Late Cretaceous Deposits Research Articles

Diversity of smectite origins in Late Cretaceous sediments: example of chalks from northern france

AbstractAccording to XRD, DTA, geochemistry and electron microscopy data of a few selected samples, three categories of smectitic clay minerals occur in the Cenomanian and Turonian chalks sampled in several sections of northern France. The first one corresponds to detrital illitesmectite mixed-layers reworked from pedogenic blankets. The second category, characterized by crystalline overgrowths around detrital particles, is especially well-developed in slowly deposited sediments. The third category, located in thin marly horizons, corresponds to Cheto-montmorillonite derived from the submarine alteration of volcanic glass. Smectitic minerals having distinct origins may therefore occur at different levels of a given formation. From these examples, the smectite-rich clay sedimentation of the Late Cretaceous is tentatively explained by the combination of favourable factors induced mainly by highstand of the sea-level. The climatic conditions, the reduction of continental areas, the development of carbonate platforms and the decrease in sedimentation rates constitute the most relevant of these factors.

Facies variation, depositional setting and hydrocarbon potential of the Upper Cretaceous rocks in the United Arab Emirates

The Upper Cretaceous (Aruma Group) of the United Arab Emirates (UAE) was deposited over nearly 23 Ma. This was after a period of major erosional emergence in the Turonian. The variable thicknesses and lithofacies of the sediments of this group were controlled by regional subsidence induced by plate collision and partial subduction, eustatic sea-level fluctuations and differential sedimentation rates. The Upper Cretaceous in the southern UAE (Abu Dhabi region) consists of two major transgressive-regressive cycles involving the sediments of four formations, the Laffan, Halul, Fiqa and Simsima. In the central UAE (Dubai region) the group consists of the Laffan, Ilam, and Fiqa Formations, while in the northern UAE it consists of the Muti, Juweiza, Qahlah and Simsima Formations. The earliest Late Cretaceous sedimentation accompanied a marine transgression that probably began in the late Turonian, with the sea spreading to cover most of the UAE by Coniacian times. This marine event was marked by the deposition of basinal muds (not shales) and neritic marls. Later, during Santonian, neritic shelf carbonates were deposited. Subsequent subsidence in the early Campanian resulted in the accumulation of deep-water marls, argillaceous limestones and muds (shales). During the Maastrichtian, a widespread regression occurred, and neritic shelf bioclastic limestones and dolomites containing rudists and orbitoids were deposited on the shelf margin. Toward the centre of the basin, in the northern UAE, thicker, basinal, slope and shelf edge sediments were deposited resulting in a succession that consists mostly of marls, argillaceous limestones, cherts, conglomerates, sandstones and shales. Commercial hydrocarbons in the Upper Cretaceous are confined to the Simsima and Ilam Formations, which are the best potential exploration targets, particularly in the offshore of the northeastern Emirates in a belt parallel to the Oman Mountains. The basal part of the Upper Cretaceous is a major seal over middle Cretaceous reservoirs of the UAE.

Late Cretaceous to Early Tertiary palaeogeography of the Western Carpathians (Slovakia) and the Eastern Alps (Austria): implications from heavy mineral data

The Late Cretaceous Brezova and Myjava Groups of the Western Carpathians in Slovakia and formations of the Gosau Group of the Northern Calcareous Alps in Lower Austria comprise similar successions of alluvial/shallow marine deposits overlain by deep water hemipelagic sediments and turbidites. In both areas the heavy mineral spectra of Late Cretaceous sediments contain significant amounts of detrital chrome spinel. In the Early Tertiary the amount of garnet increases. Cluster analysis and correspondence analysis of Coniacian/Santonian and Campanian/Early Maastrichtian heavy mineral data indicate strong similarities between the Gosau deposits of the Lunz Nappe of the north-eastern part of the Northern Calcareous Alps and the Brezova Group of the Western Carpathians. Similar source areas and a similar palaeogeographical position at the northern active margin of the Adriatic/Austroalpine plate are therefore suggested for the two tectonic units.

