John H. Roberts

Stratigraphic imprint of the Late Palaeozoic Ice Age in eastern Australia: a record of alternating glacial and nonglacial climate regime

Stratigraphic and sedimentological data from New South Wales and Queensland, eastern Australia, indicate that the Late Palaeozoic Ice Age comprised at least eight discrete glacial intervals (each 1–8 Ma in duration, here termed ‘glaciations’), separated by nonglacial intervals of comparable duration. These events spanned an interval from mid-Carboniferous (c. 327 Ma) to the early Late Permian (c. 260 Ma), and illustrate a pattern of increasing climatic austerity and increasingly widespread glacial ice from initial onset until an acme in the late Early Permian, followed by an opposite trend towards the final demise of glaciation in the Late Permian. The alternating glacial–nonglacial motif suggests that the Late Palaeozoic Ice Age was considerably more dynamic than previously thought. These patterns are remarkably consistent with recent interpretations of palaeofloral change, eustatic sea-level fluctuations and CO2–climate–glaciation relationships for this interval of time. The detailed record of alternating glacial and nonglacial climate mode disclosed herein may facilitate more closely resolved evaluations of stratigraphic records elsewhere, notably in far-field, ice-distal, northern hemisphere successions.

Brand Equity, Consumer Learning and Choice

The aim of this paper is to explore the links between brand equity, consumer learning and consumer choice processes in general and considering two recent trends in the market place: store brands and the Internet. We first review the advances that have occurred in brand equity research in marketing in the past decade, with particular emphasis on integrating the separate streams of research emanating from cognitive psychology and information economics. Brand equity has generally been defined as the incremental utility with which a brand endows a product, compared to its non-branded counterpart. We amplify this definition: we propose that brand equity be the incremental effect of the brand on all aspects of the consumers evaluation and choice process. We propose an agenda of research based on this amplified definition.

The effect of network structure in industrial diffusion processes

Abstract The development and diffusion of innovations involves groups of organizations with many different roles, who interact with each other (suppliers, adopters, third parties, etc.). This paper examines the nature of the communication networks that exist between adopting organizations, and from third parties and suppliers to adopters. Quantitative models of diffusion often assume that information about innovations flows along pre-existing links, that this information flows from adopters to non-adopters directly, and that there is perfect mixing in the population (i.e. every actor has an equal chance of communicating with every other actor). These are strong assumptions which should be subject to testing. We investigate the impact of differing network topologies of communications and alternative models of social contagion on observed adoption patterns. Network topologies are also extended beyond the focal industry to include suppliers, consultants and other customers. We use a simulation model to test the effect of departures from traditional assumptions on the diffusion pattern and undertake an empirical field study to examine the prevalence of those departures in one specific industry. Our simulation findings suggest that network structure can have a substantial effect on the manner in which innovations diffuse, while innovation-specific communication links, and communication through third parties does not change the shape of the penetration trajectory as much as it alters the places in the process where salesforce effort can offer the most leverage. The empirical study shows strong evidence of imperfect mixing, that both pre-existing and innovation-specific communication links are used, and that communication through third parties may be as important to the diffusion process as direct links from adopters to potential adopters.

Developing New Rules for New Markets

This article examines emerging technologies and the markets that they create, reviewing ideas about how new rules might be developed for successful participation in them. The need to examine new markets is being driven by the convergence of information technology and telecommunications, increased channel turbulence caused by the Internet, the embodiment of information technology in new products, globalization, and the increasing concentration and interdependence of industries. New rules to succeed in these markets depend on (1) an understanding of the market and (2) an ability to take that understanding and exploit it into profitable, customer-focused action. This article looks at market calibration including the development of new stimuli, measures, and models. It then takes the results of that calibration to show how firms in the new millennium can focus marketing action not only on a welltargeted marketing mix that has historically been the focus of marketing in the 1900s but by developing, maintaining, and maximizing their installed customer base.

SHRIMP zircon dating of the Permian System of eastern Australia

SHRIMP zircon dates from Permian ignimbrites and tuffs associated with fossiliferous strata within the Sydney‐Bowen Basin and New England Orogen are used to establish a time scale for the Permian System in eastern Australia. For the first time this enables direct correlation of the eastern Australian Lower Permian succession with similarly measured ages in the Permian type sections in the Russian Urals; new SHRIMP ages from tuffs within the Russian Lower Permian succession are being published elsewhere. An additional tie point with the Russian Kazanian Stage is achieved by means of a SHRIMP date in Australia constrained by foraminifers of the Pseudonodosaria borealis Zone. Almost all the other Permian biota in eastern Australia are Gondwanan; they provide the basis for regional biostratigraphic correlation, but cannot be used to correlate with the type Russian Permian. Integration of the numerical time and biostratigraphic scales indicates diachronous relationships between formations within both the Sydne...

Depositional and tectonic history of the southern New England Orogen

The southern part of the New England Orogen in the Hunter‐Myall region of NSW consists of the southeasterly extremity of the Tamworth Belt, a region of Devonian‐Carboniferous shelfal deposition between a volcanic arc in the west and a deep water accretionary wedge in the east. These depositional elements, which may have been separated from the Australian continent during the Devonian‐Middle Carboniferous, were deformed during the Permian and Triassic by up to four folding events separated by episodes of granitoid emplacement. Depositional patterns were influenced by five major cycles of sea level changes between the Late Devonian and Permian, an influx of volcanic detritus from an arc which changed in composition from andesitic in the Devonian, through dacitic in the Early Carboniferous to mainly rhyolitic in the Late Carboniferous, and in the Early Carboniferous by penecontemporaneous faulting within the shelf. The overall Carboniferous pattern of deposition was regressive. Rapid southerly movement of th...

