Cretaceous-Lower Tertiary Research Articles

Formation Mechanisms of Some Features in Siliceous Upper Cretaceous-Lower Tertiary Beds of Jordan-Undulations, Geodes, Boudinages

Formation Mechanisms of Some Features in Siliceous Upper Cretaceous-Lower Tertiary Beds of Jordan-Undulations, Geodes, Boudinages

Geochemical and Pb-Sr-Nd Isotopic Constraints Indicating an Enriched-Mantle Source for Late Cretaceous to Early Tertiary Volcanism, Central Anatolia, Turkey

Bulk-rock major, trace, and REE geochemistry and Pb-Sr-Nd isotopic compositions identify mantle sources involved in the genesis of volcanic rocks of the Upper Cretaceous-Lower Tertiary Ulukişla Formation, Çamard-Ulukişla Basin, Nigde Province, central Anatolia. Incompatible trace-element patterns exhibit a large Nb-Ta trough and strong enrichment of LILE such as Ba, Th and U, and LREE, which indicate a subduction-zone signature. Trace-element ratios are compatible with a subcontinental lithospheric source. Isotopic data demonstrate the presence of an EMII-like protolith (87Sr/86Sr = 0.707242-0.707582, 143Nd/144Nd = 0.512336-0.512390, 206Pb/204Pb = 18.70-18.917, 207Pb/204Pb = 15.716-15.796, 208Pb/204Pb = 39.157-39.45). These geochemical and isotopic data indicate the derivation of the studied volcanic rocks from an enriched subcontinental mantle source, modified by earlier subduction events. This petrogenetic conclusion is compatible with a geodynamic setting of post-collisional extension for the Çamard-Ulukişla Basin.

Contribution to the stratigraphy and facies analysis of the Upper Cretaceous-Lower Tertiary in northern Egypt

Contribution to the stratigraphy and facies analysis of the Upper Cretaceous-Lower Tertiary in northern Egypt

Valleys and Channels in the Upper Cretaceous-Lower Tertiary Succession, Northeastern Offshore Canning Basin, Australia

During detailed interpretation of seismic survey JNOC88 and some AGSO lines in the northeastern part of the Offshore Canning Basin (Offshore Fitzroy graben and part of the Rowley sub-basin), different scales of valleys and channels in the Albian to Palaeocene succession were noted. The sediments in the area of valley/channel development are dominantly calcilutite, marl, clay, silt, and fine sand deposited in shelf-to-slope water depths. The most evident valleys are associated with the Upper Cretaceous seismic event C6-2 and the Base Tertiary seismic event C13-1, with dominant north-south and northeast trends that are different from the northwest dip of the paleo-slope and -shelf. Small channels developed between C6-2 and C13-1 with an estimated northwest trend. We classify these channels and valleys into four categories: Type 1 to 3 valleys and Type 1 channels according to their scale, morphology, and related geological processes. Among them, Type 1 and Type 2 valleys are associated with the low point of the third-order global sea level curve, whereas the smaller-scale Type 1 channels seem to be associated with flooding surfaces. We suggest that submarine erosion by bottom current, contour current, or slumping formed the Type 1 valley, and similar processes in shallow water formed the Type 2 valley. The Type 3 valley is regarded as a valley cut into a lowstand fan.

ABSTRACT: Sequence Stratigraphic Framework of a Shelfal Siliciclastic Succession in an Upper Cretaceous-Lower Tertiary Salt Diapir Influenced Basin, La Popa Basin, Northeastern Mexico

La Popa Basin, Nuevo Leon, Mexico, is a salt influenced foreland basin with excellent exposures around several salt stalks, a 25 km salt wall and syndiapiric strata. The Delgado Sandstone Tongue, Potrerillos Formation is a shelfal sandstone/siltstone deposited during diapir growth in a complex, wave-dominated, eastward-prograding deltaic depositional system. Typical parasequences comprise offshore shale overlain by lower to upper shoreface sandstone. The Delgado Sandstone contains a lower, progradational parasequence set as part of a highstand system tract that is part of the underlying Middle Siltstone Member of the Potrerillos Formation and an upper retrogradational set that is part of a transgressive system tract that persists into the Upper Mudstone Member. The two system tracts are separated by an erosional sequence boundary that incises up to 10 m of underlying strata and locally preserves a lowstand system tract within incised valleys. Sequence stratigraphic correlation of 30 measured sections documents that: 1) strata proximal to El Gordo salt stock and La Popa salt wall show depositional thinning within a radius of 1 km, higher-energy and shallower-water lithofacies, and a difference in stratal stacking patterns toward the diapirs; and 2) strata around El Papalote salt stock exhibit thinning within a radius of 0.3 km, no change in lithofacies approaching the diapir, and similar stacking patterns on both flanks. These data suggest that the salt bodies had different bathymetric expressions during deposition of the Delgado Sandstone and may have had different uplift styles and/or rates.

