Maestrichtian Age Research Articles

A new evidence of cretaceous echinoids at the region Paleokastro of Stylis area (Fthiotida district)

The rich Fauna of Echinoids (114 individuals) coming from the region Paleokastro Fthiotida has been found for the first time in Greece. The most part of the Echinoids studied, belongs to the genus Echinocorys{12%), and in minor quantity to the genus Micraster(8%), Galeaster(l%) and Coraster(19%). 17 species has been indentidied which have been distributed 13 to the genus Echinocorys ( E. conoideus, E. gravesi, E. humilis, E. lamberti, E. marginatus, E. obliquus, E. ovatus, E. pyramidatus, E. rectus, E. sulcatus, E. turritus, E. vulgaris, E. zejszneri), 1 to the genus Micraster (M. coranguinum), 1 to the genus Galeaster (G. cf. bertrandi) and 2 to the genus Coraster (C. sphaericus, C. frechi). The accompagnied fauna is consisting of one Scleractinian (Caryophyllia sp.) and one Nautiloid (Eutrephoceras dekayi (MORTON)). The stratigraphical distributions of the studied fauna allow us to accept that the cretaceous layers with the Echinoid Fauna belong to the Upper Maestrichtian age. The studied fauna, with his monotonous character, is an ecological niche of the genus Echinocorys living in almost littoral waters.

Ostracode fauna from the Patti Formation (Late Cretaceous) of Vridhachalam area, Tamil Nadu, India

An ostracode fauna is recorded from the Patti Formation (Late Cretaceous) of Vridhachalam area, Tamil Nadu. The assemblage includes Bairdia pentagonalis, B. cretacea, B. supplanata, Macrocypris limburgensis and Paracypris limburgensis, which are typical of Maestrichtian age. The ostracodes show strong affinities with those recorded from the Ariyalur and Pondicherry areas, and those described from the type-Maestrichtian of Holland. The above assemblage and the presence of distinct Paleocene ostracodes in the overlying Pondicherry Formation throw light on K/T transition in the Vridhachalam area. The paper also discusses the stratigraphic distribution and zoogeographic affinities of the ostracode fauna with equivalent formations in India and the type areas elsewhere.

Oceanic, Island Arc, and Back-Arc Remnants into Eastern Kamchatka Accretionary Complexes: ABSTRACT

The Kamchatsky Mts. accretionary complex in the Eastern Kamchatka orogenic belt was studied for identification of the oceanic and suprasubduction components into accretionary wedges. That complex is divided into two tectonic units. The Lower unit is formed sedimentary and tectonic melanges containing arc-related components (Late Senonian volcaniclastics and boninitic gabbro) and oceanic fragments (Fe-Ti-tholeiites, ocean island basalts, and pelagic sediments of Valanginian to Turonian age). The Upper unit consists of ductile deformed oceanic cumulates from troctolites to Fe-Ti-gabbro, 151 to 172 Ma, which are intruded MORB-like diabases with suprasubduction characteristics, 122 to 141 Ma, and are overlain by basalts similar to latter. The Lower and Upper units are separated by a SW-dipping thrust, which is related by an ophiolitoclastic olistostrome of Late Campanian to Early Maestrichtian age. Both units are covered by Paleocene authoclastic deposits. They are all thrusted over the early Neogene island arc complex, 16 to 20 Ma. The Lower unit of the Kamchatsky Mys accretionary complex was originated in a shear zone between a Late Cretaceous island arc and an Early Cretaceous oceanic plate. The Upper unit represents a Jurassic oceanic remnant that formed a basement of Early Cretaceous back-arc or fore-arc basin. Both units were superposedmore » in the latest Cretaceous. The Kamchatsky Mys accretionary complex was emplaced into the Eastern Kamchatka orogenic belt during late Neogene by collision of the early Neogene island arc.« less

Dinoflagellate species and organic facies evidence of marine transgression and regression in the atlantic coastal plain

