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Carbonate platform systems: components and interactions - an introduction

ENZO INSALACO 1, PETER SKELTON 2 & TIM J. PALMER 3 1 TotalFinaElfExploration UK PLC, Geoscience Research Centre, 30 Buckingham Gate, London, SW1E 6NN, UK 2 Department of Earth Sciences, Open University, Milton Keynes MK7 6AA, UK 3 Institute of Geography and Earth Sciences, University of Wales Aberystwyth, Aberystwyth, Ceredigion SY23 3BD, UK

Carbonate platforms are open systems with analyse their interactions, detect significant natural boundaries in space and time. Across differences as well as similarities between them, their spatial boundaries there are fluxes of and so explore the possible causes and effects of energy (e.g. light, chemical energy in com- changes through time. In short, our quest is for pounds, and kinetic energy in currents and mass the reality of variety, not imagined unity. flows) and matter (e.g. nutrients, dissolved gases The studies presented here concentrate on such as CO2, and sediment - especially, of shallow- platform systems, with an occa- course, ). Internally, these fluxes are sional nod towards fossil mudmounds of deeper regulated by myriads of interactions and feed- water origin, largely because these are the most backs (Masse 1995), and the residue is consigned accessible and best-understood examples of sub- to the geological record. The most distinctive stantial carbonate bodies. Nevertheless, we aspect of carbonate platforms is the predomi- should also note in passing the existence of sig- nant role of organisms in producing, processing nificant tracts of deep-water mounds today, and/or trapping carbonate sediment, even in around the North Atlantic (Mortensen et al. examples. 1995), for example. Ongoing work on these Because of evolutionary changes in this strong should provide interesting comparisons with biotic input, it is harder to generalize about their shallow-water counterparts, especially with carbonate platforms than about most other sedi- respect to the effects on fabrics and of their mentary systems. Evolution has altered both the very different circumstances of development. constructive and destructive effects of platform- The geological outcomes of platform develop- dwelling organisms on carbonate fabrics, with ment depend upon a hierarchy of interactions. profound consequences for facies development. At the lowest level are those that structure com- Moreover, changing patterns in the provision of munities, often involving taphonomic feed- accommodation space (e.g. between greenhouse backs. Over larger scales of time and space, and icehouse climatic regimes) have also left , eustacy, climate and oceanographic their stamp on facies geometries, in turn feeding factors set their own imprints on the physiogra- back to the evolution of the platform biotas. phy and facies anatomy of platforms, including Hence simplistic analogies between modern and the determination of their beginnings and ends - ancient platforms may give rise to misleading the temporal boundaries of the platform interpretations of what the latter were like and systems. We have accordingly arranged the thir- how they formed. Although a number of carbon- teen papers presented in this volume in two ate platform and specialists have warned of parts, to reflect this hierarchical scaling. Part 1 the dangers of such misplaced uniformitarianism concerns community level aspects, from organ- (e.g. Braithwaite 1973; Gili et al. 1995; Wood isms and sediment production, to growth fabrics. 1999), it remains depressingly commonplace in Themes include: the literature on ancient carbonate platforms. (a) the ecology and palaeoecology of benthic The endless quest in the literature for an all- biotas, particularly factors influencing purpose definition of 'reefs' in the fossil record growth fabric genesis; is symptomatic of this delusion. Like the Holy (b) processes and rates of skeletal growth, bio- Grail of Medieval legend, the object of the erosion and sediment production; and search remains cloaked in the vagueness of (c) taphonomic and diagenetic influences. myth. The aim of this volume is more pragmatic - to present case studies that describe the com- Part 2 concerns larger scale aspects, from influ- ponents of some ancient and modern examples, ences on the growth and demise of individual

From: INSALACO,E., SKELTON,P. W. & PALMER,T. J. (eds) 2000. Carbonate Platform Systems: components and interactions. Geological Society, London, Special Publications, 178,1-8. 0305-8719/00/$15.00 9The Geological Society of London 2000. Downloaded from http://sp.lyellcollection.org/ by guest on September 24, 2021

