Emerging transitions in organic waste infrastructure in Aotearoa New Zealand

Aotearoa New Zealand is at a critical juncture in reducing and managing organic waste. Research has highlighted the significant proportion of organic waste sent to landfills and associated adverse effects such as greenhouse gas emissions and loss of valuable organic matter. There is current debate about what practices and infrastructure to invest in to better manage and use organic waste. We highlight the diversity of existing organic waste practices and infrastructures, focusing on Auckland, Wellington and Christchurch. We show how debates about organic waste practices and infrastructure connect across three themes: waste subjectivities, collective action in place and language.     

Quantitative tests for stratigraphic cyclicity

Periodic Milankovitch (M-) orbital forcing provides an explanation for subjectively recognized short-term repetition of lithofacies-‘cycles’-in the stratigraphic record. Tests of this explanation often find no order in the lithofacies and/or no regularity in the recurrence of lithofacies. This does not disprove the influence of M-forcing, but a sedimentary response in terms of irregular M-forced ‘cycles’ is indistinguishable from one in which repetition of facies is not M-forced. Use of such cycles in time calibration is correspondingly suspect. Stricter, dimensional cyclicity invokes Sander's Rule, which suggests periodicity in sedimentation, for which M-forcing provides an obvious explanation. Time calibration on the basis of strict cyclicity thus appears more dependable. Objective tests for regular M-forced stratigraphic cyclicity commonly depend upon spectral analyses. Such tests are not unambiguous. Bilogarithmic thickness/frequency plots derived from objective layer thickness inventories (LTI) provide an alternative. Commonly, such plots show power-law relationships that preclude dimensional M-cyclicities. By contrast, a model data series that perfectly encodes the M-cyclic fluctuations in terrestrial insolation generates a strongly inflected, non-power-law LTI plot. Power-law plots result where the model data series is decimated by random hiatuses, with numbers and durations tuned to M-cycle frequencies. It seems improbable that natural data series record such tuning. The general absence of strict cyclicity in the M-frequency range is more likely to reflect the nonlinear response of sedimentary systems to cyclic M-forcing of insolation. Interestingly, when applied to the classically cyclic lacustrine Triassic sediments of the Newark Basin, USA, the LTI test suggests a decimated record, preserving some evidence of M-cyclicity. Copyright © 2008 John Wiley & Sons, Ltd.     

Polysomatism,polytypism, defect microstructures,and reaction mechanisms in regularly and randomly interstratified serpentine and chlorite

High-resolution (HRTEM) and analytical electron (AEM) microscopic evidence for a polysomatic series based on regular interstratifications of serpentine (amesite) and chlorite (clinochlore) are reported from an altered skarn in Irian Jaya. The assemblage includes regular interstratifications of one clinochlore and two (2:1; three structural variants), three (3:1), and four (4:1) amesite composition 1:1 layers as well as randomly interstratified serpentine and chlorite. The order of abundance of regularly interstratified minerals is 1:1>2:1>4:1>3:1. Atomic-resolution images, image simulations, and comparison between calculated and observed diffracted intensities verify the proposed 1:1 and 2:1 structures and reveal details of their defect microstructures. AEM data show that compositions are linear combinations of the associated amesite and clinochlore. The 1:1, 2:1, 3:1, and 4:1 minerals occur both as discrete sub-micron crystals and as domains within serpentine or chlorite. Some crystals of the 2:1 phase were sufficiently large for study by X-ray precession and powder methods. Crystals of the regularly interstratified 2:1, 3:1, and 4:1 phases are usually bent. High-resolution images reveal that, within polygonal segments, the layers commonly exhibit a few degrees of curvature with segments separated by antigorite-type offsets. Deformed chlorite crystals are probably replaced by interstratified minerals during an aluminum metasomatic event. Al may have been deposited from sulfuric acid-rich solutions when they interacted with calcite and dolomite to form the anhydrite-rich corona around the phyllosilicate-rich region of the core. The interstratified chlorite (clinochlore composition) suggests aluminum addition by selective conversion of a sub-set of the chlorite layers to amesite. Defect microstructures suggest that crystals of regularly interstratified material grew by direct structural modification of preexisting chlorite. Regular interstratifications may form in response to thermally controlled limits on Al solubility in chlorite and heterogeneities in the distribution of Al-rich solutions during metasomatism. Regularly interstratified minerals coexist with randomly interstratified serpentine/chlorite, chrysotile, antigorite, lizardite, and several amesite and chlorite polytypes. Tentative chlorite and amesite identifications include one-layer (b=97°, probably IIbb), one-layer (b=90, possibly Ibb), two-, and three-layer chlorites, and 2H₁ (but possibly 1M or 1T), rhombohedral (3R or 6R), and twelve-layer (Tc; non standard) serpentine polytypes. The complex phyllosilicates attest to rampant chemical and structural disequilibrium.     

