Middle Campanian Age Research Articles

Lithostratigraphy and Biostratigraphy of the Shiranish Formation (Late Campanian- Maastrichtian) in Diana area, Northern Iraq

The lithostratigraphic and biostratigraphic studies of the Shiranish Formation in the Diana area, Erbil, Northern Iraq, were conducted to distinguish the main lithostratigraphic units, depositional environment and the formation age. The Shiranish Formation in the study area can be divided into three rock units. The lower and upper units consist of marly limestone, marl and limestone deposited in the outer shelf environment, while the middle unit is dominated by laminated calcareous shale and marl deposited in the upper bathyal environment. Calcareous nannofossils showed the presence of about 20 species/genera in the studied Shiranish Formation. Three biozones are identified; Misceomarginatus pleniporus biozone; Ceratolithoides aculeus biozone, and Uniplanarius sissinghii biozone. From a regional perspective, these biozones were compared with other nannobiozones, leading to the conclusion that the studied section is of Middle Campanian age.

Cretaceous (Aptian-Maastrichtian) stratigraphy of the Shiranish Islam area, northern Iraq

ABSTRACT: The Kurdistan region of northern Iraq contains world-class outcrops that make it possible to examine the Cretaceous deep and shallow marine Tethyan faunal succession. Six separate sections covering the Shiranish, Bekhme, Mergi and Qamchuqa formations have been investigated in this study from the Shiranish Islam area. A number of papers have been published on this area, but no comprehensive biostratigraphic record has been published that fully documents the Cretaceous stratigraphy and the chronostratigraphic interpretation of the succession. As a result, this has led to significant lithostratigraphic and chronostratigraphic uncertainties. The upper part of the Qamchuqa is pervasively dolomitized. Rare occurrences of foraminifera are found in less dolomitized intervals in thin-section indicating an early - middle Albian age for the top of the formation. A thin interval comprising the Gir Bir Formation is Cenomanian in age and is present between the top of the Qamchuqa Formation and the overlying conglomerate. Historical studies indicate that the Turonian Mergi Formation occurs between the Qamchuqa and Bekhme formations, but our field and analytical data does not support it as a discrete lithostratigraphic entity, as Turonian aged faunas were not recognized. The conglomerate separating the top of the Gir Bir and base of the Bekhme is subdivided into three units (A, B & C). Units A and B are late Cenomanian to early Turonian age, whilst Unit C is of Campanian age. A significant hiatus separates the Gir Bir and the Bekhme, which encompasses the intra Turonian to Santonian. The limestone facies of the lower part of the Bekhme Formation contains rich benthic foraminiferal faunas (miliolids, Pseudedomia, Cuneolina) of early - early middle Campanian age. This lower - lower middle Campanian section at Shiranish Islam is considered to be equivalent of the upper part of the Sa'di Formation in central Iraq and is therefore re-assigned on the basis of chronostratigraphic attribution to the Sa'di (equivalent) herein. The top of the early - early middle Campanian biofacies is abruptly truncated by an omission surface, marked by an erosive base, an influx of clastic material and a major up-section biofacies change characterized by an influx of Pseudosiderolites and Orbitoides representing an intra-Campanian hiatus. The bioevent sequence suggests that this hiatus at Shiranish Islam comprises at least the middle Campanian (upper part of the G. elevata Zone) into the late Campanian (intra R. calcarata Zone), from approximately 80.64 Ma to 76.09 Ma with 4.55 my missing. The middle part of the Bekhme Formation comprising the Pseudosiderolites - Orbitoides facies is thin (c. three meters) and is re-assigned to the Lower Bekhme Member. The boundary between the Lower Bekhme Member and the Upper Bekhme Member is conformable and marked by a gradual up-section reduction in the size and presence of larger benthic foraminifera (Orbitoides, Pseudosiderolites) and an increase in the planktic component (small planktics and calcispheres). This trend of gradually increasing water depth continues into the Shiranish Formation, with no apparent major breaks in deposition. The Campanian - Maastrichtian boundary falls within Unit A of the Shiranish Formation. Deposition of the Shiranish continued into the earliest late Maastrichtian and is unconformably overlain by the Danian Kolosh Formation. The hiatus between the top of the Cretaceous and the Paleocene extends from the early late Maastrichtian (c. 68.86 Ma) to the upper part of the Danian (62.2 Ma) with an estimated duration of 6.66 my.

