نتایج جستجو برای: eocene alkaline rocks

تعداد نتایج: 68026  

2002
Mark L. McFarland Vincent A. Haby Larry A. Redmon David H. Bade

The minerals from which a soil is formed partly determine whether it is acid or alkaline. Soils formed from acidic rocks have a lower pH than those formed from basic rocks or alkaline parent material. Rainfall affects soil acidity development by leaching basic elements such as calcium, magnesium, potassium, and sodium from the soil profile, leaving the acidic elements: hydrogen, aluminum and ma...

2001
Grace Bianciardi

INTRODUCTION The rocks on the Greek island of Syros are part of a suite of high pressure metamorphic rocks which outcrop all across the Cyclades. There is a complex metamorphic history recorded in the rocks here, including a Cretaceous or Eocene high-pressure blueschist event and a Miocene, extension-related greenschist overprint. The Island of Syros is mostly composed of schists , which altern...

2011
Michele G. Bishop

Mature, synrift lacustrine shales of Eocene to Oligocene age and mature, late-rift coals and coaly shales of Oligocene to Miocene age are source rocks for oil and gas in two important petroleum systems of the onshore and offshore areas of the Northwest Java Basin. Biogenic gas and carbonate-sourced gas have also been identified. These hydrocarbons are trapped primarily in anticlines and fault b...

ژورنال: :پژوهش های دانش زمین 0
عیسی آزادی دانشجوی دکتری زمین شناسی، دانشکده علوم زمین، دانشگاه شهید بهشتی محمد رهگشای دانشیار دانشکده علوم زمین، دانشگاه شهید بهشتی سعید علیرضایی دانشیار دانشکده علوم زمین، دانشگاه شهید بهشتی محمد هاشم امامی دانشیار سازمان زمین شناسی و اکتشافات معدنی کشور

سنگ­های آتشفشانی با ترکیب تفریتی و فونوتفریتی با سن ائوسن بالایی در رشته کوه بزقوش، شمال غرب ایران گسترش قابل ملاحظه­ای دارند. این سنگ­های آتشفشانی هم به صورت گدازه­هایی با حجم زیاد که عمدتاً در قسمت شمالی رشته کوه بزقوش قرار گرفته­اند و با یک روند شرقی-غربی بر روی آندزیت­های مگاپورفیری ائوسن میانی قرار گرفته اند، دیده می­شوند و هم به صورت لنزهایی کوچک در بین سنگ­های ولکانی کلاستیکی جای گرفته­ان...

ارجمندزاده, رضا, الماسی, علیرضا, فرانسیسکو سانتوز, ژوزه, کریم‌پور, محمدحسن,

On the basis of field studies, mafic-intermediate bodies of Kashmar are subdivided into the old series (often stocks of gabbro, diorite, quartz diorite/monzodiorite) and the new series (quartz monzodiorite swarm dykes). In terms of crosscutting relationships, old series has the age between oldest volcanic units (57 Ma) and Eocene granitoids (40 Ma), but the swarm dykes are attributed to the pos...

Noghreyan, Mousa, Rezaei, Zahra, Saccani, Emilio,

Sabzevar ophiolitic pillow lavas contain variolitic, porphyritic with microlitic matrix, intersertal and amygdaloidal textures and include plagioclase, clinopyroxene (augite-diopside), olivine, amphibole (magnesiohastingsite) and opaque minerals. The chemical composition of clinopyroxenes show a calc-alkaline magmatic series and a tectonic environment within plate alkaline basalts. Geochemicall...

Journal: :journal of tethys 0

salafchegan-khorhe volcanic rocks are exposed within urumieh-dokhtar magmatic belt. different kinds of volcanic and subvolcanic rocks of calc-alkaline to alkaline character have been reported throughout this magmatic belt. since, isotopic investigations are very useful for detection of magma petrogenesis and because no isotopic studies have been done in this area, so a geochemical and isotopic ...

2013
arol D. Frost Ronald Frost

The Proterozoic eon is characterized by an unusual abundance of ferroan feldspathic rocks that range in composition from granite to quartz syenites to feldspathoid-bearing syenites. Three associations of ferroan rocks may be recognized on the basis of major element compositions: (1) metaluminous alkalic to alkali-calcic syenites and granites associated with anorthosites and iron-rich basaltic r...

2015
Jack L. Conrad Ulrich Joger

A new fossil showing affinities with extant Laemanctus offers the first clear evidence for a casquehead lizard (Corytophanidae) from the Eocene of North America. Along with Geiseltaliellus from roughly coeval rocks in central Europe, the new find further documents the tropical fauna present during greenhouse conditions in the northern mid-latitudes approximately 50 million years ago (Ma). Moder...

2010
LAWRENCE POWELL

The carbonatite problem can be stated as follows: Are carbonatites genetically related to sedimentary carbonate rocks, or are they derived from a silicate parent material? The isotopic composition of strontium in 21 carbonatites and in several related alkaline rocks has been determined. The mean Sr87/$r86 ratio for the 21 carbonatites is 0.7065 + 0.0003. The Sr87/sr86 ratios of sedimentary carb...

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