Palynological evidence is used to date and interpret depositional environments of sediments of Campanian, Maestrichtian and early Danian ages cored in three wells from South Carolina and Georgia. The evidence is usefil for distinguishing environments which lithofacies evidence indicates a range from nonmarine to coastal to inner neritic shallow shelf. Numerous dinoflagellate species and an organic facies defined abundant amoprphous debris (amorphous debris facies) distinguish shallow shelf sediments deposited during marine transgression. The nearshore amorphous debris facies of late Campanian age consists of heterogenous assemblages dominated by Palaeohystrichophora infusorioides Deflandre or Hystrichosphaerina varians (May). The farther offshore amorphous debris facies of late early Maestrichtian to late Maestrichtian age consists of heterogenous assemblages dominated by Glaphyrocysta retiintexta (Cookson) and/or Areoligera medusettiformis (Wetzel). The larger number of dinoflagellate species in the offshore facies represents the maximum transgression detected in the investigated interval. A multiple occurrence datum defined by the combination of first appearance, klast appearances and sole occurrence of dinoflagellate species at the base of each interval distinguished by the amorphous debris facies provides the first evidence of marine transgression. Relatively small organic residues consisting of intertinite and few or no palynomorphs define the inertinite facies in nonmarine deltaic and in coastal (lagoonal, tidal flat, interdistributary bary) sediments. Dinocyt☆s are absent in the nonmarine sediments and are represented by few species and few specimens in the coastal inertinite faceis. A third organic facies (vascular tissue facies) is defined by the abundance of land plant tissue. Sporomorph species, including those of the Normapolles pollen group and of pteridophyte spores, comprise a large proportion of the total palynomorph flora in the inertinite and vascular tissue facies. The vascular tissue facies occurs in the proximal prodelta and nearshore shallow shelf lithofacies of early Maestrichtian age. Baed in the sequence of organuic facies, dinoflagellate species abundance, and lithofacies in the investigated wells, the nonmarine and coastal inertinite facies was first deposited and was followed during the late Campanian by a marine trangression when the nearshore amorphous debris facies was deposited. This was followed in the early Maestrichtian by the influx of terrigenous organic matter (vascular tissue facies) in response to deltaic progradation on the shallow shelf. A marine regression occured towards the close of the early Maestrichtian, emplacing the coastal inertinite facies. The major marine transgression occured near the end of the early Maestrichtian, developing a farther offshore amorphous debris facies on an expanded continental shelf which persisted through the late Maestrichtian. The inertinite facies returned during marine regression in the approximate position of the Maestrichtian/Danian boudnary.

Petrology and Provenance of Upper Cretaceous Sandstone, Southern San Rafael Mountains, Santa Barbara County, California: ABSTRACT

Petrologic analysis of 24 medium to coarse-grained sandstone samples, collected from a 2950-m submarine fan complex of late Campanian-early Maestrichtian age exposed within Mono Creek Canyon, reveal commonly calcite cemented, poorly sorted, subangular biotic arkoses. Framework averages 86.0%. Matrix - primarily detrital quartz, feldspar, and lithic fragments finer than 0.03 mm and mechanically and chemically altered phyllosilicates and labile aphanites - averages 8.9%. Calcite cement averages 4.2%. Porosity averages 0.9%. Gazzi-Dickinson point counts of 400 framework grains per slide yield modal averages of Q/sub 37.7/ F/sub 49.8/ L/sub 12.5/; Qm/sub 27.4/ F/sub 49.8/ Lt/sub 22.8/; Qm/sub 35.6/ P/sub 43.7/ K/sub 20.7/; and Qp/sub 49.4/ Lv/sub 22.1/ Ls/sub 28.5/. P/F averages 0.68, Lv/L averages 0.45, Qp/Q averages 0.27, and detrital phyllosilicate, predominantly biotite, averages 5.7% of total framework. Neither primary nor secondary parameters vary systematically with stratigraphic position. Miscellaneous constituents average 1.3% of framework and include epidote, garnet, amphibole, pyroxene, zircon, and tourmaline as well as carbonaceous blebs, opaque minerals, and unidentifiable lithic fragments. Separate analysis of 100 medium sized quartz grains per slide indicates a mean population of 63.0% non-undulatory monocrystalline quartz, 9.1% undulatory monocrystalline quartz, 10.1% polycrystalline quartz of 2 to 3 crystals, and 17.9% polycrystalline quartz composed ofmore » more than 3 crystals. Modal data, plotted upon provenance discrimination diagrams, indicate a plutonic provenance transitional between a dissected magmatic arc and uplifted basement terrane. Paleocurrent data, neglecting possible clockwise rotation, indicate sediment transport from the north.« less

