نتایج جستجو برای: igneous petrology

تعداد نتایج: 4399  

Journal: :Geological Magazine 1916

Journal: :Science 2002
Christopher M Fedo Martin J Whitehouse

A quartz-pyroxene rock interpreted as a banded iron formation (BIF) from the island of Akilia, southwest Greenland, contains (13)C-depleted graphite that has been claimed as evidence for the oldest (>3850 million years ago) life on Earth. Field relationships on Akilia document multiple intense deformation events that have resulted in parallel transposition of Early Archean rocks and significant...

Journal: :Plant biology 2004
M E Puente C Y Li Y Bashan

Four bacterial species isolated from the rhizoplane of cacti growing in bare lava rocks were assessed for growth promotion of giant cardon cactus seedlings (Pachycereus pringlei). These bacteria fixed N(2), dissolved P, weathered extrusive igneous rock, marble, and limestone, and significantly mobilized useful minerals, such as P, K, Mg, Mn, Fe, Cu, and Zn in rock minerals. Cardon cactus seeds ...

2010
Aleksey V. Smirnov John A. Tarduno

In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: a b s t r a c t a r t i c l e i n f o Keywords: Siberian trap basalts mantle plume large igneous provinces One of the striki...

2004
Jun Korenaga

The frequent formation of large igneous provinces during the opening of the Atlantic Ocean is a surface manifestation of the thermal and chemical state of convecting mantle beneath the supercontinent Pangea. Recent geochemical and geophysical findings from the North Atlantic igneous province all point to the significant role of incomplete mantle mixing in igneous petrogenesis. On the basis of a...

2003
J. E. Hammer S Brachfeld M. J. Rutherford

Introduction: The presence of alternately magnetized sources on Mars indicates that at one time Mars had a magnetic field, presumably generated by an internal dynamo, and that its polarity reversed at least once before shutting off. Mars does not currently possess a magnetic field, so the anomalies are attributed to remanent magnetization (RM) of minerals in the crust. The initiation and cessat...

2013
Huapei Wang Dennis V. Kent

[1] We developed a paleointensity technique to account for concave-up Arai diagrams due to multidomain (MD) contributions to determine unbiased paleointensities for 24 trial samples from site GA-X in Pleistocene lavas from Floreana Island, Galapagos Archipelago. The main magnetization carrier is fine-grained low-titanium magnetite of variable grain size. We used a comprehensive back-zero-forth ...

Journal: :زمین شناسی اقتصادی 0
معصومه گودرزی سید سعید محمدی محمد حسین زرین کوب

introduction the area reviewed and studied in this paper is located 5 km southeast of sarbisheh city at eastern border of the lut block (jung et al., 1983; karimpour et al., 2011; richards et al., 2012) in eastern iran between 59° 47′ and 59° 53′ e longitude and 32°30′ and 32°34′ n latitude. the magmatic activity in the lut block began in middle jurassic (165-162 ma) and reached its peak in ter...

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