Cretaceous Phosphates Research Articles

The Upper Cretaceous (Santonian-Maastrichtian) phosphate deposits in the west of the Neiva subbasin, Upper Magdalena Valley, Colombia

De tiempo atrás se conoce que los fosfatos económicamente explotables en Colombia se encuentran en sucesiones sedimentarias marinas del Cretácico Superior (Cathcart y Zambrano, 1967; Mojica, 1987; Zambrano y Mojica, 1990). En el occidente de la subcuenca de Neiva del Valle Superior del Magdalena (VSM), estos niveles están restringidos al intervalo Santoniano-Maastrichtiano, representado en las formaciones Lidita Inferior, Lidita Superior y Yaguará. Los fosfatos son lateralmente discontinuos y presentan variaciones faciales en distancias cortas. El análisis facial y las correlaciones estratigráficas permitieron inferir que las facies presentes en estas unidades representan un ambiente marino muy somero desde la zona de transición con el offshore hasta el shoreface superior, incluyendo condiciones de laggon para la Formación Aico. Posiblemente, la paleotopografía y la subsidencia diferencial han afectado la continuidad lateral y el espesor de las unidades litoestratigráficas del intervalo Santoniano-Maastrichtiano, y los eventos tectónicos posteriores han modificado la distribución espacial de los depósitos de fosfatos. La falla de La Plata (Chusma) divide la zona en cuestión en dos dominios estructurales: uno localizado en el occidente, en el bloque levantado, donde afloran las rocas más antiguas del basamento pre-Cretácico, y otro dominio localizado en el oriente, en el bloque hundido, donde aflora la secuencia sedimentaria cretácica-cuaternaria característica de la subcuenca de Neiva. En el bloque hundido se encuentran pliegues importantes, como el Sinclinal de Media Luna y el Anticlinal de San Francisco en el norte, el Anticlinal de La Guagua en la parte central, y el Anticlinal de La Hocha y el Sinclinal de El Vegón en el sur. Algunos de estos pliegues están truncados por fallas regionales inversas con componente de rumbo dextral, como las fallas de La Plata (Chusma), San Francisco y Betania.

First Record of a Tylosaurine Mosasaur from the Latest Cretaceous Phosphates of Morocco

The latest Cretaceous Phosphates of Morocco preserve the highest biodiversity of mosasaurid squamates anywhere in the world. Intensive sampling over the past century has uncovered at least ten genera and thirteen species from the mosasaur subgroups Halisauromorpha, Plioplatecarpinae, and Mosasaurinae. Notably missing from the assemblage are members of the macropredatory Tylosaurinae. The Tylosaurinae were globally rare in the Maastrichtian and their apparent absence has been previously explained by either collecting bias, ecological preference for deeper waters, or habitat restriction to higher paleolatitudes. Here, we describe a new tylosaurine mosasaurid, Hainosaurus boubker sp. nov., based on several partial skulls and isolated teeth originating from the Couche III layer of the Sidi Chennane Phosphate quarry near Oued Zem, Morocco. It is unique amongst tylosaurine mosasaurids in possessing blade-like teeth that are laterally compressed, encircled by enamel facets, and differentiated along the dental margin. The discovery of this new taxon in the Maastrichtian of Morocco is remarkable as it represents both the youngest species of Tylosaurinae and the first occurrence in North Africa.

An articulated pterosaur wing from the Upper Cretaceous (Maastrichtian) phosphates of Morocco

A new and articulated specimen of a pterosaur wing including the humerus, radius/ulna, parts of the carpus and metacarpus and a first wing phalanx from Maastrichtian phosphatic deposits of Morocco is assigned to Tethydraco regalis Longrich et al., 2018. Aspect of the humerus morphology, shape of the deltopectoral crest and ratios of the wing elements suggest that T. regalis is an azhdarchid rather than pteranodontian pterosaur, as originally proposed. A high abundance of azhdarchid remains in the open marine setting of the Moroccan phosphates casts doubt on suggestions that Azhdarchidae are largely terrestrial pterosaurs.