Larger foraminifera and strontium isotope stratigraphy of middle Campanian shallow-water lagoonal facies of the Pyrenean Basin (NE Spain)

The Upper Cretaceous Terradets Limestone of the south Pyrenean Basin consists of two subunits, named the Lower Terradets and the Upper Terradets. In the Lower Terradets subunit, sedimentological features and fossil content permit distinguishing mid-ramp, bioclastic shoal and inner-ramp lagoonal facies associations, each characterized by a distinctive larger foraminiferal assemblage. Mid-ramp facies contain epibenthic, relatively small foraminifera like Cuneolina cylindrica, Dictyopsella cf. cuvillieri, Pseudocyclammina sphaeroidea, Nummofallotia cretacea, Fallotia? sp., Pararotalia cf. tuberculifera, Praestorrsella roestae and Praesiderolites praevidali. Bioclastic shoal facies are dominated by Orbitoides cf. tissoti, Praesiderolites douvillei, and Pseudosiderolites sp. The inner-ramp lagoonal facies contain a rich and diverse assemblage of epiphytes, like Ilerdorbis decussatus, Dicyclina schlumbergeri, and Cyclopsinella roselli n. sp., and epibenthic foraminifera, like Calveziconus lecalvezae and Orbitokathina campaniana. Strontium isotope stratigraphy indicates a middle Campanian age for the Lower Terradets limestone.

Cheilostome Bryozoa from the Upper Cretaceous Himenoura Group, Kyushu, Japan

Cheilostome bryozoans (Phylum Bryozoa; Order Cheilostomata) originated in the latest Jurassic but remained at low diversity until the late Albian–early Cenomanian, when they began an explosive radiation that has continued to the present day. Most knowledge of Late Cretaceous cheilostomes comes from Europe and the USA from deposits associated with the western Tethys Ocean. Only a few previous records of Cretaceous bryozoans exist from the margin of eastern Asia in the NW Pacific. We examined material from four localities of early– middle Campanian age in the Himenoura Group, Shimokoshikijima Island, Kagoshima Prefecture, southern Kyushu, Japan, and detected six cheilostome species but no cyclostomes. Two species were relatively common. For one of these, we erect the new genus Kenocharixa and describe a new species, Kenocharixa kashimaensis; we also transfer Charixa goshouraensis Dick, Komatsu, Takashima, and Ostrovsky and Conopeum stamenocelloides Gordon and Taylor to Kenocharixa. We describe the other common species as Marginaria prolixa sp. nov. We detected four species as a single specimen each and identified them only to genus (Charixa sp. A) or listed them as Incertae sedis (A, B and C). Among the six cheilostomes, five are primitive anascan-grade (malacostegan) species and one is an anascan-grade neocheilostome. Compared to Campanian–Maastrichtian bryozoan faunas in Europe and the USA, the Himenoura fauna is low in diversity and morphological disparity, with no cribrimorph or ascophoran species detected. Previous researchers have suggested that the NW Pacific biota became isolated from that of the Tethys in the latest Aptian–middle Albian interval. We advance the hypothesis that the Late Cretaceous bryozoan fauna in the NW Pacific is a low diversity relict of the fauna present when this isolation occurred. While Tethyan cheilostome lineages underwent a major radiation associated with the origins of cribrimorph and ascophoran frontal shields, the NE Pacific lineages failed to diversify at the same rate and remained at low diversity and disparity. Testing this hypothesis will require much further sampling in Cretaceous deposits along the margin of East Asia.

A LATE CRETACEOUS SHARK COPROLITE WITH BABY FRESHWATER TURTLE VERTEBRAE INCLUSIONS

A small (3.4 cm) coprolite from the Upper Cretaceous (middle Campanian age) Coachman Formation in South Carolina, contains six cervical vertebrae from a very small, freshwater, trionychid turtle. Four of the vertebrae included in the coprolite are aligned and partly articulated. The coprolite shows typical selachian heteropolar shape with traces of spiral morphology, and is attributed to one of several common lamniform shark taxa in the associated marine fauna, most probably Squalicorax kaupi. Based on the minute size of the included vertebrae, with the largest 4.5 mm long, the turtle must have been very small and likely newly hatched. Assuming the selachian producing the specimen was a marine or estuarine species, this coprolite specimen indicates that the shark was feeding in or proximal to a fluvial environment, as observed in modern species of Carcharhinus. Given the small size of the coprolite, the shark was likely also small, suggesting that a juvenile Late Cretaceous shark was feeding far upstream, perhaps near its pupping area.