New evidence of Permo-Triassic rifting, onshore southern Ireland, and its implications for Variscan structural inheritance

Abstract Reconnaissance apatite fission track analysis data from onshore southern Ireland are used to construct a thermal history for Late Palaeozoic rocks. The data show clear evidence of post-Variscan heating. The most significant thermal event took place during the Permo-Triassic, and resulted from not less than 1 km of regional subsidence. Late Palaeozoic rocks were again uplifted and exposed during the Early Jurassic. Significant deposition did not resume until the Late Cretaceous, and was followed by uplift and inversion emanating from the North Celtic Sea Basin. Repeated post-Variscan extension and compression of the Variscan basement must therefore have taken place, making it now difficult to differentiate bona fide Variscan deformation. However, the northern extent to both Permo-Triassic and Late Cretaceous sedimentation was probably controlled by extension along a line of major Variscan thrusts in south-central Ireland — the South Ireland Lineament.

Evidence for the multi-stage formation of the south-western Valencia Trough

A basin evolution model for the south-western Valencia Trough is established using thermal and palaeo-thermal data. Bottomhole temperature and drillstem test data from oil wells have been used to determine the geothermal gradient in the study area. A combination of well log data and X-ray diffractometry analyses carried out on rock samples from the Ibiza Marino well has allowed an estimation of the bulk thermal conductivity and heat flow density. Integrating these data with previous seafloor heat flow measurements yields a regional surface heat flow density of about 90–100 mW m −2. Vitrinite reflectance data available from the Ibiza Marino well have been used as a palaeo-thermal constraint for the proposed tectonic models. Two different modelling approaches are tested: a single rift phase model and a multi-phase formation model. The single rifting phase, which considers different eroded thicknesses, is ruled out as it does not match the observed data. A multi-stage evolution coherent with the geological and geophysical data is proposed and consists of three Mesozoic rifting events, Palaeogene compression (to which erosion of about 5 km of Late Jurassic and Cretaceous sediments is related) and a Neogene rifting event that gave rise to the present day Valencia Trough. Surface heat flow, vitrinite data and eroded thickness are successfully integrated in the proposed model.

Palaeogeography and geodynamic evolution of the Gosau Group of the Northern Calcareous Alps (Late Cretaceous, Eastern Alps, Austria)

The sedimentation of the Late Cretaceous Gosau Group of the Northern Calcareous Alps records the complex geodynamic evolution of the northern part of the Austroalpine microplate. The tectonically controlled sedimentation and facies distribution were mainly governed by the oblique subduction of the Pennic-Ligurian ocean below the Austroalpine margin. Most of the Gosau successions comprise two distinct sedimentary complexes. The Lower Gosau Subgroup (upper Turonian-Campanian) is characterized by terrestrial to shallow-marine facies associations: alluvial fan and fan delta deposits, shallow-marine sandstones and sandy limestones, and storm-influenced nearshore and shelf deposits. During the early Santonian sea-level highstand, a great part of the Northern Calcareous Alps was covered by a shallow shelf sea. Palaeotransport directions point to source areas situated both to the north and to the south of the Northern Calcareous Alps. The Upper Gosau Subgroup (upper Santonian-Eocene) comprises deep-water hemipelagic and turbiditic deposits. Rapid subsidence into bathyal to abyssal depths started diachronously from the northwest (Santonian) to the southeast (Maastrichtian) after a short phase of deformation and erosion. Abyssal deposits in the northern parts of the Northern Calcareus Alps and north-directed palaeotransport indicate a tilting of the slope towards the north. This subsidence pulse is attributed to an event of subcrustal tectonic erosion, probably triggered by the subduction of a topographic high of the South Penninic ocean. The relationships of the Gosau Group of the Austroalpine unit to Late Cretaceous deposits of the Carpathians and Southern Alps are discussed in the framework of a plate tectonic model.

Paleogeographic and paleotectonic implications of clay mineral distribution in late Jurassic-early Cretaceous sediments of the Pindos-Olonos and Beotian Basins, Greece

