblages of selected benthic, symbiont-bearing foraminiferal species were compared at a NW-Pacific island slope. Two transects with different morphologies were chosen, one demonstrating decreasing, the other slightly increasing, steepness. Intensities of depth transport were estimated by measuring the differences between distribution parameters of living individuals and empty tests. Three factors were shown to induce depth transport: (1) traction caused by offshore bottom currents or the frequent tropical cyclones that cross the area, (2) slope steepness, and (3) differences in test buoyancies. Due to the depth position of living populations, the combination of these three factors leads to varying displacement intensities and mixing of empty foraminiferal tests.

The two investigated larger foraminiferal species with porcelaneous tests living at the shallow slope—the rod-shaped Alveolinella quoyi (d'Orbigny) and the discoid Amphisorus hemprichii Ehrenberg—showed high buoyancy and are transported commonly down slope. Less displacement was found in Heterostegina depressa d'Orbigny, which inhabits the upper slope, and this is due to a lower test buoyancy. The thick-lenticular Nummulites venosus (Fichtel and Moll) and the spherical Baculogypsinoides spinosus Yabe and Hanzawa, both living in deeper regions, are transported less often, while Cycloclypeus carpenteri Brady, with a similar depth distribution, shows a high degree of transport to the deepest zone as the result of high buoyancy. The deepest-living species in this study, Planostegina operculinoides (Hofker), is not transported, but accumulates under conditions of reduced sedimentation.

The complex slope topography, combined with the exposure of the coast to tropical storms, leads to deposition of allochthonous specimens from surrounding shallow areas. Specimens from backreef regions are transported into the forereef during waning storms (e.g., Amphisorus hemprichii), while elements of relict sediments are reworked on the deeper slope during these episodic events. Although both factors, in combination with down-slope transport and slope inclination, disguise the clear depth dependence of larger foraminifers as shown by living individuals, representative proportions of the deepest-living species within an association of empty tests allows for the approximation of the upper depth limit.

Siliceous stalactites, formed of opal-A laminae that are concentrically arranged around a hollow soda-straw, are common features structures in some of the geyser and hot spring deposits at Whakarewarewa and other geothermal areas of New Zealand. These siliceous stalactites contain diverse biota of bacteria (including cyanobacteria), fungi, and diatoms that lived on the stalactite surfaces, with locally abundant pollen grains, and springtails. The microbes are the templates for much of the opaline silica precipitation and thereby controlled most of the fabrics that form the stalactite laminae.

Siliceous stalactites form at sites of dripping water below the overhanging edges of geyserite rims that surround geyser vents, and along the steep margins of sinter terraces on discharge aprons. Stalactites may hang as isolated individuals or may coalesce to form dripstone draperies along terrace or rim margins. Stalactite growth is controlled by the volume, temperature, and the silica concentration of the water supplied to the growth site. These waters mainly originate from geyser or hot spring discharge. The microbes preserved in the stalactites, however, imply that silica precipitation took place after these waters had cooled.

The growth and coalescence of geyser stalactites to form complex dripstone draperies plays an important role in the lateral accretion of sinter around the rims of many geysers and in progradation of sinter terraces.

Disaster taxa are long-ranging opportunistic generalists that briefly proliferate in the aftermath of mass extinctions, invading vacant ecospace until forced to return to more marginal settings through competition with specialist taxa returning from refugia. Lowermost Triassic (Griesbachian) strata worldwide have been noted for a brief ‘proliferation of Lingula’, a classic ‘living fossil’, which through its long fossil record typically has occurred in shoreface and dysoxic settings. The abundance of Lingula relative to other taxa in the Griesbachian Dinwoody Formation of southwestern Montana and western Wyoming (USA) has been quantified and the results placed into a paleoenvironmental context. Lingula dominates the fossil assemblage in the Dinwoody Formation across several facies deposited on an oxygenated, storm-dominated, mixed carbonate/siliciclastic shelf. A study of preservational state and quality further indicates that these results are not due to taphonomic bias. Lingula, therefore, behaved as a disaster taxon during the biotic recovery from the end-Permian mass extinction, much like relatively common Early Triassic normal marine stromatolites, that have been interpreted as disaster forms. Thus, while the fundamental rules of geology and biology have not changed, during biotic recoveries from mass extinctions organisms may behave and interact with their environments very differently than do their modern or fossil equivalents in “normal” times.

A fossil woodland/forest in Upper Cretaceous strata of the Aguja Formation in Big Bend National Park, Texas, preserves two species of dicotyledonous trees with trunks up to 1.3 m in diameter. The straight buttressed trunks, absence of low branching, and lack of distinct growth rings suggest that these trees represent a tropical evergreen community having a canopy height of 40 to 50 m. Well before the end of Cretaceous time, dicotyledonous angiosperms were the dominant canopy forming trees in at least some ecosystems in North America. These trees may have been among the woody plants that produced the Normapolles palynoflora.