2 ENZO INSALACO, PETER SKELTON & TIM PALMER platforms, to global patterns of change. Themes conceptual dynamic model that integrates these here include: processes. When viewed in this fashion it is clear that changes in one component can result in (a) factors influencing the establishment and positive or negative feedbacks from others. demise of carbonate platform systems; The rates at which these component processes (b) the of carbonate plat- operate, over very short temporal scales forms and its bearing on the development of (seasons to decades), and their effects and link- biogenic lithosomes within them; and ages with other factors are variously examined (c) global estimates of carbonate production by in this first part of the book. Their geological various carbonate platform systems through implications and the degree to which they can be the Phanerozoic. inferred from the geological record are also con- sidered. There is a huge literature on reef Part 1: Community level processes and science spread across the biological, palaeonto- logical and sedimentological domains, and a products comprehensive review is beyond the scope of Growth fabrics (sensu Insalaco 1998) emerge this book. Recent reviews of the general subject from tightly integrated systems of abiotic and area are given in Fagerstrom (1987), Birkeland biotic components that display a variety of (1997) and Wood (1999). organism - environment feedbacks. Processes These themes are discussed with respect to that have a bearing on what type of fabric is pre- (Riegl & Piller), coralline algae (Nebel- served include: recruitment, growth and repro- sick & Bassi), cyanobacteria (Wright & Alter- duction of skeletalized organisms; bioerosion: mann), rudist bivalves (Steuber, Gili & Skelton), secondary encrustation; sediment autoproduc- polychaetes (Naylor & Viles) and macroborers tion by mechanical and biological erosion in situ: (Perry & Bertling), and with reference to differ- sediment import (both siliciclastic and carbon- ent time periods from the Precambrian to the ate) and export (including dissolution); and present day. The different temporal scales of early marine cementation. Figure 1 presents a processes are also addressed, ranging from those

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Fig. 1. Conceptual diagram illustrating the biological and sedimentological components and interactions involved in growth fabric production by shelly benthos on carbonate platforms. (Ac) sediment accumulation rate; (Au) Autoproduction (mechanical and biological erosion); (Bi) bioerosion; (En) encrustation; (Ex) sediment export (including dissolution); (Gr) skeletal growth rate; (Im) sediment import; (Mo) mortality; (Re) recruitment; (SAZ) sedimentologically active zone; (T n) successive time slices; (TAZ) taphonomically active zone. Downloaded from http://sp.lyellcollection.org/ by guest on September 24, 2021

