Pétrologie et Géochimie des massifs du Tchabal Gangdaba-Hosséré Mana Paperback - 2015
by Itiga Zénon
From the publisher
Le magmatisme, comme ensemble de processus lis la gense, l'volution et la mise en place des magmas, est le trait gologique majeur de cette rgion du Nord-Cameroun. Le volcanisme cnozoque (34,40 24,82 Ma) du Tchabal Gangdaba est alcalin sodique et forme une bimodalit magmatique. Les volcanites mafiques (picrite, basanite) sont constitues d'olivine, clinopyroxne et oxydes Fe-Ti. Les volcanites felsiques (trachyte, rhyolite) renferment les feldspaths alcalins et la biotite. La squence mafique est le produit d'une cristallisation fractionne d'un magma de type HIMU (87Sr/86Srm = 0,7033). La squence felsique rsulte d'une contamination crustale (87Sr/86Srm = 0,7167-0,7207). Le complexe noprotrozoque (757,30 562,93 Ma) du Hossr Mana se compose surtout de synodiorite et granite qui renferment du feldspath alcalin, quartz, plagioclase, augite, hornblende, biotite et oxydes Fe-Ti. Le gabbro se distingue par des textures grenues pseudocumulatives et contient du plagioclase, amphibole, biotite et augite. Cette srie est calco-alcaline et sodique. La cristallisation fractionne a influenc la diffrenciation d'un magma d'origine mixte (87Sr/86Srm = 0,7058-0,7090).
Details
- Title Pétrologie et Géochimie des massifs du Tchabal Gangdaba-Hosséré Mana
- Author Itiga Zénon
- Binding Paperback
- Language ENG
- Publisher OmniScriptum
- Date 2015
- ISBN 9783838178790
Remote Content Loading...
Hang on… we’re fetching the requested page.
Book Conditions Explained
Biblio’s Book Conditions
-
As NewThe book is pristine and free of any defects, in the same condition as when it was first newly published.
-
Fine (F)A book in fine condition exhibits no flaws. A fine condition book closely approaches As New condition, but may lack the crispness of an uncirculated, unopened volume.
-
Near Fine (NrFine or NF)Almost perfect, but not quite fine. Any defect outside of shelf-wear should be noted.
-
Very Good (VG)A used book that does show some small signs of wear - but no tears - on either binding or paper. Very good items should not have writing or highlighting.
-
Good (G or Gd.)The average used and worn book that has all pages or leaves present. ‘Good’ items often include writing and highlighting and may be ex-library. Any defects should be noted. The oft-repeated aphorism in the book collecting world is “good isn’t very good.”
-
FairIt is best to assume that a “fair” book is in rough shape but still readable.
-
Poor (P)A book with significant wear and faults. A poor condition book can still make a good reading copy but is generally not collectible unless the item is very scarce. Any missing pages must be specifically noted.