Paleogene accretion of Upper Cretaceous oceanic limestone in northern California

Blocks of pelagic limestone, tectonically incorporated into coastal terrane melange, contain planktonic foraminifers of early Campanian to middle Maestrichtian age (82-69 Ma) typical of low latitudes between 20°N and 20°S. Carbonate concretions from the sheared terrigenous matrix of the melange yield temperate, middle-latitude planktonic foraminifers and dinoflagellates of middle to late Eocene age (49-41 Ma). The pelagic limestone and the basaltic substrate presumably formed on the eastern flank of the Pacific-Farallon spreading ridge in a low-latitude zone of high productivity and migrated northward on the Farallon plate until about 40 Ma when they initially encountered terrigenous turbidites north of lat. 30°N. Northward translation and final accretion were completed by about 25 Ma.

Stratigraphy and Palynology of the Upper Lewis Shale, Picture Cliffs Sandstone, and the Lower Fruitland Formation (Upper Cretaceous) near Durango, Colorado

The stratigraphy and palynology of Upper Cretaceous units (upper Lewis Shale, Pictured Cliffs Sandstone, and lower Fruitland Formation) were investigated near Durango, Colorado, on the northern rim of the San Juan basin. This investigation: (1) confirms an interdeltaic depositional setting for these formations in the study area, (2) provides new biostratigraphic data for the Upper Cretaceous rocks on the northern rim of the San Juan basin, and (3) indicates a mostly freshwater origin for the Carbonero coal bed at the base of the Fruitland Formation. The upper Lewis Shale was deposited in lower offshore to upper offshore marine environments. The Pictured Cliffs Sandstone records a major regression on the western margin of the Late Cretaceous sea. The northeastward regression was not one steady event but a series of superimposed transgressive pulses. The depositional environments identified in the Pictured Cliffs Sandstone are upper offshore, shoreface, foreshore, and backshore. The lower part of the Fruitland Formation represents a coastal swamp deposit which developed just landward of the Pictured Cliffs Sandstones. The Carbonero coal bed lies at the base of the Fruitland Formation. At one location, a small tidal channel developed and inundated the local swamp environment. Ten Late Cretaceous palynomorph guide fossils were identified in the Lewis Shale, Pictured Cliffs Sandstone, and Fruitland Formation. The palynomorphs of the Lewis Shale and Pictured Cliffs Sandstone are a marine assemblage. The Fruitland Formation contains a terrestrial assemblage of pollen and spores. Trudopollis meekeri, Kuylisporites scutatus, and cf. Myrtaceoipollenites are a late Campanian Stage palynomorph assemblage in the Fruitland Formation. These findings refute the recent interpretation of a late Maestrichtian age for the Fruitland Formation. The palynological results obtained in this research can be used for correlation and mapping of interbasin and intrabasin sedimentary facies.

Late Cretaceous mammals ( Marsupialia) from Bolivia

A second Late Cretaceous (Maestrichtian Age)mammal fauna for South America was recovered from the El Molino Formation in southcentral Bolivia. Three species are referred to the marsupial super-family Didelphoidea. The most abundant species has marked bunodont dental specializations which are convergent with some early placental Condylarthra; it is named and is tentatively placed in the didelphid subfamily Caroloameghiniinae.

Preservational effects in paleoecological studies: Cretaceous mollusc examples

The effect of preservational quality on paleoecologic studies is evaluated quantitatively by using data from 83 fossil collections. These collections are from a restricted Cretaceous time interval (Haustator bilira Assemblage Zone) of Maestrichtian Age and are from the Eastern Gulf Coastal Plain Province. In all, 32,335 specimens were identified, resulting in recognition of 643 different taxa. Each collection was categorized into one of six preservational types, ranging from those in which both aragonite and calcite shells are well preserved to those having only calcite shells preserved.Statistical comparisons reveal that preservation affects the faunal makeup of these collections. Specifically, collections in which both aragonite and calcite are well preserved have more taxa than collections of poorer preservational quality and contain faunal elements not found in other collections.These two effects can confound paleoecologic studies of endemism, eurytopy vs. stenotopy, species longevity and other studies of the distribution of organisms in space and time. These effects are especially significant for studies based on presence/absence data, such as published faunal lists and selectively collected samples. In such studies, collections of good preservational quality may be interpreted to represent strata of high diversity, taxa having the more durable hard parts will appear to be widespread and long ranging, and taxa that are preserved only in collections of the best preservational quality will appear stenotopic, endemic, and rare.