CARBONATE PLATFORM SYSTEMS - AN INTRODUCTION 3

operating within the lifetime of an individual system of feedbacks between shell growth, (Naylor & Viles, Steuber, Riegl & PiUer) to the packing density and current activity, which time involved in the formation of entire biogenic yielded a highly efficient, if ephemeral, kind of lithosomes (Gili & Skelton). The studies also carbonate factory in propitious conditions. concern a variety of depositional contexts In modern platform environments, organisms (ramps, shelves, mixed carbonate-siliciclastic also play a major role in skeletal breakdown systems, and both tropical and temperate (Bromley 1994). Such bioerosional processes regimes). are considered in the paper by Perry & Bertling, The first two papers look at the role of skeletal who have assessed the impact of boring by accretion (either by sand-trapping or carbonate macroscopic organisms on and Ceno- shell growth) and environmental consequences. zoic coral reefs. Macroboring of coral reefs has Though set in a siliciclastic context, the study varied significantly through time, with the of Naylor & Viles illustrates the environmental modern intensity and producer composition a feedbacks of bioconstructions, with reference to relatively recent phenomenon. Given the impact Sabellaria alveolata (Linn6), a sedentary poly- of bioerosion on framework morphology, com- chaete that builds significant, but poorly docu- munity composition and sediment production mented, wave-resistant reefs from sand particles. today, Neogene reef systems make poor ana- Reefs can form quite rapidly in temperate logues for understanding the structure and with a large, continuous supply of sand-grade dynamics of older examples. Sponges (dominant sediment and turbulent water in the lower eulit- now) appear to have played a subordinate role total zone. They have three main environmental in Mesozoic coral-dominated buildups. Worms effects. First, they increase topographical vari- and barnacles dominated in the early Mesozoic ation in the lower eulittoral zone, such as enhanc- ( and early Jurassic), with a progressive ing pool forms, thereby increasing the amount of increase in bivalve borers through the Jurassic. sheltered habitat for other marine fauna. Sec- Macroborers may have radiated to colonize new ondly, they increase surface roughness, which ecological niches during the early stages of coral possibly reduces wave energy as dissipates reef diversification. The trend was nonetheless more quickly over rougher surfaces ('bioprotec- influenced by other biotic changes in the marine tion'). Thirdly, the reefs appear to protect the realm, especially switches in nutrient status and underlying from direct wave attack the origins or diversification of reef grazers. and abrasion by physically covering the surface Besides the constructive and destructive pro- and by storing sediment that might otherwise be cesses discussed above, also takes a available to abrade the shore. hand in fabric development. Wright & Alter- In a more classically carbonate context, mann have looked at growth fabric taphonomy Steuber has deployed geochemical scle- from a diagenetic angle in Late Archaean age rochronology to measure skeletal growth rates and ooids of the Ghaap Group, of Upper rudist bivalves, in order to South Africa. This case study illustrates the evaluate their implications for carbonate pro- importance of microbial communities as duction and organism-environment feedbacks. process-drivers for carbonate precipitation (see Estimated values of annual CaCO3 production also Webb 1996). Detailed microfabric analysis in dense congregations range from 4.6 to 28.5 kg illustrates the close relationship between m -e - comparable to those reported from organic decay processes, carbonate mineralogy modern coral reefs. Study of a rudist-bearing and fabric development. It appears that the out- sedimentary sequence revealed a decrease both comes were in part controlled by diagenesis in shell size and carbonate production of a single under reducing conditions. Anoxic microbial species in a transect from turbulent outer plat- decay, by modifying ambient water chemistry, form, to lagoonal inner platform deposits. set the context for carbonate precipitation. Accumulating bioclastic sediment and fouling Moreover, the degree of organic degradation by faeces and pseudofaeces may have inhibited was a significant control on the mineralogy (e.g. growth and excluded many other taxa in the dolomite formation). Hence, even from restricted settings where current-flushing was Archaean times, carbonate platform develop- infrequent, while nutrient flux and frequent ment bore the imprint of biotic activity. flushing allowed optimal growth on the outer The influence of topographical context is con- platform. The rapid vertical growth of the sidered next, in the paper by Riegl & Piller, who would have mitigated against the effects discuss Recent coral carpets and reefs in the of fouling, but only where sedimentary accumu- northern Red Sea and the gulfs of Suez and lation was itself sufficient to maintain shell stab- Aqaba. They show the dependence of growth ility. Thus there appears to have been a complex fabric types on a combination of sea-floor Downloaded from http://sp.lyellcollection.org/ by guest on September 24, 2021