A new method is proposed for solving the controversial problem of the location of oceanic areas from which the Pindos and Othrys ophiolites originated. Assuming that clay fractions, quickly disseminated over large areas, may be reliable markers of erosional processes, we studied these fractions in sediments from two “external” basins (Pindos-Olonos and Beotian) located between the main carbonate platforms of the Greek Hellenids. Chronologically, two different clay associations can be distinguished in the sedimentary sequences of the basins. The lower one is dominated by illite and subregular illite-smectite mixed-layers and poor in Mg, Ni and Cr; this association is consistent with common continental sources. The upper one, appearing in late Tithonian synchroneously in both basins, consists of trioctahedral smectite (saponite type) enriched in Fe, Mg, Ni and Cr; they are considered to be derived from weathered ophiolites. Thus, the beginning of the ophiolite detrital sedimentation, accepted as being middle to late Bathonian in the basinal sequences of the Maliac or Othrys zone from Hydra or lower-middle Oxfordian in all the internal units in the Argolis Peninsula, is much younger (late Tithonian) in the external basins. Such a diachronism is not consistent with a model postulating initial ophiolite displacements within the Pindos-Olonos basin by late Jurassic time. It suggests that a platform was acting as a barrier between the site of the ophiolite first intra-oceanic deformation and the “external” basins. This barrier cannot be the Parnassus platform that kept subsiding in neritic environments until late Cretaceous inside the “external” basins; it is likely to be the Pelagonian platform, positively known to have been submerged during the Tithonian. Consequently, we conclude that there was no genetic relationships between the “external” basins (Pindos-Olonos basin in a broad sense) and the “Pindos ophiolites” of which the zone of origin is to be located on the opposite eastern “internal” side of the Pelagonian platform.

Geological settings of the metallogenic prognosis in Strandža-Sakar (Southeastern Bulgaria)

Strandža-Sakar covers the eastern part of the Srednogorie zone and is formed like a Late Cretaceous magmatic arc over geodynamic background, represented by the active margin of the Moesian Platform (Yambol-Burgas region) and by two exotic accretion blocks - the Strandža-Sakar and the East Thracia ones. The latter represent a collage system built in the period of the Late Jurassic – Early Cretaceous. The Srednogorie magmatic arc includes flysch troughs and back-arc rift basins (the Black Sea). However, the most outstanding phenomenon in metallogenic aspect is the Late Cretaceous magmatism, which has formed relatively well preserved central type volcano-intrusive structures. The Eastern Srednogorie volcano-intrusive area is distinguished for the most intensive, basic (typically basalt with wide differentiation) and highest potassium alkaline magmatism with evolution and special-temporary lateral (S-N) zonality characteristic for the mature island arcs. Subequatorial (90°-120°), oblique (30°-40°) and submeridian (170°-190°) more significant fault systems could be subdivided. The ore deposits are divided into preaccretion (exotic), accretion and postaccretion depending on the setting. Most of the preaccretion deposits, which have undergone dislocation metamorphism together with the embedding geocomplexes, are stratiforme and syngenetic. The iron-polymetal ore mineralisations with insignificant and low probability prediction assessment are more important. The accretion deposits are not numerous and are also with low probability prediction assessment. The postaccretion metallogeny is more important and significant. It includes two age groups: Late Cretaceous and Late Tertiary. The Late Cretaceous deposits are of proxymate type, connected with the volcano-intrusive centres of the magmatic arc. The ore mineralisations occur during all stages of centres' evolution: antemagmatic (Mg-scarns with magnetite), intermagmatic (iron-bearing ±V-, Ti-gabbro) and postmagmatic (porphyry-copper ±Mo, W, copper-gold-polymetal veins and scarns), etc. The above mentioned ore mineralisations are well studied and at advanced stage of exploitation. The prediction here is strongly limited. The Late Tertiary ore mineralisations have distal, telethermal character and are represented by low temperature anthimony-gold-polymetal veins and stockwerkes (?) which are poorly studied and with high perspectives. The gold-bearing alluvial placer, like the recent (Plio-Quaternary), as well as the old (Cenomanian-Turonian) formations could be referred to the perspective ones.

Exploration of the Late Cretaceous and the Oligocene Sequences Underneath the Pirital Allochthonous Block, Northern Monagas Area, Eastern Venezuela Basin: ABSTRACT

The search for reservoir rock beneath the Pirital allochthonous block began when the Mene Grande Oil Company drilled 7 exploratory wells. These penetrated the Pirital allochthonous block, but, due to mechanical problems, they did not reach their objective. At that time, the proposed exploratory model suggested a high angle reverse fault at the base of the allochthonous block which restricted the prospective section toward the north. In 1989, after drilling 11 exploratory wells along the El Furrial-El Tejero trend, a new exploratory model was proposed. The base of the Pirital block is a sub-horizontal plane and the Late Cretaceous and Oligo-Early Miocene sediments are extended northward beneath it. A well, SBC-3E, was drilled in order to test the new model and it was completed in December, 1989. It produced 6100 BOPD of 35[degrees] API and 47 MMCFD. A second well, PIC-IE, located 7.5 km toward the northwest of the SBC-3E, was drilled in order to investigate the quality of the reservoir rocks beneath the Pirital block. This well was completed in April, 1992, with a production of 4500 BOPD of 36[degrees] API and 37 MMCFD. The success of these two wells drilled north of the Pirital thrust suggest an exploratorymore » area as big as the El Furrial-El Tejero trend. However, two geological risks must be addressed, the thickness of the allochthonous block and the depth of the oil-producing strata.« less