Review of the Upper Cretaceous–Lower Tertiary sequence on Seymour Island, Antarctica

The thick sequence of fossiliferous marine and non-marine sandstones and siltstones on Seymour I. represents the most complete well-exposed section of Upper Cretaceous to Lower Tertiary rocks known in the Southern Hemisphere. The succession has been divided into the Upper Campanian to possibly lowermost Tertiary Marambio Group comprised of the Lopez de Bertodano and Sobral formations and the Lower Tertiary Cross Valley and La Meseta formations of the Seymour Island Group. The Lopez de Bertodano Formation consists of c . 1067 m of medium-grained to silty concretionary sandstones of Middle Campanian to possibly Maestrichtian age, and the Sobral Formation of c . 210 m of medium- to coarse-grained glauconitic concretionary sandstones. The precise age of the Sobral Formation is uncertain, but may be Maestrichtian to possibly Danian. The lower 110 m of the Seymour Island Group consists of non-marine gravelly to pebbly sandstones and tuffaceous plant-bearing siltstones of the Cross Valley Formation, overlying which are 450 m of fine-grained marine sandstones and siltstones with interbedded fossiliferous pebbly conglomerates. Recent studies of the diverse and abundant faunas and floras of the Seymour Island Group have shown that they are older than previously thought, the Cross Valley Formation being Palaeocene and the La Meseta Formation late Eocene to possibly earliest Oligocene.

The ophiolitic Bath-Dunrobin Formation, Jamaica: significance for Cretaceous plate margin evolution in the north-western Caribbean

Two neighbouring areas of tholeiitic basalts, dolerites, isotropic gabbros and tonalites in eastern Jamaica are recognized as the upper section (~2.5 km thick) of an ophiolite. Limestones associated with this Bath-Dunrobin Formation contain a fauna of Upper Campanian and Lower Maestrichtian age. The basalts are overlain by a thick sequence of Maestrichtian volcaniclastic rocks and are faulted against a blueschist terrain. Since its emplacement the ophiolite has been subjected to uplift and major left-lateral strike-slip tectonism beginning in the Eocene. Recognition of this subduction zone complex and regional considerations of island arc polarity necessitates that ocean crust must have been consumed by a southward-dipping subduction zone. The overlying late Cretaceous/Palaeogene arc stretched from Guatemala through Jamaica to Oriente Province, Cuba. This arc separated the Yucatan Basin to the N, where active spreading accompanied subduction, from the Colombian Basin and the southern Nicaraguan Rise to the SE, where tholeiitic magmatism (B") penetrated older ocean crust. The Bath-Dunrobin Formation probably represents ocean crust from the Yucatan Basin obducted during the Maestrichtian. The major ophiolite terrains of Guatemala and Oriente, Cuba are by inference also derived from a proto-Yucatan Basin.

Cretaceous Arctic silicoflagellates

Cretaceous silicoflagellate assemblages from Arctic Ocean USGS Core 437 showVallacerta siderea the most abundant species; most species ofLyramula disappear halfway up the core; onlyL. burchardae, n. sp., persists into the upper sections. These occurrences are untypical of the few documented Cretaceous assemblages from other areas. A Campanian or Maestrichtian age is suggested by correlation, but the uniquely high abundance ofV. siderea and lack ofCorbisema suggests that a difference in both age and general environment could be involved. If Core 437 is latest Maestrichtian, then the evidence from this core would constrain the timing of the ocean-freshening model for the Cretaceous-Tertiary boundary extinctions.