4 ENZO INSALACO, PETER SKELTON & TIM PALMER topography, hydrodynamic aspect and the for subsequent recruitment; and secondly, bio- ecology of constituent coral species. Reef erosion of shells fuelled the in situ formation of frameworks show a clear ecological zonation bioclastic sediment, leading to the embedding along depth and hydrodynamic exposure gradi- and consolidation of congregations. Thereafter, ents. Coral carpets, by contrast, build a frame- an inferred correlation between rudist density work lacking a distinct internal zonation since and sediment destabilization at the benthic they grow only in areas without pronounced boundary layer is postulated to have affected gradients. The initiation of the differing frame- rudist recruitment. Thus, successful rudist larval work types was governed by bottom topogra- settlement declined with increasing numerical phy. They differ, moreover, in their patterns of density of individuals - a crucial negative feed- sediment retention - the carpet tends to retain back mechanism. The rudist congregations its bioclastic production, while the reef exports could then have been maintained at about the it. Synchronously with framework growth, the same density through time by this stabilizing environment itself is modified, which in turn process, until shoaling and/or swamping by modifies the coral communities. Thus an renewed allochthonous influxes terminated environment-organism-environment feedback them. loop exists. Of this set of seven papers, only one (Riegl & To discover what kinds of formative processes Piller) concerns itself directly with growth fabric and conditions can be interpreted from the fossil development in modern coral reefs. This may record, Nebelsick & Bassi have analysed growth seem surprising in a book about interactions and fabric variation in coralline algal-dominated feedbacks in carbonate platform ecosystems, of Lower Oligocene shelf carbonates from north- which coral reefs are probably the most widely ern Slovenia. They demonstrate the importance investigated examples. Yet the concerns of the of assemblage diversity, growth-forms and other papers - shell growth and carbonate pro- taphonomy in controlling the type of fabric duction, bioerosion, taphonomy (including alia- preservation. A wide range of taphonomic fea- genesis) and factors controlling recruitment and tures, including disarticulation, encrustation, mortality - are relevant across the entire spec- fragmentation and abrasion, can be observed. It trum of carbonate platform ecosystems, includ- is noted that the taphonomy of is ing modern coral reefs. This point brings us back highly dependent on initial growth-form and to consideration of the dynamic model proposed specific environment. The determination of in Fig. 1: the very diversity of the examples dis- diversity is dependent on taxonomic identifi- cussed here illustrates the chaotic tendency of cation, necessarily based only on preserved diag- such a complex system to yield contrasting nostic characters. Uncertainties can thus arise results according to differing initial conditions, through conflicts between palaeontological and both biotic and environmental. botanical systematics. Growth-form determi- nation in thin section is influenced by orien- Part 2: Larger scale aspects tation and sectioning affects. Despite such problems, it is suggested that these aspects of Beyond community interactions and local limestone fabrics, when carefully analysed, can taphonomic feedbacks, a host of larger-scale form a sound basis for microfacies differentia- and/or longer-term factors modulate the tion, and hence palaeoenvironmental interpre- dynamic relationship between biogenic growth tation. fabrics and associated facies, and ultimately The final paper in this part of the volume, by control the establishment and demise of the Gill & Skelton, examines the feedbacks that platforms themselves. A serious hindrance to appear to have regulated the development of understanding these aspects of platform elevator rudist lithosomes in the Upper Cre- development is the gulf between ecological and taceous of the southern Central Pyrenees. This geological scales of observation. We know all study complements that of Steuber, viewing too little about the long-term geological reper- these distinctive biosedimentary systems in a cussions of short temporal scale environmental broader perspective in order to discern the events, and how to recognize their geological factors involved in their initiation, consolidation signatures. The scaling issue is addressed by and termination. Initiation was associated with Glynn, who looks at the effects of episodic E1 pauses in allochthonous sediment influx, them- Nifio-Southern Oscillation (ENSO) events on selves linked with minor increments of systems. These are effectively geolog- accommodation space. Two positive feedback ically instantaneous events, which may never- loops to establishment are apparent: first, theless have long term consequences for pioneer settlers provided more hard substrates evolution and extinction, and Glynn asks how Downloaded from http://sp.lyellcollection.org/ by guest on September 24, 2021