Late Cretaceous Paleogeography, Sediment Accumulation, and Coal Distribution, the Western Interior of Middle North America: ABSTRACT

Late Cretaceous Paleogeography, Sediment Accumulation, and Coal Distribution, the Western Interior of Middle North America: ABSTRACT

Late Cretaceous (Austin Group) Volcanic Deposits as a Hydrocarbon Trap: ABSTRACT

Late Cretaceous (Austin Group) Volcanic Deposits as a Hydrocarbon Trap: ABSTRACT

Holocene and late Last Glaciation pollen record from drillholes at Miramar and Lambton Harbour, Wellington, New Zealand

Abstract Pollen and spores obtained from condensed late Last Glaciation sequences of carbonaceous silts, with occasional gravel and peat horizons, from drillholes at Miramar and Lambton Harbour, Wellington, indicate a bleak, windswept, grassland/shrubland environment dominated by Poaceae. The dominant tree pollen type is Phyllocladus, probably P. alpinus. The 50.7 m thick Miramar sequence contains the Kawakawa Tephra at 24.5 m below ground level; this tephra was also identified in the field 16–17 m below ground level in two of the Lambton Harbour drillholes, the deepest of which went to 40 m. A disconformity exists between the late Last Glaciation sediments deposited immediately after deposition of the Kawakawa Tephra and the onset of Holocene sedimentation. This disconformity occurs in most sequences of this age in the Wellington area and is caused by unstable climatic and depositional conditions at the time. Recycling of spores, pollen, and dinoflagellates from Late Cretaceous and Cenozoic sediments occ...

The Kilen Expedition 1985

The 1985 expedition constitutes the first comprehensive investigation of the isolated, hyperarctic semi­nunatak Kilen in eastern North Greenland. Well over 3 km of generally marine, elastic sediments are preserved from the Late Jurassic to Late Cretaceous period. While half this amount accumulated in ·a comparatively stable tectonic regime prevailing during Late Jurassic and Early Cretaceous time, the Late Cretaceous (Turonian-Coniacian) sediments are characterized by their deposition in a local pull-apart basin developed in the regional Wandel Hav Strike-Slip Mobile Belt. Subsequent, localized compression along this belt has deformed the entire sequence rather severely in a complex series of en echelon domal folding and thrusting, most likely during the later part of the Cretaceous. Quaternary marine sediments of probable interglacial origin (> 100.000 years old) have been found to contain a mollusc fauna requiring temperatures above the present level. Flade lsblink, the largest local icecap in Greenland, is composed of several semi-independant ice domes, and there is evidence that the history of this icecap deviates significantly from that of the Inland Ice. A total of 34 species of higher plants, 29 species of birds, and 11 species of mammals have been recorded from Kilen; vegetation studies indicate a July mean temperature of around 2.5°C.

The Sredne-Amursky Basin: A Migrating Cretaceous Depocenter for the Amur River, Eastern Siberia

Recently acquired seismic, well, and regional geological data imply favorable conditions for the accumulation of oil and gas in the 20,000 km[sup 2] Sredne-Amursky basin. Major graben and northeast-trending sinistral wrench-fault systems are recognized in the basin. Lower and Upper Cretaceous sediments are up to 9000 and 3000 m thick, respectively. Paleogeographic reconstructions imply that during the Late Triassic-Early Cretaceous the Sredne-Amursky basin was part of a narrow marine embayment (back-arc basin), which was open to the north. During the Cretaceous, the region was part of a foreland basin complicated by strike-slip, which produced subsidence related to transtension during oblique collision of the Sikhote-Alin arc with Eurasian margin. Contemporaneous uplift also related to this collision migrated from south to north and may have sourced northward-directed deltas and alluvial fans, which fed northward into the closing back-arc basin between 130 and 85 Ma. The progradational clastic succession of the Berriasian-Albian and the Late Cretaceous fluvial, brackish water and paralic sediments within the basin may be analogous to the highly productive late Tertiary clastics of the Amur River delta in the northeast Sakhalin basin. Cretaceous-Tertiary lacustrine-deltaic sapropelic shales provide significant source and seal potential and potential reservoirs occur in the Cretaceous andmore » Tertiary. Structural plays were developed during Cretaceous rifting and subsequent strike-slip deformation. If the full hydrocarbon potential of the Sredne-Amursky basin is to be realized, the regional appraisal suggests that exploration should be focused toward the identification of plays related to prograding Cretaceous deltaic depositional systems.« less