Sandstone wedges of the Cretaceous-Lower Tertiary Kangerlussuaq Basin, East Greenland – outcrop analogues to the offshore North Atlantic

The Kangerlussuaq Basin is situated in southern East Greenland (68°30′N). The exposed 1 km thick sedimentary succession records a mid-Cretaceous to Tertiary basin history of Late Aptian–Albian transgression, Late Cretaceous–Early Paleocene highstand and mid-Paleocene uplift and erosion. The sediments are overlain by Upper Paleocene volcaniclastics, pyroclastics and flood basalts associated with continental break-up. Tertiary uplift and erosion has exposed the basin fill and it now represents one of the few outcrop analogues to the offshore Cretaceous-Tertiary sedimentary basins along the deep water margins of the North Atlantic. Three major sandstone-dominated intervals are identified in the succession: (1) mid-Cretaceous fluvio–estuarine sandstones; (2) Lower Paleocene submarine fan sandstones; and (3) mid-Paleocene fluvial and deltaic sandstones and conglomerates. The originally excellent reservoir properties of the sandstone bodies have been strongly modified by more than 4 km of burial and local high heat flux. Mechanical compaction, quartz precipitation, calcite cementation and illitization are the main porosity and permeability reducing agents in the rock sequence. The three major episodes of sandstone deposition were related to initial transgression and later relative sea-level falls and may help prediction of stratigraphic intervals with possible reservoir units in the undrilled offshore basins of the northern North Atlantic. The occurrence of mid-Paleocene proximal fluvial facies, thus suggests sediment bypass and deposition of coarse-grained clastics in the offshore areas southeast of Greenland and around the Faeroe Islands.

Kaolin cements in limestones; potential indicators of organic-rich pore waters during diagenesis

ABSTRACT Kaolin (dickite and/or kaolinite) cement occurs locally in the Chalk Group (Upper Cretaceous-Lower Tertiary) in the North Sea and the Derbyhaven Beds (Lower Carboniferous) on the Isle of Man, United Kingdom. Stable-isotope and petrographic data indicate that the kaolin cements in both the Chalk Group and Derbyhaven Beds precipitated during late diagenesis in either marine or modified marine pore waters. Kaolin cements in both formations are associated with hydrocarbons, which suggests that organic complexing of aluminum may be responsible for precipitation of kaolin cement. Published experimental studies have demonstrated that the mobility of aluminum is greatly increased by complexing with organic acids. In such systems aluminum would be released and made available for clay-mineral precipitation when the organo-aluminum complexes are destabilized. Increased whole-rock 13C values in Chalk Group limestones from the Eldfisk Field, where kaolin cement was widespread, provides corroborating evidence for the late diagenetic decarboxylation of organic acids, which would have released complexed aluminum. The presence of kaolin cement may thus be an indicator of the former presence of organic-rich pore fluids in limestones and provide an additional tool for determination of the pore-water history of limestones and sedimentary basins.

Sequence Stratigraphic Interpretation of an Upper Cretaceous-Lower Tertiary Carbonate Base-Of-Slope Succession: Gran Sasso d'Italia (Italy): ABSTRACTS

Sequence Stratigraphic Interpretation of an Upper Cretaceous-Lower Tertiary Carbonate Base-Of-Slope Succession: Gran Sasso d'Italia (Italy): ABSTRACTS

The genus Angulogavelinella Hofker, 1957, and its species (Foraminiferida, Rotaliina, Upper Cretaceous-lower Tertiary)

The genus Angulogavelinella Hofker, 1957, and its species (Foraminiferida, Rotaliina, Upper Cretaceous-lower Tertiary)

The ophiolites of northeast India — a subduction zone ophiolite complex of the Indo-Burman orogenic belt