CARBONATE PLATFORM SYSTEMS - AN INTRODUCTION 5

such short-lived ecological impacts may be paper on the role of antecedent topogra- recognized in the geological record. This paper phy by Purdy (1974), and the theme is pursued thus effectively bridges the artificial gap here by Gisehler & Lomanflo, in a paper on the between the two parts of the volume. late Quaternary development of the reef Extreme environmental conditions related to tract. They find that differences in physiography ENSO activity are (1) high sea surface tempera- and facies between the various reefs relate to a tures (SSTs) and low nutrient avail- combination of antecedent topography, due to ability during E1 Nifio events, and (2) low SSTs differential and latitudinal variation and high nutrient availability during La Nifia in karstification, and hydrodynamic aspect. events. Extreme ENSO events (e.g. 1982-1983 House et al., consider events over a longer and 1997-1998) stressed eastern tropical Pacific time-span - the comings and goings of a pro- reef-building corals, with severe mortality pro- grading series of carbonate platforms in the moted by 'bleaching' during prolonged sea southern Timan and Pechora region of northern warming, and restoration inhibited by plankton European Russia during late (Frasn- blooms and overgrowth by benthic algae during ian) times. With the benefit of recent refine- periods of elevated nutrient concentrations. ments in correlation based on conodonts and Recruitment of corals has been nil to slow in ammonoids, they distinguish globally effective many disturbed areas. Intense external and influences (especially eustacy) from regional internal bioerosion by echinoids and endolithic effects. Episodes of reef development in the bivalves, respectively, has already occurred on region co-incided with transgressive phases, reefs affected by the 1982-1983 El Nifio event, some evidently eustatic, but they appear to have and reef frameworks in the Gal~ipagos Islands ended in shallowing events, unlike many that had been established for between 1000 and examples in western Europe where termination 5000 years have been reduced to cobbles and involved eutrophication and drowning. More- sand. The depauperate coral fauna and meagre over, reef developments continued into the late reef development in the eastern tropical Pacific Frasnian, whilst in other European regions they could thus be due largely to the severe and mostly ended earlier in the Frasnian. The global episodic conditions resulting from ENSO per- incidence of anoxic facies is a striking feature, turbations and subsequent low coral recruitment postulated to reflect the periodic flooding of and intense bioerosion, which limits reef sub- cold, nutrient-rich waters over epicontinental strates. But how may such events be recognized areas in connection with systems in the geological record? Possibilities proposed associated with the distinctive climatic regime of by Glynn include: the time. This substantial study illustrates the vital importance of detailed stratigraphical (a) -related oxygen isotope signa- analysis for any attempt to make sense of global tures, versus regional controls on the development of (b) skeletal stress bands and growth disconti- ancient carbonate platforms. nuities, St~ssel & Bernoulli focus more closely on the (c) increases in coral debris in beach storm internal sedimentary dynamics of carbonate deposits, platform development, in their study of the (d) increase in coral clastics resulting from Upper Cretaceous succession of the Maiella intensified bioerosion, and Platform in the central Apennines, Italy. Like (e) increased preservation of bioeroded skele- Steuber, and Gili & Skelton, they too note the tal material. prodigious bioclastic productivity of rudist- This timely study shows that taphonomy dominated associations, particularly in the outer offers one key to bridging the gap between short platform zone (see also Carannante et al. 1993, temporal scale interactions and longer-term 1997, 1999; Gili et al. 1995; Ruberti 1997). This consequences. It is an area that still has much production regularly outpaced the provision of potential to offer (see also Scoffin 1992). accommodation space, resulting in redistri- The next two papers consider factors involved bution of the bioclastic sediment both on and off in the establishment of platforms. The effect of platform, yielding the distinctively tabular facies topography on growth fabrics was noted earlier, geometry so typical of rudist platforms. Sheet- in the paper by Riegl & Piller. Over a longer like rudist lithosomes with individuals in life time-scale, the positive feedback of reef frame- position make up only some 20% of the strati- work growth on prominences during sea-level graphic thickness of the Maiella outer platform rise may amplify the relationship, so affecting zone, and are preferentially preserved in the the overall structure of a platform and its reef thicker sedimentary cycles indicative of rela- tracts. This relationship was explored in a classic tively larger increments of accommodation Downloaded from http://sp.lyellcollection.org/ by guest on September 24, 2021