Geological Prerequisites for Petroleum Potential of the Couple Moesian Platform and Fore-Balkan (Central Balkan Peninsula), Bulgaria

The Moesian platform and the Fore-Balkan are among the best developed structural elements in the Alpine morphostructure of the Balkans. Many authors considered them as foreland and fold belt, joined by an asymmetric, narrow foredeep. Almost all Mesozoic sedimentary units are similarly developed on the platform and in the Fore-Balkan, where they are involved in predominantly small brachystructures and linear, often isoclinal and larger folds, respectively. Late Jurassic and Early Cretaceous sediments were deposited on the platform in carbonate facies and in the Fore-Balkan as a thick turbidite sequence. The peri-platform concept for the transitional foredeep is currently under review and new approaches to the evaluation of its hydrocarbon potential are being developed. Several small oil and gas fields have been found in the Fore-Balkan and the foredeep. Major discoveries have been made on the Moesian platform, where more than 20 small and medium fields are known. These pools are structurally or stratigraphically trapped in Middle to Upper Triassic carbonates and Early to Upper Jurassic clastics. Traps are related to the relief of the lower Kimmerian unconformity, straddling the Triassic-Jurassic boundary. Additional accumulations are contained in Upper Jurassic-Lower Cretaceous carbonates. All sedimentary sequences contain disseminated organic matter and have reachedmore » maturity for the generation of hydrocarbons; however, no specific source rocks have been identified. Reservoirs are characterized by generally low intergranular and fracture porosity and permeability. During the past decades, the concept of a thrusted Fore-Balkan, overriding the foredeep, was gradually developed on the basis of well results. With the acceptance of this concept, the oil exploration strategy had to be changed. Combined structural and stratigraphic/sedimentological studies are required to resolve the evolution of the Fore-Balkan and its foredeep and to assess their hydrocarbon potential.« less

High-Resolution Sequence Stratigraphy from Outcrop Study, with the Integration of Log and Seismic Data

The detailed sequence stratigraphic analysis of the siliciclastic-dominated Late Cretaceous sediments (Aren Sandstone and Garumnian red beds, south central Pyrenees, Spain) reveals the repeating disposition of critical elements and controlling mechanisms of cycles and sequences. Our approach integrates (a) hierarchy of unconformity-bounded units, (b) physical expression of boundaries traceable from the continent to the basin, (c) featuring facies and depositional systems, (d) well log and seismic expression, and (e) driving basing-filling mechanisms. A comparison to other active basins is suggested in order to prove the validity beyond the regional scale. Four basin-wide transgressive facies cycles were identified and interpreted as third-order units. The transgressive phase of each cycle is represented by mixed shelf deposits, while regressive periods consists of complex delta systems. The cycles are composed within their regressive phase of fourth-order depositional sequences, trapped in structural lows, which are controlled by synsedimentary compressive tectonics. Both cycles and sequences are set up by similar building blocks. Our example, cycle two, localized in the Tremp area, displays seven sequences: lowstand systems tracts are channelized turbidites; transgressive systems tracts are lagoon-barrier systems and/or storm-dominated shoreface deposits; and fluvial, coastal plain, and delta deposits build highstand systems tracts. The physical continuity of themore » sequences (and cycles) is frequently disrupted by erosion due to lowstand or transgressive processes and active faulting. Synsedimentary ramp anticlines, which control the entire basin, and third-order unconformities have been recognized in seismic lines. Their interpretation has led to the identification and correlation of cycles and sequences in the well logs of the region.« less

Palynology of an upper cretaceous section in the Borod basin (north-west Romania)

The scattered outcrops of Late Cretaceous deposits in the Borod Basin encompass different stratigraphic intervals. A section at Cornilel in north-west Romania has yielded a Normapolles assemblage, the composition of which supports an age determination of Santonian-early Campanian, suggested previously on the basis of the fauna it contains. The assemblage correlates with palynostratigraphical subdivision “f” already established for the Cretaceous sequence in the Southern Apuseni Mountains.