Examen microscopique et analyse à la microsonde des céramiques "Base Ring" du Chypriote Récent

Cypriote Base-Ring Ware (Hand-made) ceramics of the Late Bronze Age can be distinguished from other pottery types by their thin walls and sonorous qualities (called Metallic Ware). The exact geographic source of this pottery has not been identified archaeologically. Pétrographie microscope and electron microprobe studies indicate that the Base-Ring Ware is made from clays rich in ferric illite and micas. Mineral analysis indicates that the source of the clays must be limited to outcrops of the "Mamonia Formation" situated both in the Kyrenia Range to the North and in the Southwestern part of Cyprus (rocks of Triassic to Early Maestrichtian Age).

Cretaceous Stratigraphy, Chignik Area, Alaska Peninsula, Alaska: ABSTRACT

Lower and Upper Cretaceous strata in the Chignik area were deposited in a fore-arc basin along an intermittently active continental-plate margin. The Lower Cretaceous part is preserved in a limited area and consists of 98 m of shallow-marine sandstone, rich in Inoceramus prisms, and shale of Valanginian to Hauterivian(?) age. These rocks are correlated with the Herendeen Limestone, which crops out 160 km to the southwest. Upper Cretaceous strata in the Chignik area comprise the Chignik Formation of Campanian age and the Hoodoo Formation of Campanian to Maestrichtian age. In the Chignik Bay area, the Chignik is composed of 550 m of predominantly deltaic shoreface sandstone overlain by about 300 m of predominantly nonmarine coastal-plain facies; at least 15 transgressive-regressive cycles are recognized. Oil staining is common in more permeable, coarser grained sandstones in the Chignik Bay Figure area. About 14 km to the northwest, the Chignik Formation is dominantly nonmarine and is less than 400 m thick. Thick conglomerate units and at least one intraformational unconformity indicate continuing tectonic activity in the source area located to the northwest. The Hoodoo Formation conformably overlies, and in part intertongues with, the Chignik Formation. The Hoodoo consists of 600 m of deep-water silty shale with local turbidites and slope-channel conglomerates. Lower Tertiary strata unconformably overlie the Hoodoo. End_of_Article - Last_Page 752------------

Quantitative palynologic correlation of three Campanian and Maestrichtian sections (upper cretaceous) from the Atlantic coastal plain

Abstract Attempts were made to correlate lithostratigraphic units of Campanian and Maestrichtian Age from the Raritan, Salisbury, and Okefenokee embayments of the Atlantic Coastal Plain by using cluster analysis and principal coordinates analysis of selected species of angiosperm pollen. These attempts resulted in the recognition of major biostratigraphic subdivisions but failed to provide the degree of biostratigraphic resolution sought. The lack of resolution is attributed primarily to undetected rates of micro‐floral change throughout the sections and secondarily to distortion of the data matrix in the multivariate analyses. A new technique, referred to as Similarity Coefficient Matrix Contouring (SCMC), was applied to data in order to minimize matrix distortion. A comparison of the correlations suggested by SCMC with those arrived at by cluster and principal coordinates analyses indicates that, in this study, SCMC provided a graphic representation that led to detailed correlations. The detailed correl...

Alpha Radioactivity of the Constituent Particles in Some Pelletal Phosphorites from Safaga and Other Localities in Egypt

ABSTRACT The uranium content of diverse pelletal phosphorite beds of Maestrichtian age in Egypt, as indicated by alpha radioactivity determined by autoradiographic nuclear emulsion techniques, is usually unequally distributed among the constituents of the phosphate rock. The most radioactive parts are those dark, almost opaque bituminous, blackish, brownish or reddish pellets, probably after original fecal pellets with a relatively high content of organic matter. Bone fragments, chiefly after fish and reptilian teeth, are less radioactive, but the amorphous (mostly isotropic under crossed nicols) clear or zonally to patchily colored collophanite pellets have intermediate radioactivities. Non-phosphatic limestone or chert lithoclasts as well as epigenetic intergranular carbonate cements or late diagenetic theft cements in the pelletal phosphorites are the least radioactive. External surfaces of a minority of large phosphatic pellets, and particularly of large reptilian bones are more radioactive than their interiors. Average specific radioactivity values are given for the different constituents of some pelletal phosphate beds near Port Safaga.