SHRIMP zircon age control of Gondwanan sequences in Late Carboniferous and Early Permian Australia

Abstract Australia during the Late Carboniferous formed part of the Gondwana supercontinent and was close to the South Pole. Resulting continental glacigene deposits and cold water marine sequences in the Southern New England Orogen cannot be correlated biostratigraphically with Late Carboniferous successions in the northern hemisphere because they contain a low diversity biota endemic to Gondwana. Magnetostratigraphic correlation via the Permian-Carboniferous reversed magnetic superchron is presently uncertain. Sensitive high-resolution ion microprobe (SHRIMP) zircon dating of volcanics horizons in the sedimentary sequence of the Southern New England Orogen is now establishing relationships between the Gondwanan faunas and warm-climate European equivalents. In Continental sediments, correlation of the major Gondwanan glaciation of Late Carboniferous Australia is revised from Stephanian to early Namurian-Westphalian in age, a timing that matches that of the Hoyada Verde glaciation in Argentina. A major hiatus of > 15 Ma between Carboniferous rocks of the Southern New England Orogen and Permian rocks of the Sydney Basin of eastern Australia probably reflects the first deformational movements within the accretionary prism of the orogen. Nothorhacopteris, traditionally a Late Carboniferous indicator in Australia, now ranges from late Viséan to Westphalian, and an ‘enriched’ assemblage, previously correlated with the top of the Nothorhacopteris flora, is confined to the late Viséan to early Namurian. Palynofloras assigned to the Spelaeotriletes ybertii/Diatomozonotriletes birkheadensis Zones (Namurian-early Westphalian), are now confined to the Namurian, and a mid to late Westphalian age is indicated for a more diverse palynoflora identified as uppermost D. birkheadensis Zone (? = Asperispora reticulatispinosus Zone). In the cold climate marine sequence, the Levipustula levis brachiopod Zone appears to be confined to the early Namurian, and so partly corresponds in age to the continental glaciation.

Studying consideration in the consumer decision process: Progress and challenges

Abstract The study of consideration has been attracting increasing attention over the last five years (see Shocker et al., 1991 for a review). Academic interest has been piqued by realization of the fact that we are achieving a good understanding of the brand evaluation and brand choice processes, given consideration, but less of an understanding of what drives brand consideration. From an academic perspective this lack of knowledge is troubling. From a practical perspective, managers have become increasingly concerned that in crowded markets their brands may not even gain entry into the consideration set. This is a practical problem if the factors that determine consideration are different from those that affect choice. Gensch (1987) suggests that different attributes may be used at multiple stages of choice. Nedungadi (1990) provides strong evidence that brand evaluation, a major determinant of choice, may not play the primary role during memory-based brand recall and consideration. Roberts and Lattin (1991) suggest that the functional form relating preferences to choice will be different once we take account of consideration sets.

Carboniferous to Lower Permian stratigraphy of the southern Tamworth Belt, southern New England Orogen, Australia: Boundary sequences of the Werrie and Rouchel blocks

Carboniferous to Lower Permian successions along the western border of the Tamworth Belt between Wallabadah and Muswellbrook were remapped to clarify the stratigraphy and establish a boundary between the Werrie and Rouchel blocks. The boundary, located at the Waverley Fault, separates Carboniferous sequences containing different formations and volcanic members. SHRIMP AS3 dating of volcanic members indicates that successions within the Rouchel and Gresford blocks were deposited, uplifted and eroded at different times. The lacustrine Woodton Formation in the Werrie block, previously considered Carboniferous, is earliest Permian (Asselian) from palaeobotanical and SHRIMP AS3 evidence. Stratigraphic and palaeoenvironmental differences between the Werrie and Rouchel blocks suggest that they were not directly juxtaposed during the greater part of the Carboniferous, supporting palaeomagnetic evidence that blocks within the Tamworth Belt are allochthonous. Superposition of the western extremity of the Waverley Fault by Lower Permian (Sakmarian) formations and intrusion of folded and faulted Devonian to Lower Permian successions by the Barrington Tops Granodiorite (ca 280 Ma) indicate that the Werrie, Rouchel and Gresford blocks were subjected to tectonism before the Late Permian Hunter – Bowen Orogeny.

The numerical age of the Devonian-Carboniferous boundary

The SHRIMP ion microprobe has been used to date zircons in a 1 cm thick bentonite located in the Hasselbachtal auxiliary global stratotype section through the Devonian-Carboniferous boundary in Germany, and a tuff located at a similar biostratigraphic level in Australia. Multiple replicate analyses have yielded indistinguishable ages, and indicate 353.2±4.0 Ma (2σ) as the age of the boundary. Obtaining an age for the boundary in the German reference section depended on the ability of SHRIMP to date a small sample and to target small areas of structurally complex zircons. Future refinements of the age of this boundary may depend on re-analysis of this uniquely placed bentonite, and this highlights the value of defining biostratigraphic stratotypes in the vicinity of known dateable horizons.