A new species of longirostrine plioplatecarpine mosasaur (Squamata: Mosasauridae) from the Late Cretaceous of Morocco, with a re-evaluation of the problematic taxon ‘Platecarpus’ ptychodon

The Upper Cretaceous phosphates of Morocco preserve one of the world’s most diverse assemblages of mosasaurs, reflecting the adaptive radiation of this clade during the Maastrichtian. Herein, we describe a new mosasaur from these deposits. Although the teeth of this specimen resemble those of ‘Platecarpus’ ptychodon, suggesting referral to this species, we re-examine and ultimately reject the fundamental validity of ‘P.’ ptychodon due to the non-diagnostic nature of its holotype and original diagnosis. We instead designate the new specimen as the holotype of a new genus and species, Gavialimimus almaghribensis, gen. et sp. nov. G. almaghribensis is characterized by a highly elongate snout, highly retracted nares and large supratemporal fenestrae, among other features. Phylogenetic analysis under multiple parsimony-based methods reveals novel substructure within the subfamily Plioplatecarpinae, consistently recovering a clade uniting the new species with Selmasaurus and the enigmatic Goronyosaurus. Synapomorphies of this clade include a highly constricted parietal, with Selmasaurus and Gavialimimus being further united by a broadly excavated medial surface of the quadrate suprastapedial process. The cranial morphology of G. almaghribensis also provides new insight into several aspects of mosasaur evolution and comparative anatomy, including adaptive radiation and niche partitioning in Moroccan marine palaeoecosystems. http://zoobank.org/urn:lsid:zoobank.org:pub:6896D6EE-2609-4917-A811-904B5AA7A8BB

Geochemistry of uranium and thorium in phosphate deposits at the Syrian coastal area (Al-Haffah and Al-Qaradaha) and their environmental impacts.

The aim of this research was to study the geochemistry of uranium and thorium in phosphate deposits in the upper Cretaceous phosphate deposits in the Syrian coastal area. The study covered three sites, namely Ain Al-Tenah, Ain Laylon, and Al-Mhalbeh. Petrographical study showed that phosphate deposits are of nodular type with micrit to microspaite cement, containing siliceous bone residues, and green grains of glauconite, which are increasing in abundance and volume in the south toward Al-Mhalbeh, reflecting the formation of phosphate in a shallow marine environment. In addition, uranium concentration varied between 3 and 112ppm in Ain Laylon, 4.2-17ppm in Ain Al-Tenah and 5-61ppm in Al-Mhalbeh. Thorium concentration varied between 0.2 and 7.5ppm in Ain Laylon, 0.3-1.4ppm in Ain Al-Tenah and 0.3-4.4ppm in Al-Mhalbeh. The average Th/U ratio in the collected samples was within the range 0.04-0.08 except for five samples which exceeded the value 0.1. Moreover, the 226Ra/238U ratios are lower than unity in all samples, while the 210Pb/238U ratios ranged between 0.4 and 1.2 and the 210Pb/226Ra ratios were found to be higher than unity. On the other hand, the impact of leaching and mobility of uranium and thorium from deposits to the surrounding agriculture fields in the area has been studied using the Radium Equivalent Activity Index (Raeq). The equivalent radium activity was 102Bqkg-1 in Ain Al-Tenah, 403 Bqkg-1 in Ain Laylon, 407 Bqkg-1 in Al-Mhalbeh and 749 Bqkg-1 in agricultural soil samples. However, the data reported in this study can be considered as a baseline data for the phosphate deposits at the coastal area.