The ophiolites of northeast India are rootless blocks of various dimensions, floating in a matrix which belongs to the upper Cretaceous-Lower Tertiary Disang Group. They consist of diverse igneous, sedimentary and metamorphic rocks, of which ultramafics are the main component. They do not constitute a continuous sheet but are made up of units haphazardly juxtaposed along faults or they consist of lensoid slices interbedded with Disang Group rocks. The ultramafics are interpreted as slices of oceanic crust and upper mantle obducted onto the Indian continental margin. Associated blue schist is indicative of subduction zone tectonics. The occurrences of ultramafics showing intrusive contacts and the presence of intermediate — acid volcanics suggest an island arc — continent type of collision along the Benioff Zone coincident with the ophiolite belt. The tectonic history of the Indo-Burman orogenic belt can be tentatively summarised as follows: (1) Introduction of the subduction zone during Cretaceous times; obduction of oceanic crust and upper mantle and intermixing with deep oceanic sediments. (2) Deposition of the Disang sediments. Formation of an island arc separating the sedimentary basin into eastern and western sub-basins. The Barail sediments were deposited in both basins. The formation of the island arc was accompanied by plutonism and volcanism and by deformation and low grade metamorphism of the lower Disang sediments. (3) Gradual shallowing of the basin consequent upon the collision of the island arc with the easterly subducted India plate. (4) Continent-continent collision and rotation of the down-basin normal faults into low angle reverse faults (thrusts) along which the thrust sheets were piled up. The frontal areas of the thrust sheets were asymmetrically folded. This was followed by asymmetrical folding of the rocks of the foreland areas. (5) Formation of gravity faults and conjugate sets of strike-slip faults in the orogen and the foreland areas. The structures associated with the ophiolite belt are attributed first to the collision of the easterly subducting India plate with an island arc and subsequently with the Burma plate.

Back-thrusting in accretionary prisms: microtectonic evidence from the Cretaceous-Lower Tertiary Shimanto belt of southwest Japan

Deformation styles of the Cretaceous-Tertiary Shimanto belt of southwest Japan have been examined in the eastern Kyushu and Kanto mountains. An early ductile deformation, which affects only the basal part of the Cretaceous formations, predates a widespread south-verging brittle deformation. The ductile deformation, which occurred between Lower Cretaceous and Lowermost Eocene time, is characterized by two conspicuous microstructures: a cleavage ( S1) and a stretching lineation ( L1). The L1 trend is transverse to the belt, averaging north-south. Strain analysis reveals a non-coaxial deformation regime related to synmetamorphic shearing directed from south to north. Such a landward vergence is thought to reflect back-thrusting at the rear of a Cretaceous accretionary prism formed along the SW margin of Japan.

Depositional sequences of the Malargüe Group (Upper Cretaceous-lower Tertiary), Neuquén Basin, Argentina

Data from 28 surface sections and oil industry boreholes were used in a regional sequence stratigraphic and sedimentologic study of the Campanian-Paleocene Malargüe Group. Understanding these 800-m-thick deposits is the key to unraveling the geotectonic regime which preceded Cenozoic magmatism and tectogenesis in the Central Andes of Argentina and Chile. Rocks of the Malargüe Group were deposited within a relatively narrow back-arc setting with a less than 120-km-wide seaway located between the magmatic arc in Chile and the more stable foreland of Central Argentina. Sediments include clastics, carbonates, and evaporites with occasional pyroclastics. The depositional setting ranged from continental to fully marine; most marginal-marine depositional belts were significantly influenced by tidal action. Sequence stratigraphic analysis shows that the Campanian-Paleocene record was not continuous, but a stack of eight separate depositional events related to third-order eustatic oscillations. Reconstruction of successive paleogeographies reveal an easterly migration of the depocenter, emplacement of magmatically derived material in the adjacent arc region. According to this interpretation, large scale Andean shortening and tectogenesis in the studied region, would not have occurred before late Oligocene.

Reinterpretation of Structural Geology of Northern Animas Mountains, Hidalgo County, New Mexico: ABSTRACT

The Animas Mountains are a north-south-trending range in south-central Hidalgo County, New Mexico. Previous publication on the geology of the northern Animas Mountains includes a reconnaissance map by Zeller and more detailed geologic mapping by Soule. Nearly 1000 m of Paleozoic marine and several thousand meters of Cretaceous clastic sedimentary rocks are exposed in the northern Animas Mountains. Intrusive rocks include Precambrian granite; Laramide stocks, dikes, and sills of quartz monzonite and quartz latite; and post-Laramide dikes of rhyolite and small vitrophyre intrusions. Previous structural interpretations of the northern Animas Mountains involved large-scale overthrusting and included this area in the Cordilleran overthrust belt. The authors believe the previous work misidentified parts of the Bliss (Precambrian), Mojado (Lower Cretaceous), and Ringbone (Upper Cretaceous-lower Tertiary) formations. They also suggest an alternative relationship of the Ringbone formation (Upper Cretaceous-lower Tertiary) to Laramide structures in several southwestern New Mexico mountain ranges previously included in the Cordilleran overthrust belt. This study includes a detailed analysis of the stratigraphy and structure, which also suggests an alternative model.

