Cretaceous Early

Figure 8 Various individual biomarkers have been used as age-dating compounds. A classic example of this is 18a(H)-01eanane, a compound associated with a higher plant input, more specifically an angiosperm source. Angiosperms generally are believed to have evolved at the end of the Cretaceous/Early Tertiary.

Figure 1 Phanerozoic carbon isotope record. Mass extinction intervals are shaded in gray (widths do not correspond to durations of inserts) (a) global marine carbonate record (after Veizer et al, 1999) (b) marine carbonate record from the Late Ordovician of the Baltic States (after Brenchley et al, 1994) (c) Late Devonian marine organic carbon record from New York State (after Murphy et al, 2000) (d) Late Permian marine carbonate record from China (after Bowring etal, 1998) (e) Late Triassic marine organic carbon record from Canada (after Ward etal, 2001) (f)Late Cretaceous-early Tertiary record of the carbon isotopic difference between fine fraction and benthic carbonate (left panel), between shallow dwelling planktonic and benthic foraminifera (open symbols, right panel) and between more deeper dwelling planktonic and benthic foraminifera (filled symbols, right panel) from the south Atlantic...

Retallack [2] computed relative acidification for the Brownie Butte boundary bed by using the impact bed as the parent material, and obtained a value of 0.054 meq cm. Since typical late Cretaceous/early Paleocene paleosols have acid consmnption rates of 0.01-0.02 meq cm yr" , this is evidence for enhanced leaching from the boundary bed relative to the impact bed. Because the boundary bed was emplaced -minutes to hours after tlie impact [33] and the bulk of the impact bed (including shocked quartz) was emplaced -hours to days after tlie impact bed, the boundary bed may have experienced somewhat greater acid deposition. This was true only if significant acid deposition occurred in tlie interval between boundary and impact bed emplacement. In the normal atmosphere rainout of acid in the troposphere occurs on timescales of days in the post-impact atmosphere rainout may have occurred soon after the unpack once the atmosphere cooled. Because of the uncertainties in such timescales and the possibility of different parent material compositions for the impact and boundary beds, we do not consider tlie relative acidification of the two beds further. 

Angiosperms became widespread during the Late Cretaceous-early Tertiary (Crane Lidgard 1989), but prior to that gymnosperms dominated, and their distinctive diterpane distributions have been traced back to Carboniferous rocks (Disnar Harouna 1994). With appropriate regional palynological calibration, the ratio... 

New flowers of Laurales from the Early Cretaceous (Early to Middle Albian) of... 

In this chapter, we present a newflower from the Early Cretaceous (Early-Middle Albian) Puddledock locality, Virginia, USA. We also formally describe a second lauralean floral structure from the same locality that was briefly considered in an earlier publication (Crane et al., 1994). Both taxa have features characteristic of extant Laurales, but provide new evidence of the floral diversity among lauralean lineages from the Early Cretaceous and thereby contribute to a better understanding of the early evolution of the order. 

Crane, P. R. and Friis, E. M. (2008). Carpestella lacunata gen. et sp. nov., a new basal angiosperm flower from the Early Cretaceous (Early to Middle... 

The Beppu hot springs are located at the eastern end of the Beppu-Shimabara Graben, Kyushu. The basement rocks are composed of Paleozoic crystalline schists and Cretaceous granitic rocks. Miocene to early Pleistocene andesitic rocks occur mainly in the southern part of the area, while lava domes of hornblende andesite which are younger than 100,000 years occur in the western part. 

Age of formation of Group B of Besshi-subtype are variable, early Cretaceous (Shimokawa), late Early Cretaceous to early Late Cretaceous (Makimine) and Triassic to Jurassic (Minenosawa, Kune). 

As a first example, we consider the diagenesis of clastic sandstones in the Gippsland basin, southeastern Australia, basing our model on the work of Harrison (1990). The Gippsland basin is the major offshore petroleum province in Australia. Oil production is from the Latrobe group, a fluvial to shallow marine sequence of Late Cretaceous to early Eocence age that partly fills a Mesozoic rift valley. 

Sorokin, A.A. Ponomarchuk, V.A. 2002. Umlekan-Ogodzha Early Cretaceous magmatic belt duration of magmatism. Geochimica et Cosmochimica Acta, 66, 15 , A728. 

The Late Cretaceous Pebble deposit is located within the southern part of the Late Jurassic to Early Cretaceous Kahiltna terrane, which is bounded to the southeast by the Peninsular terrane (Late Triassic to Late Jurassic) and to the northwest by flysch of the Kuskokwim Group (middle to Late Cretaceous) (Fig. 1). The southern Kahiltna terrane consists predominately of Jurassic to Cretaceous turbidite deposits and can be divided into two major lithologic units the Koksetna River sequence and the Chilikadrotna Greenstone (Wallace etal. 1989). The... 

Igneous activity that occurred between Late Cretaceous and Early Tertiary time shows a strong northeast-southwest trend, which is also evident in the regional aeromagnetic data. The aeromagnetic... 

Another type of analcime concentrations in sedimentary rocks are analcimolites. These are rocks composed almost entirely of granular, spherulitic analcime. Beds up to 1 to 2 m thick have been described in Jurassic formations of Georgia (9). Similar rocks have been found by Buryanova (10) among analcime tuffs and tuffaceous sandstones of early Carboniferous deposits of Tuva. Analcimolites are structurally similar to the rocks described by Vanderstappen and Verbeek (11) in Cretaceous and Jurassic rocks of the Congo. These authors assumed a sedimentary... 

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