Zobrazeno 1 - 10
of 119
pro vyhledávání: '"Stephen Moorbath"'
Autor:
Clark M. Johnson, Andrew D. Czaja, Eric E. Roden, Brian L. Beard, Stephen Moorbath, Weiqiang Li
Publikováno v:
Earth and Planetary Science Letters. 363:192-203
The redox balance of the Archean atmosphere–ocean system is among the most significant uncertainties in our understanding of the earliest history of Earth's surface zone. Most workers agree that oxygen did not constitute a significant proportion of
Publikováno v:
Nature. 477:195-198
It has long been speculated that a 'late heavy bombardment' of Earth by meteoritic material replenished the mantle's budget of siderophile (iron-loving) elements, such as tungsten, that were largely lost to the core during its segregation. However, e
Autor:
Stephen Moorbath
Publikováno v:
Applied Geochemistry. 24:1087-1092
Autor:
Stephen Moorbath
Publikováno v:
Notes and Records: the Royal Society Journal of the History of Science. 63:381-392
In the mid 1960s, a young New Zealand geologist named Vic McGregor (1940–2000) was commissioned by the Copenhagen-based Geological Survey of Greenland to make a geological map of a large region of complex ancient rocks in the southern part of West
Publikováno v:
Geochimica et Cosmochimica Acta. 70:164-191
We present new ultra-high precision 142 Nd/ 144 Nd measurements of early Archaean rocks using the new generation thermal ionization mass spectrometer Triton. Repeated measurements of the Ames Nd standard demonstrate that the 142 Nd/ 144 Nd ratio can
Publikováno v:
Earth and Planetary Science Letters. 240:276-290
The oldest known bona fide succession of elastic metasediments Occurs in the Isua Greenstone Belt. SW Greenland and consists of a variety of mica schists and rare metaconglomerates. The metasediments are in direct contact with a felsic metavolcanic l
Autor:
Stephen Moorbath
Publikováno v:
Applied Geochemistry. 20:819-824
Many geologists have their own favourite part of the vast geological time scale, from which there is plenty to choose for all types of pure and applied research, and for detailed speculation. My own favourite is that ancient time range during which t
Publikováno v:
Geochimica et Cosmochimica Acta. 69:1555-1573
New and published major and trace element abundances of elastic metasediments (mainly garnet-biotite-plagioclase schists) from the similar to 3.8 Ga Isua Greenstone Belt (IGB), southern West Greenland, are used in an attempt to identify the compositi
Publikováno v:
Earth and Planetary Science Letters. 222:43-60
Rare earth element (REE) plus yttrium (Y) patterns of modem seawater have characteristic features that can be used as chemical fingerprints. Reliable proxies for marine REE + Y chemistry have been demonstrated from a large geological time span, inclu
Publikováno v:
Precambrian Research. 126:309-312
Spherical objects, identified as microfossils and named Isuasphaera isua (Pflug), were reported in 1978 from a chert in the 3.7–3.8 Ga Isua Greenstone Belt (IGB). Soon afterwards the biological nature of these objects was questioned on a number of