6 ENZO INSALACO, PETER SKELTON & TIM PALMER space. The latter observation is particularly complex to allow reliable predictions, or biotic interesting, pointing to an important longer- factors represent more important controls than term taphonomic feedback to eventual facies physico-chemical parameters. The constructed architecture. In this context, another long-term curve of Phanerozoic reefal carbonate produc- feedback to the development of platform facies tion is also poorly correlated with proposed that should be mentioned is that of differential curves of global carbonate platform areas, sug- compaction (Hunt et al. 1996), a frequently over- gesting that reefs per se rarely made a significant looked factor. The three studies of rudist litho- contribution to the global carbonate budget. somes in this volume together paint a Such grand syntheses are bound to prove con- remarkably consistent picture of this distinctive troversial - as this one did at the conference - type of non-reefal biosedimentary system, which not least because of the assumptions used in the contrasts markedly with that of modern coral calculations. Whether or not the reader regards reefs, despite more than matching the latter in the present results as valid, however, they do terms of carbonate production. Once again, we serve to draw attention to the issues that need to are confronted with the contrasts - as much as be tackled if we are to arrive at a quantitative the similarities - between platform ecosystems account of the chequered and variegated history from different times and places, referred to of carbonate platforms and reefs. earlier. In the particular case of the Cretaceous, The volume closes with Schlager's global this has also been an emergent theme in the review, which covers an even broader canvas, publications of the Global Sedimentary Geology though employing a different approach. He Programme (GSGP) CRER-Working Group 4 recognizes three major kinds of benthic produc- on Cretaceous Carbonate Platforms (Schlager & tion factory for marine carbonates - tropical, Philip 1990; Sire6 et al. 1993; Philip & Skelton cool-water, and mud-mound carbonate systems

1995). - and compares data on their sedimentation The final two papers of the volume consider rates and growth potentials. An important con- patterns on a global scale, through geological sideration stressed here, in relation to all the time. In recent years, documentation of the systems, is the decrease in measured sedimen- stratigraphical distribution of Phanerozoic tation rates according to the time span of obser- carbonate platforms has become sufficiently vation. The importance of normalizing for time comprehensive to allow broad semi-quantitative span when making comparisons cannot there- reviews of their history to be attempted. Der- fore be over-emphasized. 'Growth potential' is court et al. (1993) published a widely referred-to estimated from maximum observed rates of series of palaeogeographical maps showing plat- aggradation for each system. Highest rates form development during 14 selected time inter- overall are shown by the tropical system. vals from the late Murgabian (Permian) to the Although values for the cool-water system can Tortonian (Tertiary). More recently, Kiessling et match these for short time spans (up to 200 000 al. (1999) have assembled a 'comprehensive years), they fall back more markedly for time database on Phanerozoic reefs'. Here, these spans of over 1 Ma. Reworking and local trap- same authors use their database to calculate ping of the frequently more mobile cool-water relative carbonate production rates by reefs carbonates is regarded as probably responsible through the Phanerozoic, using certain assump- for their high short-term values. The mud- tions concerning, for example, inferred poten- mound system, surprisingly, shows rates of tials for debris production and export, and aggradation that rival those of the tropical progressive loss of record through time. Four system, though since they export considerably maxima for gross production are noted less sediment than the latter, their gross produc- (Wenlock/Ludlow, Givetian/Frasnian, late tion rate is less. Again, the assumptions involved Jurassic and Neogene). Of these, the calculated in such a broad comparison lay it open to con- Givetian/Frasnian peak is the highest, matching troversial discussion. A question that particu- the large numbers and extents of platform larly needs to be addressed is the extent to which margin reef systems known from that interval - Schlager's tripartite classification of carbonate one major example of which was described factories, based essentially on modern carbon- earlier in this volume by House et al. Kiessling ate sediments, can be applied legitimately to the et al. compare their plot with inferred variations past. Carannante et aL (1997,1999), for example, in such extrinsic factors as eustatic sea-level, have cogently argued that 'foramol-type' Upper crust production, atmospheric CO2 levels, Cretaceous rudist , though geograph- palaeoclimate and nutrient availability, but find ically tropical, were more like 'cool-water' car- few correlations. They conclude that either the bonates in terms of their sedimentological controls on reefal carbonate production are too attributes. Downloaded from http://sp.lyellcollection.org/ by guest on September 24, 2021