Investigation for uranium dispersion adjacent to cretaceous phosphatic outcrops in Al-Nassrieh Basin, southern Palmyrides, Syria

A detailed radiometric survey including soil gas radon measurements and field gammaray survey, in accordance with geochemical and geological investigations were carried out in Al-Nassrieh Basin (central Syria), for the purpose of uranium exploration. Thirty-six samples were collected from various lithofacies of the survey area and analyzed by γ-ray spectrometric technique for determining the concentration values of major radioelements. The relationships between the concentrations of equivalent eU, eTh, and their ratios were examined in order to define their trend of variations and evaluate the degree of uranium remobilization and redistribution. Although the initial results indicate that uranium enrichment is mostly restricted to the Upper Cretaceous phosphate rocks, a considerable portion of uranium appeared to be leached out of the primary phosphatic source and dispersed in the adjacent recent sediments. Further, notable increases of radon level associated with relatively high values of uranium concentration and gamma count rates were found to be spatially correlated with the transition zone between the marine Paleogene and continental Neogene formations throughout the study basin. This observation demonstrates the importance of the concerned zone as a suitable geological environment for hosting probable uranium mineralization along a chemically reducing interface where surface water of terrestrial and marine origin mingled at depth and away from surficial conditions.

A strange new chelonioid turtle from the Latest Cretaceous Phosphates of Morocco

A new genus and species of huge marine turtle (superfamily Chelonioidea, epifamily Dermochelyoidae) is described from the Maastrichtian Phosphates of the Oulad Abdoun Basin of Morocco. A new type of feeding apparatus, adapted for a powerful crushing pattern, illustrates the noteworthy diversity of fossil vertebrates of the Maastrichtian-Ypresian Phosphates of Morocco. No other crushing cryptodire or bothremydid pleurodire has this morphology. During the Maastrichtian, the known crushing pattern of chelonioids was different, close to that of modern cheloniids, as illustrated in Morocco in the Maastrichtian Ganntour Basin and the Palaeogene Oulad Abdoun Basin. This new taxon exhibits unusual cranial characters (fusion of premaxillae associated with a backward and dorsal retraction of the naris, horizontal stretching of the dorsal meatus quadrati), that are shared only with another new turtle, known also from the same Maastrichtian Phosphates of Morocco.

A new mosasaurine from the Maastrichtian (Upper Cretaceous) phosphates of Morocco and its implications for mosasaurine systematics

ABSTRACT A new mosasaur, Eremiasaurus heterodontus, gen. et sp. nov., from the Maastrichtian phosphates of Morocco is described based on the basis of two specimens: one consisting of a nearly complete skull, vertebral column, and isolated appendicular elements, and the other a nearly complete skull with associated vertebral column. This new mosasaur exhibits a high degree of heterodonty and a large number of pygal vertebrae, the latter feature expressed to a greater degree only in Plotosaurus from the Maastrichtian of California. Analysis of a data matrix of 135 characters and 32 terminal taxa resulted in three equally most parsimonious trees, and recovered E. heterodontus as the sister taxon to Plotosaurini. A second analysis incorporating five species of the globidensine mosasaur Prognathodon recovered 252 most parsimonious trees. This second analysis also recovered E. heterodontus as the closest relative to the Plotosaurini, a position supported by the presence of an internarial bar keel, exclusion of the prefrontals from the narial borders, narial embayments in the frontal, and the presence of a quadrate ala groove. A change in the positions of several key character-state changes in the second analysis not only supports the exclusion of E. heterodontus from the globidensine mosasaurs, but also calls into question the monophyly of the Globidensini and the suite of quadrate and dental characters used to diagnose this group.

Paragenesis of upper cretaceous titanium-zirconium placers and phosphate mineralization in the southern East European Platform

Association of titanium-zirconium placers and phosphate mineralization in Upper Cretaceous rocks of the East European Platform is shown with the Tsentral’noe (Central) and Unecha deposits as example. This paragenesis is caused by interaction between the multicomponent placer ore (phosphate-rare metal) concentrations and mechanical-chemical differentiation that shows up periodically during the sub-aerial migration of sedimentary material. Clastic ore components were mainly derived from intermediate collectors, while the phosphate material was delivered by the phosphate-containing solutions and particulates in the chemical weathering crust. Such phosphorite-titanium-zirconium occurrences can also be detected in other regions, including areas with rare metal placers.