Theropod Tooth from the Upper Cretaceous Himenoura Group in the Koshikijima Islands, Southwestern Japan

Abstract. A theropod tooth found in the Upper Cretaceous Himenoura Group in the Koshikijima Islands, Kagoshima Prefecture, is described. Recent paleontological work in the region suggests a middle Campanian age for the specimen. Lacking a feature diagnostic of any specific theropod clade, this specimen is considered merely as Theropoda incertae sedis. The present finding confirms the potential of the Himenoura Group as a new source of information on the diversity of Theropoda during the Campanian.

Upper Cretaceous volcanoclastic-sedimentary formations in the Timok Eruptive Area (eastern Serbia): new biostratigraphic data from planktonic foraminifera

Upper Cretaceous volcanoclastic-sedimentary formations in the Timok Eruptive Area (eastern Serbia): new biostratigraphic data from planktonic foraminifera The biostratigraphy of the Upper Cretaceous volcanoclastic-sedimentary formations cropping out in the Timok Eruptive Area of the eastern Serbian Carpatho-Balkanides is presented. Four lithostratigraphic units of formation rank are recognized in the Timok area: Stublica Clastics (Upper Albian/Cenomanian), Oštrelj (Lower Turonian/Santonian), Bor Clastics (Campanian/Maastrichtian) and Bukovo (Campanian/?Maastrichtian). Forty two species of planktonic foraminifera have been determined in the studied area. Eight planktonic foraminiferal zones of Middle Cenomanian through Middle Campanian age have been recognized. These are: Thalmanninella reicheli Interval Zone (Middle Cenomanian), Rotalipora cushmani Taxon Range Zone (Upper Cenomanian), Helvetoglobotruncana helvetica Taxon Range Zone (Lower Turonian), Marginotruncana sigali-Dicarinella primitiva Interval Zone (Upper Turonian to lowermost Coniacian), Dicarinella concavata Interval Zone (Lower Coniacian to lowermost Santonian), Dicarinella asymetrica Taxon Range Zone (Santonian), Globotruncanita elevata Interval Zone (Lower Campanian) and the Globotruncana ventricosa Interval Zone (Middle Campanian). The scarcity or lack of zonal species in the Lower Cenomanian and Upper Campanian/Maastrichtian strata prevents recognition of the nominal zones. The Upper Cretaceous planktonic foraminiferal zones from the Timok Eruptive Area are correlated with coeval zones from adjacent regions of Bulgaria and Romania and from other Tethyan regions.

Late Cretaceous calcareous nannofossil and planktonic foraminiferal bioevents of the shallow-marine carbonate platform in the Mitla Pass, west central Sinai, Egypt

The first detailed biostratigraphic analyses of the Coniacian–middle Campanian shallow-marine carbonate successions exposed in the Mitla Pass, west central Sinai, Egypt have revealed the stratigraphic distribution of diverse calcareous nannofossil and planktonic foraminiferal species. Thirty-six calcareous nannofossils and thirty-two planktonic foraminifera are identified, indicating a Coniacian to middle Campanian age and four Tethyan planktonic foraminiferal and five calcareous nannofossil zones. A comparison of these bioevents from different palaeolatitudes shows considerable variation in age. Three sequence boundaries coincident with the Turonian/Coniacian, Coniacian/Santonian and Santonian/Campanian stage boundaries are recognized. A fourth sequence boundary is marked by a major upper Campanian to early Ypresian (early Eocene) unconformity. These sequence boundaries are primarily related to regional tectonism associated with the Syrian Arc Fold System and secondarily to eustatic sea-level fluctuations.