Petroleum geochemistry of some Late Cretaceous shales from the Lokoja Sandstone of Middle Niger Basin, Nigeria

Organic geochemical analyses of shales from an extensive Late Cretaceous deposit of Lokoja Sandstone (Middle Niger Basin) has been carried out in an attempt to assess their petroleum potential. The organic carbon content of the exposed argillaceous sediments (total thickness sampled 100 m) ranged from 0.34–2.53 wt. % with an overall average of 1.95 wt. %. This exceeded the minimum threshold (0.5 wt. %) needed for petroleum generation and in the first instance classified the units as potential source beds. Evidence from biomarkers including n-alkanes and triterpanes indicated a preponderance of terrigeneous organic matter with some marine input. The sedimentological evidence indicates deposition in a fluviatile or palludal environment. Rock-Eval pyrolysis data confirmed mixtures of Type III-II and Type III kerogen which correspond to organic matter derived from Marine-terrestrial (transitional) and continental palaeoenvironments. Moreover the epicontinental sea that flooded the basin was more marine towards the north thereby implying a possible source from the Maestrichtian Tethys transgression. Maturity assessment based on pyrolysis and biomarker parameters showed that the shales of the Lokoja Sandstone were thermally immature and were unlikely to have generated significant quantities of petroleum. The most promising areas seem to be north of this study where source rocks that have attained optimum levels of maturity for hydrocarbon may occur.

Provenance changes and movement on the Alpine Fault indicated by heavy minerals from Cretaceous-Cenozoic sediments in south Westland

Abstract Late Cretaceous sediments of south Westland contain only ultra-resistant heavy minerals suggesting that there has been substantial intrastratal solution, or that strong chemical weathering was active in the provenance area. The lower part of the Paleocene Tokakoriri Formation is strongly volcanic, but in the upper part the dominant influence was granite or hornfels and (probably associated) older sedimentary rocks such as Greenland Group. Miocene to Recent sediments record a sequence of pronounced changes of provenance. The upper Miocene Tititira Formation shows the early Tertiary source continuing, with increased influence from another granite or altered older sediments. The base of the early Pliocene Halfway Formation is marked by an abrupt flood of hornblende, presumably from Fiordland, though the Tititira source also continues. The influence of hornblende declines towards the top of the formation, and is further reduced (though still prominent) in the overlying “Teer unit”. The Pleistocene Cascade Conglomerate is flooded by olivine from Red Mountain ultramafics. Recent sediments with less olivine and more pyroxene suggest greater influence from more serpentinised ultramafics north of Red Mountain. The sequence of source areas is consistent with the hypothesis that most displacement on the Alpine Fault has taken place since the Miocene.

Pollen evidence for Late Cretaceous differentiation of Proteaceae in southern polar forests

Amongst diverse and abundant fossil proteaceous pollen in southeastern Australian Late Cretaceous (Campanian–Maastrichtian) sediments are forms identical with pollen of extant taxa within subfamilies Proteoideae, Persoonioideae, Carnarvonioideae, and Grevilleoideae. Taxa identified now have disparate geographic ranges within Australasia. Sclerophyllous Adenanthos and Stirlingia (Proteoideae) are restricted to the southern Australian Mediterranean climatic region; Persoonia (Persoonioideae) ranges into higher rainfall areas of eastern and northern Australia. Grevillea exul – Grevillea robusta and Telopea (Grevilleoideae) and Carnarvonia (Carnarvonioideae) occur in or fringe rain forests in eastern Australasia, as do other members (Macadamia, Gevuina–Hicksbeachia, Knightia, and Beauprea) reported previously. Pollen evidence thereby confirms evolution of both rain forest and sclerophyll members by the Campanian–Maastrichtian. Turnover of proteaceous pollen taxa near the Cretaceous–Tertiary boundary may reflect contemporaneous modifications to the proteaceous communities. Associated with the Late Cretaceous Proteaceae were diverse conifers (Microcachrys, Lagarostrobus, Podocarpus, Dacrydium, Dacrycarpus, and Araucariaceae), Nothofagus, Ilex, Gunnera, Ascarina, Winteraceae, Trimeniaceae, and probable Epacridaceae. The vegetation, which fringed a narrow estuary separating Antarctica from southern Australia, implies a mosaic of rain forest and sclerophyll communities but has no modern analogue. Key words: Proteaceae, Late Cretaceous, Australia, Antarctica.