A magnetic fabric study of Late Whitcliffian (U. Silurian) siltstones from the Welsh Borderland

The uppermost Whitcliffian strata of the Welsh Borderlands record the final phase of marine sedimentation in the Silurian basin and shelf environments. They give way transitionally to the succeeding non-marine Lower Old Red Sandstone. As a contribution to the understanding of the change from marine to continental facies, the magnetic fabric method was used to obtain palaeocurrent data for the uppermost Whitcliffian. The results confirm that the uppermost Whitcliffian palaeocurrent pattern is essentially “Silurian” in character and does not foreshadow the deltaic and littoral patterns of sediment distribution observed in the basal Old Red Sandstone.     

Late Pleistocene and Holocene coastal palaeoeconomies: A reconsideration of the molluscan evidence from northern Spain

The worldwide increase in shell midden deposits on coastlines during the Holocene has been variously explained as the result of human population growth, economic intensification, changes in the visibility of midden deposits with changes in sea level, or climatic and environmental changes. Since coastlines are relatively unstable in geological and ecological terms, and since many archaeological sequences span periods of major climatic change, a critical issue is the ability to disentangle palaeoenvironmental from cultural and anthropogenic effects. We draw on a case study from the cave sequences of northern Spain to illustrate the problems and possibilities of palaeoeconomic and palaeoenvironmental interpretation, using studies of palaeogeographical context and analysis of abundance, taxonomic representation, ecological tolerances, size, growth structures, and other physical and chemical characteristics of the molluscs themselves. We demonstrate that the dominant, but by no means exclusive, factor in archaeologically visible long‐term changes in shell‐gathering behavior is environmental change rather than cultural change. © 2003 Wiley Periodicals, Inc.     

An interpretation of some magnetic data off the west coast of Ireland

A total field magnetic anomaly contour map of the continental margin west of Ireland is described by reference to geological structure previously established by seismic reflection profiling. The western Irish Mainland Shelf, Porcupine Seabight Trough and Porcupine Ridge were previously defined as major north-south elements in the structure of the margin. Each is readily distinguished on the magnetic anomaly contour map. To the north these features terminate against, or merge with, the east-west Slyne Ridge. A pronounced change in the magnetic anomaly pattern at about 53°N suggests that the southern limit of this Ridge coincides with a major geological discontinuity extending from near the coast of Ireland to the continental slope, some 320 km to the west. The magnetic anomaly contour map gives general support to the idea that the Slyne Ridge and Porcupine Ridge represent submerged blocks of marginal continental crust, and that the Porcupine Seabight Trough is founded upon crust significantly different in character.     

Geology of the Chiltern Chalk aquifer,southern England

The unique geological history which resulted in the evolution of the Chiltern Hills to the north of London, The United Kingdom, created the underlying foundations for everything that we see there on the surface today. The roots of the Chiltern Hills lie in their Chalk foundations. To understand the details of the way the chalk acts as an aquifer it is important to understand first the origins of the chalk sediment and how the subsequent geological history of the region has impacted on the rocks preserved today.