A review ofPachyvaranus crassispondylusArambourg, 1952, a pachyostotic marine squamate from the latest Cretaceous phosphates of Morocco and Syria

AbstractThe discovery of new specimens ofPachyvaranus crassispondylusArambourg, 1952 from the Maastrichtian phosphates of Morocco and Syria enables us to (1) redescribe in detail this poorly known varanoid lizard, (2) provide a more detailed diagnosis and (3) re-evaluate the systematic affinities of this taxon within squamates. The latter is placed in Pachyvaranidae nov., considered a new unranked clade of non-pythonomorph Varanoidea. The intense pachyosteosclerosis observed in the vertebrae and ribs suggests a primarily aquatic mode of life forPachyvaranus. This is in accordance with the sedimentological context (shallow marine environment). As for its palaeobiogeographical distribution,Pachyvaranusis a component of the marine reptile assemblages from the southern margin of the Mediterranean Tethys, around palaeolatitudes 20° N. The osteoderms previously referred to this taxon by Arambourg are reanalysed and assigned to a teleost fish.

Late Jurassic/Early Cretaceous phosphates of Nordvik, North Siberian Basin

Late Jurassic and Early Cretaceous calcite-rich phosphate (fluor/hydroxy apatite) concretions in the North Siberian basin (Nordvik) have been analysed. Their mineralogical and geochemical (major, trace and rare earth element) characteristics are presented in a sedimentological context. Low oxygen conditions prevailed along large parts of the seafloor of this wide epicontinental sea. In the Nordvik region this, in combination with slow and very fine-grained clastic sedimentation, and high algal production, resulted in the formation of phosphatic concretions. The concretions mainly consist of microcrystalline to ultracrystalline apatite and calcite, with traces of sphalerite, pyrite, kaolinite, quartz and albite. The clastic composition of the concretions is comparable with the surrounding Nordvik shales. Dysoxic–anoxic conditions in the last precipitating pore-water phases (early diagenetic) are reflected in enrichments in, for example, vanadium, uranium and the rare earth elements in the concretions.

The selachians’ faunas of the Moroccan phosphate deposits and the KT mass-extinctions

The Cretaceous and Tertiary phosphate deposits of Morocco which have a vertical thickness covering 25 My (Maastrichtian–Lower Lutetian), are well known for their rich fossil archives. The selachians' fish constitute the most abundant and varied vertebrate faunas. Analysis of the dynamics and patterns of extinctions and faunal renewals identified two significant episodes of high rates of extinction. A mass-extinctions event took place at the end of the Maastrichtian (Cretaceous–Tertiary boundary, KT) when more than 95% of species disappeared. The Lower Ypresian witnessed a second, selective, event which appears to have mainly affected sharks. Geochemical analysis may enlighten the environmental changes.

Late Jurassic/Early Cretaceous phosphates of Nordvik, North Siberian Basin

Late Jurassic and Early Cretaceous calcite-rich phosphate (fluor/hydroxy apatite) concretions in the North Siberian basin (Nordvik) have been analysed. Their mineralogical and geochemical (major, trace and rare earth element) characteristics are presented in a sedimentological context. Low oxygen conditions prevailed along large parts of the seafloor of this wide epicontinental sea. In the Nordvik region this, in combination with slow and very fine-grained clastic sedimentation, and high algal production, resulted in the formation of phosphatic concretions. The concretions mainly consist of microcrystalline to ultracrystalline apatite and calcite, with traces of sphalerite, pyrite, kaolinite, quartz and albite. The clastic composition of the concretions is comparable with the surrounding Nordvik shales. Dysoxic–anoxic conditions in the last precipitating pore-water phases (early diagenetic) are reflected in enrichments in, for example, vanadium, uranium and the rare earth elements in the concretions.

