Aptian

Cretaceous sedimentation started with the deposition of fresh-water limestones (Hauterivian) followed by successive layers of marine limestones (Barremian), marls (Aptian), marine limestones (Aptian), glauconitic sandstone (Aptian-Albian) and ended with a package of red detritic deposits. 

Fig. 9.8 Stratigraphic presentation of 813C values for organic material extracted from the Arundal clay formation, Maryland. Error bars reflect the standard deviation for three replicate analyses. The dashed line represents the boundary between the early and middle Aptian eras ( 125 to 112 megayears BP) established from the geological record. The gray arrow highlights the isotope shift of interest (Reprinted from Jahren, A. H. et al., Earth Planet. Sci. Lett. 236, 691, (2005), Copyright 2005, with permission from Elsevier)...

In 1969 V. Likholetnikov together with A.Vasserman [5,6] identified the so-called trap types in Kolkheti central and eastern parts in Bajocian, Bathanian, Neocomian-Aptian, Cenomanian, Turonian-Paleocene sediments and also natural reservoirs - in Upper Cretaceous and Paleocene sediments. 

Aptian-Albian (121-99 Ma) Extensive world-wide deposits Ontong Java other Pacific plateaus, Kerguelen... 

Bralower T. J., Sliter W. V., Arthur T. J., Lekie R. M., Allard D. J., and Schlanger S. O. (1993) Dysoxic/anoxic events in the Aptian-Albian (Early Cretaceous). In The Mesozoic Pacific Geology, Tectonics, and Volcanism, American Geophysical Union Monograph 77 (eds. M. S. Pringle, W. W. Sager, W. V. Sliter, and S. Stein), pp. 5-37. 

Tsekhovskii, Yu. G., Shchipakina, I.G. Khramtsov, I.N. (1995). Lateritic eluvium and its redeposition products as indicators of Aptian-Turonian climate. Stratigraphy and Geological Correlation 3, 285-294. 

Carbonate cements either indirectly enhance or deteriorate the reservoir properties of sandstones. Enhancement of reservoir properties occurs when (i) appreciable volumes of carbonate cements are dissolved, causing the formation of secondary porosity and (ii) small amounts of carbonate cement are evenly distributed in the sandstones to support the overburden weight and prevent the collapse of framework grains and consequent elimination of primary porosity. Souza et al. (1995) demonstrated that a few per cent of dolomite cement is sufficient to prevent the collapse of Aptian reservoir sandstones from Brazil despite the high content of ductile lithic fragments. 

Cooper basin sediments consist of glaciofluvial, fluvio-lacustrine and deltaic elastics (Fig. 2) (Bat-tersby, 1976 Thornton, 1979). The Jurassic section of the Eromanga basin sequence was deposited in an intercratonic basin sag, and is made up of non-marine elastics deposited under fluvial, deltaic and lacustrine conditions. The Early Cretaceous Murta Member to Cadna-Owie Formation (Fig. 2) show deposition changing from lacustrine to marine, with marine conditions prevailing from the Aptian until the Upper Albian, when a return to paralic and fluvio-lacustrine conditions is indicated (Senior et al., 1978 Armstrong Barr, 1986). 

Fig. 3. Generalized stratigraphy for the Dampier sub-basin. Major seismic markers are indicated MUC, Callovian-Oxfordian main rift or breakup unconformity K, near top Angel Formation KA, near top Aptian unconformity. Modified from Kopsen McGann (1985).

Moss, S. Tucker, M.E. (1995) Diagenesis of Barremian-Aptian platform carbonates (the Urgonian Limestone Formation of SE France) near-surface and shallow-burial diagenesis. Sedimentology, 42, 853-874. 

Aptian porcellanite from the west-central Pacific. Org. Geochem., 35 181-188. 

Dumitrescu, M. and Brassell, S.C., 2005. Biogeochemical assessment of sources of organic matter and paleoproductivity during the Early Aptian Oceanic Anoxic Event at Shatsky Rise, ODP Leg 198. Org. Geochem., 36 1002-1022. 

The Middle Jurassic and younger section on the stable Saharan Platform is dominated by relatively thin lagoonal dolomites, evaporates, and shales. Cretaceous sediments consist of alternating evaporates, limestones, dolomites, and thin layers of sandstone. Aptian-Albian nearshore carbonate facies are oU-bearing in Tunisia. Tertiary sedimentation is particularly present in Tunisia and farther over a wide scale of thickness (up to 7000 m). These sediments occvn from the Paleocene to the Pliocene in the east, and... 

The majority of the oils in the southern Paleozoic province were formed during the Paleozoic when burial of the source rocks exceeded 2-3 km. However, the Paleozoic traps were destroyed by the Hercynian erosion and the hydrocarbons then were able to dissipate. During the Mesozoic, throughout the subsidence of the northern and northeastern parts of the platform, the burial depths again reached the conditions necessary for the generation of hydro carbons. During the Cretaceous (post-Aptian) the depth of burial of the source rocks reached values of about 3 km which favoured mainly the formation of gas. 

Doyle, J. A. (1992). Revised palynological correlations of the lower Potomac Group (USA) and the Cocobeach sequence of Gabon (Barremian-Aptian). Cretaceous Research, 13,337-349. 

ANITA grade, 10, 89, 90, 100, 105, 106 Annonaceae, 102, 107, 148 anthophyte clade, 31 anthophyte taxa. See anthophyte clade Antirrhinum majus, 127 Aphandra, 161, 165 Apiaceae, 145 Aptian Late, 51 Aquilegia, 127 Arabidopsis, 15,146,148 thaliana, 127,177,272 Araceae, 110 Araliaceae, 128,232, 274 Araripia florifera, 279 Araucaria... 

Likewise reallocated, the unmistakable, spinose Acanthothirididae comprise two subfamilies, differing mainly in reduction of septum/septalium and details of their crura. The Aalenian to Tithonian Acanthothiridinae and the Aalenian to Aptian Acanthorhynchiinae. Pliensbachian precursors with nodose ribs seem more akin to the latter, yet might be ancestral to either. 

Towards the end of the early Cretaceous, two more subfamilies branched off the main tetrarhynchiine stem the Albian to Maastrichtian Viarhynchiinae (subsphaerical, uniplicate, densely costate, with crura transitional between canaliform and raduliform) and the Aptian to Maastrichtian Cretirhynchiinae (dorsibiconvex, finely and densely costellate, with subrectangular uniplication and distally concave raduliform crura). 

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