Paleobathymetry of Cretaceous Turbidite Basins of the East Alps Relative to the Calcite Compensation Level

The paleobathymetry of ancient turbidite basins has traditionally been dealt with in terms of paleontologic depth indicators. The calcite compensation depth now provides an additional bathymetric reference level. In this study the concept of carbonate compensation levels (CCL) has for the first time been applied in detail to Cretaceous turbidite basins. Out of the four East Alpine basins studied two (i.e., Flysch Zone of the East Alps and Kossen Gosau Basin) have calcite-free hemipelagic green claystones of Campanian-Early Maestrichtian age and were below the CCL. Alternative causes such as climatic variations and terrigenous influx of carbonate-free detritus are unlikely to be major controlling factors for the absence of calcite in the hemipelagic claystones. Distinction between hemipelagic and turbiditic mudstones is facilitated by the high calcium carbonate content of the latter. Hemipelagic and pelagic layers of the same age in the other two basins (Reichenhall Gosau Basin and Ultrahelvetic flysch) co...

Longusorbis cuniculosus: A New Genus and Species of Upper Cretaceous Crab; with Comments on Spray Formation at Shelter Point, Vancouver Island, British Columbia

Eighty-three fossil crabs, belonging to a new genus and species, and interpreted to be mainly exuviae, were collected from concretions within the Spray Formation at Shelter Point, Vancouver Island, British Columbia. They are assigned to the family Carcineretidae and named Longusorbis cuniculosus. The excellent preservation of the fossil crabs is a consequence of being buried in their own dwelling burrows in the intertidal zone, and subsequent formation of concretions around the specimens very early during diagenesis. Several species of mollusc occur with the crabs, and the faunal assemblage is assigned to the Pachydiscus suciaensis Zone of late Campanian to early Maestrichtian age. The small part of the Spray Formation exposed at Shelter Point contains six units of detrital sediment deposited in environments inferred to range from shallow neritic to supratidal.

Relation of Rocky Point Member (Peedee Formation) to Cretaceous-Tertiary Boundary in North Carolina

The Rocky Point Member of the Peedee Formation (Cretaceous of North Carolina), exposed in quarries near Castle Hayne and Rocky Point, was named informally by Swift and Heron and herein is designated formally as a stratigraphic unit. In the type section, it consists of 10.5 m of pelecypod biosparrudite, unconsolidated quartz arenite, and an alteration of the two. The invertebrate macrofauna and microfauna indicate a Maestrichtian (= Navarro) age. Confusion has arisen over the problem of real or supposed mechanical mixing of faunas between Upper Cretaceous units and the overlying Castle Hayne Formation of Eocene age. The Rocky Point Member is overlain with spectacular unconformity by a hard phosphate-pebble conglomerate which is the basal bed of the Castle Hayne Formation. This conglomerate has some reworked Cretaceous fossils together with Eocene fossils, as first indicated by Tuomey. The underlying Rocky Point Member has more resemblance to some Castle Hayne outcrops in North Carolina than it does to the typical glauconitic, argillaceous sands of the Peedee Formation. It is probably because of this fact that the idea of mechanical mixing of faunas, moderately true for the basal Castle Hayne conglomerate, has been extended inc rrectly to include the Rocky Point Member. The presence of unworn, delicate specimens of the echinoid, Hardouinia, and a spiny Exogyra mitigate against any notable amount of abrasion. This, coupled with the presence of exclusively Cretaceous foraminiferal species and the absence of any exclusively Eocene species, makes the mechanical-mixing theory inapplicable to the Rocky Point Member. The Cretaceous-Tertiary boundary is the conspicuous unconformity between the Castle Hayne Formation and the Rocky Point Member of the Peedee Formation in southeastern North Carolina.

Mesozoic Fossils from Augustine Island, Cook Inlet, Alaska: GEOLOGIC NOTES

Upper Jurassic and Upper Cretaceous fossiliferous marine strata are present on the south flank of Augustine Volcano. The Late Jurassic rocks contain Buchia concentrica as well as the first reported Buchia piochii (Gabb) from the Cook Inlet area, indicating a possible correlation with the upper part of the Naknek and lower part of Staniukovich Formations of the Alaska Peninsula. The Upper Cretaceous rocks contain fossils of Campanian to Maestrichtian age and are correlative with the Kaguyak Formation of the Katmai area.