Source Rock Potential of Upper Cretaceous-Lower Tertiary (Maestrichtian-Danian) Moreno Formation, West-Central San Joaquin Valley, California: ABSTRACT

The Moreno Formation represents a base-of-slope to shelf-edge sedimentary sequence deposited along the central California continental margin during the late Maestrichtian to Danian (about 69-63 Ma). The formation consists of shales, mudstones, and siltstones with irregularly interbedded sandstones. The Marca Shale member of the Moreno Formation is particularly attractive as a potential petroleum source rock. The Marca contains sedimentologic, faunal, and geochemical evidence suggesting that it represents an anoxic depositional facies within the upper Moreno Formation. Submillimeter-scale depositional laminations are well preserved within the siliceous shale and diatomite of the Marca. Benthic foraminiferal biofacies are strikingly similar in patterns of abundance, dominance, and morphology to those found in Tertiary and Holocene sediments known or inferred to have been deposited under anoxic conditions. Also, total organic carbon (TOC) is as much as 7.25 wt.%. Laminated sediments contain kerogens of marine origin (Type II), whereas adjacent massive sediments contain organic matter dominated by kerogens of terrestrial origin (Type III). Data derived from this study indicate that the Moreno Formation has a significantly greater potential as a source of hydrocarbons than heretofore recognized. Rock-Eval pyrolysis and vitrinite reflectance data derived from core samples from a well near Coalinga show that the Marca shalemore » is marginally mature at relatively shallow depths. To the northeast, the Moreno is more deeply buried beneath late Tertiary and Quaternary basin-fill sediments, and has probably reached generative levels of maturity. Sands within the Moreno Formation are productive in at least two small fields in the western San Joaquin Valley. Thus, the Cretaceous of the San Joaquin basin may represent an exploration frontier in an otherwise mature basin.« less

Palaeomagnetism of Upper Cretaceous--Lower Tertiary igneous rocks from Central Argentina

Summary. From nine Upper Cretaceous—Lower Tertiary (85 ± 5–66 ± 5 Ma) volcanic hills in Central Argentina (33°S, 65°W), 26 hand samples were collected yielding a palaeomagnetic pole at 45°E 70°s (A95= 12.1°; k= 13.6; N = 12) after AC cleaning. Three sites show normal and nine reversed polarity. This pole is close to the pole for the late Cretaceous (69 Ma) Andacolo Series.

Cretaceous-Lower Tertiary Depositional Relations, Northeastern Alaska: ABSTRACT

Analysis of depositional environments and new paleontologic data indicate the need for a revised interpretation of Cretaceous and lower Tertiary stratigraphy in northeastern Alaska. A revision is important to the understanding of these rocks in unexplored areas to the north. In the Sadlerochit Mountains area, the late Neocomian transgressive Kemik Sandstone Member and pebble shale unit of the Kongakut Formation unconformably overlie Jurassic and Triassic rocks. The unconformity, which is present throughout northernmost Alaska, apparently grades to a conformable shelf sequence to the south. In the Sadlerochit Mountains area, Upper Cretaceous organic-rich shale and bentonite of Figure the Seabee Formation overlie the pebble shale unit; the intervening Aptian and Albian strata are either absent by nondeposition or are a thin, condensed section. Subsequent deposits of Late Cretaceous and early Tertiary(?) turbidites and shale were probably derived from east-northeasterly prograding deltas that are exposed west of the Canning River. Cretaceous strata in the Sadlerochit Mountains area are about 700 m thick and contain no erosional unconformities. The comparatively thin section is attributed to the area being high (although still in deep water) relative to the Colville basin axis to the south, which was a sediment trap. End_of_Article - Last_Page 608------------

Igneous history of the Andean Cordillera and Patagonian plateau around latitude 46°S