Authigenic dolomite cementation in the Upper Cretaceous Phosphate Formation, Western Desert, Egypt

The Upper Cretaceous Phosphate Formation in the Western Desert of Egypt displays a characteristic facies association that includes marine phosphorites interbedded with black shales and glauconitic sandstones. The upper part of the formation is characterized by the presence of thin phosphatic beds, which are filled-extensively-with disordered and non stoichiometric (mean MgCO 3 = 41.4 ± 0.34 mol%) authigenic dolomite cement. SEM and the back scattered images of these coarse crystalline dolomite cements reveal that they display planar euhedral crystal boundaries, polymodal crystal size distribution and variable inclusion pattern. The relatively low and wide ranged δ 18O (− 0.87 to − 4.15‰ VPDB) values of the dolomite cements coupled with their depleted Sr (mean = 187 ± 26 ppm) and high iron and manganese values (mean = 6851 ± 554 ppm and 11599 ± 229 ppm respectively) invoke that they were formed from mixed hypo-saline fluids within a mixing marine–meteoric zone probably during a low stand period at the vicinity of the Maastrichtian/Early Tertiary unconformity. Meanwhile, their negative δ 13C (− 1.31 to − 3.56‰ VPDB) values argue for a possible involvement of isotopically light carbon, derived from degradation of organic matter, during their precipitation.

Nature and geochemistry of surface sediments of the mangrove environment along the Egyptian Red Sea coast

Grain size and geochemical analyses have been carried out on 58 samples collected from different areas of mangrove environment of the Egyptian Red Sea coast. The texture characteristics of mangrove sediments show that the mean size decreases in sediments of coastal areas while increase in island sediments and the sediment type generally changes from sand to slightly gravelly muddy sand. The sediments are composed mainly of poorly sorted, negatively nearly symmetrical and leptokurtic fine sands. Cluster analysis showed that, distribution of gravel, sand and mud fractions is related to bottom facies and type of sediment source. Generally, sand fraction is the main category among the three constituents. Geochemically the factor controlling the carbonate content of studied sediments includes material supply of biogenic and terrigenous components. Therefore, sediments of Hamata area, km 17 south Safaga, Wadi El-Gemal Island and Abu-Minqar Island are terrigenous sediments, while sediments of km 37 north Quseir are highly carbonates. In general organic matter is higher in the mangrove sediments relative to adjacent areas. The high organic matter in the mangrove sediments is primarily due to the high supply from primary productivity, terrestrial and reworked sediments. Texture is the main controlling factor for the organic matter enrichment. Spatial variations in the phosphorus content in the different studied localities are related to the sources of phosphorus to the area. In comparison, cluster analysis indicates that phosphorus might be transported from terrestrial source to the sea through wadis draining the excavated Upper Cretaceous phosphate rocks. Also, the abundance of phosphorus content may be attributed to phosphatization of calcareous skeletons. Our observations provide knowledge on the physico-chemical effects and will be useful in the management and suitable development of the areas under study. In addition it represent database in the future.

Corrigendum to ‘Durophagous Mosasauridae (Squamata) from the Upper Cretaceous phosphates of Morocco, with the description of a new species of Globidens’

Corrigendum to ‘Durophagous Mosasauridae (Squamata) from the Upper Cretaceous phosphates of Morocco, with the description of a new species of <i>Globidens</i>’

Durophagous Mosasauridae (Squamata) from the Upper Cretaceous phosphates of Morocco, with description of a new species of Globidens

AbstractThree durophagous mosasaur species are represented by isolated teeth in the Upper Cretaceous (Maastrichtian) phosphatic beds of Morocco. Globidens phosphaticus nov. sp. is characterised mainly by a strong heterodonty, with mid-posterior teeth being bulbous, irregularly oval in crosssection, and having an inflated posterior surface, a large eccentric located and recurved apical nubbin, vertical sulci on medial and lateral faces, no carinae and an enamel surface covered by anastomosing ridges. Teeth of Prognathodon currii are broad and tall, straight cones, slightly swollen at the base, and with two serrated carinae. These two taxa have been collected from all the phosphatic series (lower to upper Maastrichtian) in the Ganntour Basin (Morocco). Globidens phosphaticus nov. sp. is probably also represented at other Maastrichtian phosphatic sites along the southern margin of the Mediterranean Tethys. Prognathodon currii was previously known only from the Upper Cretaceous phosphates of Negev. Of the third taxon, Carinodens belgicus, only a single tooth (now lost) is known from the Oulad Abdoun Basin (Morocco); this is low, swollen, laterally compressed and bicarinate with a large apical nubbin. Previous records of this species include Europe and Brazil.