Lithofacies, microfacies and depositional environments of Upper Cretaceous Oceanic red beds (Chuangde Formation) in southern Tibet

The Gyangze basin, located in southern Tibet, is one of the representative areas for Cretaceous Oceanic Red Beds (CORBs). We investigated and inter-correlated several new CORB outcrops in the western and southeastern part of the Gyangze area in addition to the previously described Chuangde section. The CORBs in the Gyangze basin mainly consist of shales, thin-bedded marls, re-sedimented limestones and clasts supported conglomerates-breccias. Planktonic foraminifers in the carbonate rocks within CORBs belong to the Globotruncana ventricosa and Globotruncanita calcarata zones, indicative of middle Campanian age. The facies assemblages in the different sections indicate that the depositional environments of CORBs range from outer base-of-slope apron to basin zones. Within carbonates, we observed microfacies types characteristic of basin, open deep shelf margin or toe-of-slope environments. Gravity transport resulted from the steepening of the sea floor in the Gyangze basin owing to subduction during the Campanian. Relatively oxic bottom water conditions prevailed below the toe-of-slope environment in the Gyangze basin during CORB deposition. However, the presence of gray clasts within a multicoloured matrix suggests less oxic conditions at shallower water depths within the basin.

Campanian Pseudosabinia from the Pučišća Formation on the island of Hvar (Adriatic Sea, Croatia)

The Upper Cretaceous carbonates on the Island of Hvar were deposited within the central Tethyan, intra-oceanic Adriatic carbonate platform (s. str). The Upper Cretaceous stratigraphy of the platform has been described in detail from the neighbouring island of Brac. Following the intra-platform deeper-water carbonate sedimentation of the Dol Formation, the Campanian Pucisca Formation (the Brač 'Marbles' unit) in the area of the town of Hvar are characterized by massive bioclastic rudist-bearing carbonates deposited in relatively deeper subtidal environments. Within the uppermost part of the Pucisca Formation we recognized massive rudist valves, characterized by a complex canaliferous inner shell structure, and determined them as Pseudosabinia klinghardti. The valves are embedded in massive, light-grey to white, mostly recrystalized peloidal-bioclastic packstone to rudstones, characterized in places by chalky appearance. The macrofossil association comprises various radiolitids, rare hippuritids, plagioptychids and inoceramid bivalves. Microfossil association includes index species of orbitoids and siderolitines. The range of the microfossils, along with results of strontium-isotope stratigraphy, indicate the latest Middle Campanian age of the Pseudosabinia horizon. Thus, it is the youngest horizon of the Pucisca Formation in the Adriatic carbonate platform reported to date.

Stratigraphy and sedimentology of the Upper Cretaceous (Campanian) Anacacho Limestone, Texas, USA

The Upper Cretaceous Anacacho Limestone is exposed in outcrops between the cities of San Antonio and Del Rio, Texas. A detailed study of four outcrops (Blanco Creek section, Sabinal River section, Seco Creek section, Hondo Creek section) shows that the Anacacho Limestone rests on the Upson Clay (which contains fauna of early Campanian age) and is overlain by the Corsicana Marl (which contains fauna of early Maastrichtian age). An unconformity within the Anacacho Limestone is used herein to separate the limestone into a lower member and an upper member. The lower Anacacho member contains fauna of early Campanian age, whereas the upper Anacacho member contains fauna of middle Campanian age. The lower Anacacho member consists predominantly of wackestones to packstones, which are overlain by packstones to grainstones capped by the unconformity. This unconformity is interpreted as a marine flooding surface, delineating a transition from carbonate grainstones deposited in shallow water (<30 m depth) to a chalk deposited in deeper water. Above the unconformity, the upper Anacacho member is characterized by a chalk, overlain by wackestones and packstones. The uppermost section of the Anacacho Limestone consists of packstones and grainstones with abundant and diverse fossils. Most of the Anacacho Limestone developed in relatively shallow water (<50 m depth) leeward of a large carbonate build-up (possibly a rudistid reef) that now comprises the Anacacho Mountains. The environment, however, was open to marine water throughout deposition of the Anacacho Limestone.