CARBONATE PLATFORM SYSTEMS - AN INTRODUCTION 7

Prospect carbonate production and redistribution varied along with changing patterns in the provision of As with any thriving area of scientific enquiry, accommodation space? Allied with such ques- the studies here beg as many questions as they tions is the crucial issue, raised several times in offer answers. They invoke models that require the book, of the temporal scaling of rates - the further testing and assumptions that may be non-linear translation of short-term effects (e.g. open to debate, and so sustain the need for more sedimentation and disturbance) into long-term primary data. Hence, in addition to what they outcomes (platform sequences). These and report, they also serve to identify where new other matters concerning the dynamics of initiatives might be directed. Each highlights carbonate platform systems have been tackled in particular needs, but two general issues are a preliminary fashion in this book. The many worth commenting upon in conclusion. questions that remain should help to set the As noted at the beginning of this introduction, agenda for future work in this rapidly growing differing biotic and other environmental inputs field of study. to the growth of carbonate platforms have led to some significant differences in their forms and distributions. The variability of the examples References discussed in this book illustrate the point, so B1RKELAND, C. (ed.) 1997. Life and Death of Coral reinforcing the need to generate synthetic inter- Reefs. Chapman & Hall, New York. pretative models of ancient platform systems BRAITHWAITE, C. 1973. Reefs: just a problem of from primary observational data. Simplistic semantics? American Association of Petroleum imposition of generalized models based on Geologists Bulletin, 57, 1100-1116. (certain) modern reef systems, for example, can BROMLEY, R. G. 1994. The palaeoecology of bioero- be misleading. At issue is the appropriate level sion. In: DONOVAN,S. K. (ed.) The palaeobiology at which to apply uniformitarian analogy. At the of trace fossils. John Wiley, Chichester, 134-154. level of simple physical, chemical and to some CARANNANTE, G., RUBERTI, D. & SIMONE, L. 1993. Rudists and related sediments in late Cretaceous extent biological relationships, it is a good open shelf settings. A case history from Matese friend. At the level of whole, complex deposi- area (central southern Apennines, Italy). Gior- tional systems, however, it can deceive. nale di Geologia, (3a), 55, 21-36. A second general point is that at all hierarchi- CARANNANTE, G., GRAZIANO, R., RUBERTI, D. & cal levels, from the genesis of growth fabrics to SIMONE, L. 1997. Upper Cretaceous temperate- global patterns of carbonate platform develop- type open shelves from northern (Sardinia) and ment, the rates of processes are seen to be as southern (Apennines-Apulia) Mesozoic Tethyan important as their nature in moulding the margins. In: JAMES,N. P. & CLARKE,J. A. D. (eds) variety of outcomes in the record. In many Cool-water carbonates. Society of Economic Pale- ontologists and Mineralogists, Tulsa, Oklahoma, instances we have a fair idea of the main pro- Special Publication, 56, 309-325. cesses concerned, but our knowledge of their CARANNANTE, G., GRAZIANO, R., PAPPONE, G., rates is often based on limited data. Hence there RUBERTI, D. & SIMONE, L. 1999. Depositional is a need for more quantitative estimation of system and response to oscillations of the rates, so that conceptual models (like Fig. 1) can Senonian rudist-bearing carbonate shelves. be converted to predictive numerical models Examples from central Mediterranean areas. amenable to rigorous testing. For example, how Facies, 40, 1-24. have relative rates of skeletal carbonate produc- DERCOURT, J., RIcou, L. E. • VRIELYNCK, B. (eds) tion and sediment autoproduction through bio- 1993. Atlas Tethys palaeoenvironmental maps. Gauthier-Villars, Paris, 1-307. erosion varied in time and space? And how have FAGERSTROM, J. A. 1987. The evolution of reef com- these variations, in tandem with diagenetic influ- munities. John Wiley and Sons, New York. ences, affected the potentials of platform GILI, E., MASSE,J.-P. & SKELTON,P. W. 1995. Rudists as systems for in situ carbonate aggradation and gregarious sediment-dwellers, not reef-builders, export? At around what (short-term) rates did on Cretaceous carbonate platforms, Palaeo- given types of growth fabric accumulate, and geography, Palaeoclimatology, Palaeoecology, how long did it take for lithosomes comprised of 118, 245-267. them to form, relative to other deposits? How HUNT, D., ALLSOP,T. & SWARBRICK,R. E. 1996. Com- have the frequency and distribution of ecologi- paction as a primary control on the architecture and development of depositional sequences: con- cal perturbations such as ENSO events, hurri- ceptual framework, applications and impli- canes and - especially further back in time - cations. In: HOWELL, J. A. & AITKEN, J. F. (eds) oceanic anoxic events varied, and what (if any) High Resolution Sequence Stratigraphy: Inno- correlation do they show with the changing for- vations and Applications. Geological Society, tunes of platforms? How have relative rates of London, Special Publications, 104, 321-345. Downloaded from http://sp.lyellcollection.org/ by guest on September 24, 2021