A new species of Halisaurus. from the Late Cretaceous phosphates of Morocco, and the phylogenetical relationships of the Halisaurinae (Squamata: Mosasauridae)

A new species of the basal mosasaurid Halisaurus from the Late Cretaceous (Late Maastrichtian) of the Oulad Abdoun Phosphate Basin of Morocco is described on the basis of both cranial and postcranial remains. H. arambourgi sp. nov. is characterized by unique features of the nares, frontal, parietal, girdle and limb bones. A phylogenetical analysis supports the monophyletic status of Halisaurus; H. platyspondylus (Maastrichtian, New Jersey), H. ortliebi (Maastrichtian, Belgium) and H. arambourgi form an unresolved polytomy. This study does not support the attribution of ‘Halisaurus’sternbergii (Santonian, Kansas) to Halisaurus nor to any known genus. A new genus, Eonatator, is proposed for the reception of this species, Eonatator sternbergii comb. nov. The new taxon Halisaurinae (Halisaurus + Eonatator) is the sister-group of more advanced mosasaurids (Natantia). Halisaurines are defined by the shape of the lateral premaxilla–maxilla suture; an oblique contact plane between the parietal and the supratemporal; a preaxial ridge present on the distal two-thirds of the radius length; and tibia and fibula long and slender with slightly expanded extremities. © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society, 2005, 143, 447–472.

The first record of a sauropod dinosaur from the Late Cretaceous phosphates of Morocco

Sauropod dinosaur remains have been discovered recently in the Late Cretaceous (Maastrichtian) phosphatic deposits of the Oulad Abdoun Basin, near Khouribga (central Morocco). The material consists of right hindlimb bones (femur, tibia and fibula) from a small-sized individual. The marine associated fauna, mainly selachians, actinopterygians, turtles, mosasaurids and plesiosaurs, suggests a marine depositional environment, so that the dinosaur remains may be a remnant of a floating carcass. The femur exhibits a prominent lateral bulge on the proximal one-third, a diagnostic feature of Titanosauriformes. The Moroccan sauropod lacks synapomorphies of Titanosauria and less inclusive clades (i.e., distal tibia expanded transversely to twice mid-shaft breadth; femoral distal condyles angled dorsomedially relative to the shaft); therefore, it is here assigned to a basal titanosauriform as Titanosauriformes indet. This is the first sauropod reported from the Maastrichtian of Morocco and one of the few dinosaur records from the uppermost Cretaceous formations of northern Africa. This discovery confirms the wide geographical distribution of Titanosauriformes during the Late Cretaceous and supports their survival into the Late Maastrichtian of Africa.

Mosasaurus beaugei Arambourg, 1952 (Squamata, Mosasauridae) from the Late Cretaceous phosphates of Morocco

Mosasaurus beaugei Arambourg, 1952 was based on isolated teeth from the Maastrichtian phosphatic deposits of Morocco. The recent discovery of new material, including skull and mandibular remains, improves our knowledge of this species. M. beaugei shares the following synapomorphies with the genus Mosasaurus: large teeth bearing two prominent carinae and with asymmetrical labial and lingual surfaces, the labial one being flattened and strongly facetted and the lingual one being convex; premaxillae with a small pointed rostrum and dentary without rostrum; palatal elements closely united; coronoid with very large ventromedial process overlying the prearticular. M. beaugei is characterised by the following autapomorphies: 12-13 maxillary teeth; marginal teeth bearing 3-5 prisms on the labial surface and 8-9 on the lingual one; palatine with posterior border concave and perpendicular to the long axis of the skull; splenial visible laterally on half of the dentary ventral surface; coronoid with anterior wing well developed and bearing two notches. M. beaugei is only known to date in the Maastrichtian phosphates of Morocco.