Bivalves and gastropods from the Middle Campanian Anacacho Limestone, south central Texas

The Anacacho Limestone was deposited during the Campanian and represents two depositional intervals, one of early Campanian and one of middle Campanian age. These two intervals correspond to periods of major eustatic sea level rise. This study focuses on the molluscan paleontology of the middle Campanian interval in the eastern part of the Anacacho exposure belt in Medina County, Texas. Molluscan assemblages in this area are indicative of inner to mid-shelf environments. No significant reef components are present. These eastern Anacacho deposits are interpreted to represent more offshore, deeper water environments than those to the southwest, where reef and lagoonal deposits have been reported.Analysis of the macrofossil components from these eastern localities has expanded the number of invertebrate species known from the Anacacho Limestone by nearly three-fold. This increase in diversity, based on a small amount of new work, suggests that many more taxa are yet to be identified, particularly in the western part of the exposure belt in Uvalde and Kinney Counties. This paper documents the bivalve and gastropod fauna, discussing and illustrating 24 bivalve taxa and 11 gastropod species. Two new bivalve species are named,Panopea anacachoensisnew species andSpondylus siccusnew species, and two potentially new gastropod species are identified but not named herein due to inadequate material. This paper expands the distribution of many eastern Gulf Coast and Atlantic Coast taxa westward into Texas and shows strong ties between the Anacacho fauna and that of the Campanian Tar Heel and Bladen Formations of the Black Creek Group in North Carolina. The taxonomic ties between these two areas probably reflect the thorough documentation of the North Carolina fauna, which is the best documented Campanian bivalve fauna in the Gulf or Atlantic Coast regions.

Regional Lithostratigraphy and Calcareous Nannofossil Biostratigraphy of the Arcola Limestone Member, Mooreville Chalk, of Eastern Mississippi and Alabama: ABSTRACT

ABSTRACT The Arcola Limestone, the upper member of the Mooreville Chalk of Mississippi and Alabama, is the most distinctive lithostratigraphic unit within the Mesozoic or Cenozoic outcrop belt of the eastern Gulf Coastal Plain area. Geographically, the Arcola extends from near Tupelo in northeastern Mississippi, about 365 km southeastward to near Downing in east-central Montgomery County, Alabama. The Arcola, which stratigraphically separates the Mooreville Chalk from the overlying and lithologically near identical Demopolis Chalk, varies in thickness from a few centimeters at its western and eastern termini to a maximum known thickness of 4.37 m at Hatchers Bluff along the Alabama River southwest of Selma, Dallas County, Alabama. Lithologically, the Arcola consists of from one to four beds of white to light-gray, bored and indurated calcisphere limestone, each varying from a few centimeters to a maximum of 0.8 m in thickness, separated by thin, moderately glauconitic and phosphatic, fossiliferous, quartzose silty chalky marl. In the shallow subsurface, the Arcola generally varies from 3 to 5 m in thickness and can be identified and mapped by its thin yet distinctive electric-log character. Further downdip, the electric-log marker as well as the characteristic light-color and indurated nature of the Arcola is no longer recognizable within the massive chalky marl of the Selma Group, yet the distinctive tiny calcispheres have been traced over a 30,000 km2 area of the Alabama Coastal Plain. Throughout its outcrop, as well as in numerous subsurface samples, the Arcola consistently lies within the uppermost few meters of the top of the lower Calculites ovalis Nannofossil Zone (CC19a) of middle Campanian age, thus representing the most geographically extensive time synchronous lithologic unit known within Mississippi or Alabama.

Stratigraphy and paleontology of Campanian and Eocene sediments, Cockburn Island, Antarctic Peninsula

Approximately 150 meters of fine-grained Campanian sediments and over 100 meters of fine- to medium-grained Eocene sands underlie Pliocene basalts and conglomerates on Cockburn Island, northeastern Antarctic Peninsula. The Campanian beds are part of the “Unnamed strata” of the Marambio Group and contain invertebrate and palynomorph fossils that predate the adjacent Seymour Island López de Bertodano succession. Rich palynomorph floras suggest a middle Campanian Age. Deposition was in low energy, shallow shelf environments. Invertebrate and palynomorph fossils, and lithology, all indicate correlation of the Eocene beds with the basal La Meseta Formation, members Telm 1 and lower Telm 2 of Seymour Island. The age of these beds is probably late early Eocene. The basal La meseta sands are marginal marine to shallow shelf sediments that fill a broad valley probably incised during latest Paleocene-earliest Eocene as a result of tectonism and sea-level lowstands.

Rock Mechanics of the Ekofisk Reservoir in the Evaluation of Subsidence

Mechanical properties have been determined for Ekofisk reservoir rock for use in subsidence simulation. Tests were to describe the mechanical properties of the Ekofisk chalk for reservoir conditions. The mechanisms and time dependence of chalk compaction and the effect of waterflooding on chalk strength were also examined.