8 ENZO INSALACO, PETER SKELTON & TIM PALMER

INSALACO, E. 1998. The descriptive nomenclature and RUBERTI, D. 1997. Facies analysis of an Upper classification of growth fabrics in fossil scleractin- Cretaceous high-energy rudist-dominated carbon- ian reefs. Sedimentary Geology, 118, 159-186. ate ramp (Matese Mountains, central-southern KIESSLIN6,W., FLt)GEL, E. & GOLONKA, J. 1999. Paleo Italy): subtidal and peritidal cycles. Sedimentary Reef Maps: Evaluation of a comprehensive Geology, 113, 81-110. database on Phanerozoic reefs. American Associ- SCHLAGER,W. & PHILIP, J. 1990. Cretaceous carbonate ation of Petroleum Geologists Bulletin, 83, platforms. In: GINSBURG, R. N. & BEAUDOIN, B. 1552-1587. (eds) Cretaceous resources, events and rhythms MASSE, J.-P. 1995. Carbonate platforms as systems. (NATO ASC. Series, 304), Kluwer, Dordrecht, GOologie MOditerrandenne, 21, 125-126. 173-195. MORTENSEN, P. B., HOVLUND, M., BRATTEGARD, T. & SCOFFIN, T. P. 1992. Taphonomy of coral reefs: a FARESTVEIT R. 1995. Deep water bioherms of the review. Coral Reefs, 11, 57-77. scleractinian coral Lophelia pertusa (L.) at 64 ~ N SIM6, J. A. T., SCOTT, R. W. & MASSE, J.-P. (eds) 1993. on the Norwegian shelf: structure and associated Cretaceous carbonate platforms. American megafauna. Sarsia, 80, 145-158. Association of Petroleum Geologists, Memoir, PHILIP, J. & SKELTON,P. W. (eds) 1995. Palaeoenviron- 56, 1-479. mental models for the benthic associations of Cre- WEBB, G. E. 1996. Was Phanerozoic reef history con- taceous carbonate platforms in the Tethyan trolled by the distribution of non-enzymatically realm. Palaeogeography, Palaeoclimatology, secreted reef carbonates (microbial carbonate Palaeoecology, 119, 1-199. and biologically induced cements)? Sedimen- PURDY, E. G. 1974. Karst-determined facies patterns tology, 43, 947-971. in British Honduras: Holocene carbonate sedi- WOOD, R. 1999. Reef Evolution. Oxford University mentation model. American Association of Press, Oxford. Petroleum Geologists Bulletin, $8, 825-855.