From the Middle Jurassic onwards persistent igneous activity in the southern Andes around 46 °S was controlled by easterly dipping subduction along the Pacific margin. Cogenetic plutonic rocks belonging to the Patagonian batholith, and calc-alkaline volcanics ranging from basaltic andesites to rhyolitic tuffs and ignimbrites are the principal products. Erosion of the primary volcanics has led at various times to the development of thick volcaniclastic sequences, for example in the Cretaceous-Lower Tertiary Divisadero formation. The Coyhaique region marks the northerly extension of a narrow back-arc basin in which the marine Neocomian successions accumulated. Volcaniclastics from the island arc, which presumably lay to the west, are intercalated with the sediments. Although the marine basin was short-lived a mildly extensional back-arc regime may have existed through much of Mesozoic-Recent times. Widespread basalt-rhyolite volcanism on the eastern side of the cordillera seems to have been associated with this tectonic environment. Remnants of the Patagonian basalt plateau at latitude 45-47 °S extend from the Argentine-Chile frontier to Lago Colhue Huapi. Four principal age and compositional groups have been distinguished in the lavas, (i) The oldest, which are about 80 Ma, occur in sections at Senguerr and Morro Negro. They are almost exclusively tholeiitic, but show some calc-alkaline affinities and resemble in other respects basalts from marginal basins, (ii) The second group (57-43 Ma) occur in the lower part of the Chile Chico section with a compositional spread from olivine tholeiites through alkali basalts to one occurrence of a basanite. (iii) The upper part of the main plateau sequence, where the flows are in the range 25-9 Ma, are dominantly of alkali basalt composition, (iv) Post-plateau flows from small cinder cones on the surface of the plateau range in age from ca. 4 Ma to 0.2 Ma or less. They are mostly highly undersaturated basanites, with occasional leucite basanites, enriched in incompatible elements. A few of the earlier tholeiites with calc-alkali traits may have been closely associated with subduction or marginal basin processes. The younger lavas are more alkalic intraplate types generated in the remote back-arc extensional zone.

Phosphatic and glauconitic sediments

A meeting on ‘Phosphatic and Glauconitic Sediments‘; is particularly appropriate in view of the considerable but often widely scattered literature, both published and unpublished, that has become available on this subject in recent years. Phosphatic and glauconitic sediments are those in which the calcium phosphate mineral, francolite, a variety of apatite and the hydrated potassium-iron silicate, glauconite, are prominent constituents. As such they have intrigued geologists for many years, particularly in connection with the nature of the chemical reactions responsible for their formation and the relative importance of individual parameters controlling these reactions. These sediments are widely distributed in the geological column, particularly in strata of Cambrian, Cretaceous–Lower Tertiary, and, in the case of phosphatic sediments, Permian and Miocene–Pliocene age. The association of apatite and glauconite in sediments has frequently been reported but integrated studies of the two minerals have, until recently, been comparatively few. These have shown that the minerals form by direct precipitation from sea water at the sediment/water interface, or diagenetically by interstitial replacement or replacement of pre-existing sediment. Phosphatic sediments are of great economic importance since they provide most of the raw material, known commercially by the imprecise term ‘phosphate rock’, for the manufacture of phosphate fertilizers and some phosphorus-based chemicals. For example, sedimentary formations accounted for c. 16 million tonnes ( c. 89%) of the total world output of c. 18 million tones of P in 1978. Although production is dominated by USA, the USSR and Morocco, there are other important producers of phosphate rock. In marked

Review of Upper Cretaceous-Lower Tertiary Stratigraphy in Central and Southern Egypt

The Upper Cretaceous-lower Tertiary sedimentary rocks in central and southern Egypt are characterized by gradual facies differentiation of three main types--Nile Valley, Garra-El Arbain, and Farafra. These facies are present in three different basins within the marginal trough on the northern flank of the African shield. Two main parvafacies are recognized, one in the Maestrichtian and the other in the Paleocene; the Nubia Sandstone in southern Egypt represents a heterochronous magnafacies correlatable with several rock units in central Egypt.

On the Morphology and Wall Structure of Tritaxia prramldata Reuss from the Late Cretaceous-Early Tertiary Deposits of Pondicherry, South India

Abstract Foraminiferal samples collected during a recent study of the Upper Cretaceous-Lower Tertiary deposits of Pondicherry area, South India, have yielded a large number of individuals of Tritaxia pyramidata Reuss. A detailed morphological and microwall structural study of these shells has been made. Such a study indicates a high degree of variation in the shell and apertural shapes. Contrary to the data provided by earlier workers, the wall structure in the specimens under examination, has revealed a two layered nature, the inner layer being formed of crystals of calcite. This new investigation demands reassessment of the taxonomic status of the form. Stratigraphically, Tritaxia pyramidata appears to be a high range species, being found distributed almost throughout the above formations.