A Survey on the condition of Micro Facies , Sedimentary Environment and the Cretaceous Deposits ( With Particular Reference to Central Iran )
Micro continent of central Iran is a part of middle Iran that is bounded with ophiolithic suture zones in Sistan, Naiin, Baft, Doruneh fault and Kashmar – Sabzevar ophiolites and is classifiable into Lut block, Shotori upland, Tabas subduction, Kalmard upland, Posht Badam block, Biaze Bardsir basin and Yazd block by means of long faults which are dextral strike – slip faults and have westwards inclination. In many regions of Iran, except to Zagros, in approximate boundary of early and late Cretaceous, it is observed evidences of tectonic events which are mainly as land generating and can be compared with worldwide Austrian event, in everywhere in Iran except to rare cases (east of Tehran and Yazd). Upper Cretaceous beds in Iran do not have identical facial characteristics and it seems that in contrast to equal sedimentary condition in early Cretaceous, sedimentary basins in upper Cretaceous have been separated from each other and special condition has been dominated in each basin. As a result of that, lithostratigraphic units except to Zagros and Kopet Dagh have not been named and or have local names in upper Cretaceous of Iran. This article is an overview of the condition of Micro-facies, sedimentary environment and the Cretaceous deposits in central Iran. [Mehran Arian, Hamideh Noroozpour. A Survey on the condition of Micro Facies, Sedimentary Environment and the Cretaceous Deposits (With Particular Reference to Central Iran) ). Journal of American Science 2011;7(6):915924]. (ISSN: 1545-1003). http://www.americanscience.org.
Amanz Gressly's role in founding modern stratigraphy
This paper discusses Amanz Gressly’s (1814-1865) fundamental contributions to stratigraphy in three areas: facies concepts and applications, stratigraphic correlation, and paleogeographic reconstruction. To facilitate access to his discoveries, we present an English translation of his paper (Gressly, 1838) on facies and stratigraphic correlation. We discuss excerpts from this translation which demonstrate that many of the fundamental principles of modern stratigraphy were understood and expressed by Gressly. We put this into the context of subsequent development and refinement of current stratigraphic principles. Gressly explained the genesis of sedimentary facies by processes operating in depositional environments. He demonstrated regular lateral facies transitions along beds which he interpreted as mosaics of environments along depositional profiles. He recognized the coincidence of particular fossil morphologies with particular sedimentological facies, and distinguished “facies fossils” from those which had time value and which were useful for biostratigraphy (“index” or “zone” fossils). He discussed the equivalency of vertical facies successions through a series of strata and lateral facies transitions along a bed, developing the same principle that later became known as Walther’s Law of the Correlation of Facies. He distinguished between the time value of strata and properties which reflect their genesis, and introduced specific terms to reflect this distinction. He used this understanding to show how stratigraphic successions should be correlated across different facies tracts. Gressly derived an internally consistent, logical and comprehensive definition of a new stratigraphic paradigm which was the basis for further developments and refinements. The five remaining principles of contemporary stratigraphic thought include: (a) the stratigraphic process-response system conserves mass; (b) sediment volumes are differentially partitioned into facies tracts within a space-time continuum as a consequence of mass conservation; (c) cycles of facies tract movements laterally (uphill and downhill) across the earth’s surface are directly linked to vertical facies successions, and are th e basis for high-resolution correlation of stratigraphic cycles; (d) stratigraphic base level is the clock of geologic time, and the reference frame for relating the energy of space formation with the energy of sediment transfer; and (e) facies differentiation is a byproduct of sediment volume partitioning.
A preliminary account of a new tyrannosauroid theropod from the Wessex Formation (Early Cretaceous) of southern England
Abstract A new genus and species of coelurosaurian theropod dinosaur from the Wessex Formation (Early Cretaceous, Barremian) of the Isle of Wight, England, is described and named. Distinctive characters of the premaxilla, its dentition, maxilla and nasals allow it to be diagnosed. The teeth in the premaxilla are D-shaped in cross-section and the nasals are fused. The hands are elongate and slender and the hindlimbs are gracile. Lack of element fusion elsewhere in the skeleton suggests that it is a subadult. Numerous character states are shared with tyrannosaurids but the new taxon appears to be excluded from the group that comprises aublysodontine and tyrannosaurine tyrannosaurids. We conclude that the taxon is a basal tyrannosauroid and as such it is one of the earliest and (with the exception of some teeth and an isolated ilium from Portugal) the first from Europe. Implications for tyrannosauroid biogeography and evolution are discussed. The animal was part of an unusual taphonomic assemblage in which some elements were partially articulated while others were scattered or broken.