Results 81 to 90 of about 32,483 (245)

Some examples of deep structure of the Archean from geophysics [PDF]

open access: yes
The development of Archean crust remains as one of the significant problems in earth science, and a major unknown concerning Archean terrains is the nature of the deep crust.
Johnson, R. A.   +2 more
core   +1 more source

Characterizing the purple Earth: Modelling the globally-integrated spectral variability of the Archean Earth

open access: yes, 2013
The ongoing searches for exoplanetary systems have revealed a wealth of planets with diverse physical properties. Planets even smaller than the Earth have already been detected, and the efforts of future missions are placed on the discovery, and perhaps ...
Gutiérrez-Navarro, A. M.   +6 more
core   +1 more source

Earth science field work: Role and status [PDF]

open access: yes, 1988
This essay contends that the outstanding contributions currently being made to the earth sciences by theoretical and laboratory endeavors increase rather than decrease the need for sound field observations.
Sharp, Robert P.
core   +1 more source

Climate conditions on the South‐Iberian Palaeomargin during the latest Pliensbachian to early Toarcian: A mineralogical and geochemical study from hemipelagic deposits

open access: yesSedimentology, EarlyView.
ABSTRACT The integrated analysis of lithofacies, mineralogy and geochemistry of the hemipelagic marine succession exposed in La Cerradura section (South‐Iberian Palaeomargin) provides new information to characterise the palaeoenvironmental conditions during the latest Pliensbachian to early Toarcian, including the Jenkyns Event.
Chaima Ayadi   +4 more
wiley   +1 more source

A tale of two microbialites: Stromatolites and microbially induced sedimentary structures

open access: yesSedimentology, EarlyView.
ABSTRACT Microbialites are biosedimentary structures built by microbial mats. Five microbialite groups are distinguished: stromatolites, thrombolites, dendrolites, leiloites and microbially induced sedimentary structures (MISS). This contribution discusses the two most abundant microbialite groups in marine settings, stromatolites and MISS.
Nora Noffke, Stanley M. Awramik
wiley   +1 more source

Sedimentology of silica granules and haematite in the 3.47 Ga Antarctic Creek Member, Mount Ada Basalt, Western Australia

open access: yesSedimentology, EarlyView.
ABSTRACT The Paleoarchean Antarctic Creek Member of the Mount Ada Basalt, Eastern Pilbara Terrane, Western Australia, includes beds of jasper and white chert composed of sand‐sized silica granules that often contain or are mixed with silt‐sized particles of haematite.
Donald R. Lowe, Gary R. Byerly
wiley   +1 more source

Modern microbial landscape: Aerial mapping of microbially induced sedimentary structures forming in a coastal sabkha

open access: yesSedimentology, EarlyView.
ABSTRACT Microbially induced sedimentary structures (MISS) are considered important for understanding primitive life on Earth and for guiding the search for life on other planets. These structures are regarded as macroscopic fossils of early communities of unicellular organisms that did not produce skeletons or shells. In this study, field observations
Tomaso R. R. Bontognali   +8 more
wiley   +1 more source

Regional study of the Archean to Proterozoic crust at the Sudbury Neutrino Observatory (SNO+), Ontario: Predicting the geoneutrino flux

open access: yes, 2014
The SNO+ detector, a new kiloton scale liquid scintillator detector capable of recording geoneutrino events, will define the strength of the Earth radiogenic heat.
Huang, Yu   +5 more
core   +1 more source

Evolution Model for the Paleoproterozoic Talvivaara Mudstone‐Hosted Ni‐Zn‐Cu‐Co Deposit in Fennoscandia

open access: yesTerra Nova, EarlyView.
ABSTRACT The Paleoproterozoic Talvivaara mudstone is a very large sulfidic Ni‐Co deposit that records enhanced organic matter accumulation during the global Shunga Event. Here, rock geochemistry and microscale S and Fe isotope composition of in situ pyrrhotites and pyrites are studied in well‐characterised, well‐preserved drill core samples.
Raimo Lahtinen   +3 more
wiley   +1 more source

Ductile Extrusion Triggered by Continental Collision in NE Brazil

open access: yesTerra Nova, EarlyView.
ABSTRACT The Borborema Province in northeastern Brazil hosts one of the world's largest strike‐slip shear zone networks, active during the late Neoproterozoic assembly of West Gondwana. Whether these shear zones initiated during active continental collision or as a post‐orogenic response to far‐field stresses remains debated.
L. R. Tesser   +6 more
wiley   +1 more source

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