| 1. |
|
|
| 2. |
- Evans, David A.D., et al.
(författare)
-
An expanding list of reliable paleomagnetic poles for Precambrian tectonic reconstructions
- 2021
-
Ingår i: Ancient Supercontinents and the Paleogeography of Earth. - : Elsevier. ; , s. 605-639
-
Bokkapitel (refereegranskat)abstract
- We present a compilation of reliable Precambrian paleomagnetic poles from three successive international workshops (in years 2009, 2014, 2017), comprising paleomagnetists specializing in Precambrian tectonic reconstructions. The working groups compiled lists of two global classes of poles, published through the end of 2017. “Grade-A” results are judged to provide essential constraints on tectonic reconstructions; “Grade-B” poles are judged to be suggestive of high-quality, but not yet demonstrated to be primary, or perhaps lacking precise geochronologic or other constraints. Our catalog documents a resurgence of high-quality data acquisition in recent years, and highlights specific cratons and time intervals that are most lacking in the data needed to reconstruct those blocks through supercontinental cycles.
|
|
| 3. |
- Evans, D. A D, et al.
(författare)
-
Return to Rodinia? Moderate to high palaeolatitude of the São Francisco/Congo craton at 920 Ma
- 2015. - 1
-
Ingår i: Geological Society Special Publication. - 0305-8719. ; 424:1, s. 167-190
-
Bokkapitel (refereegranskat)abstract
- Moderate to high palaeolatitudes recorded in mafic dykes, exposed along the coast of Bahia, Brazil, are partly responsible for some interpretations that the São Francisco/Congo craton was separate from the low-latitude Rodinia supercontinent at about 1050 Ma. We report new palaeomagnetic data that replicate the previous results. However, we obtain substantially younger U-Pb baddeleyite ages from five dykes previously thought to be 1.02-1.01 Ga according to the 40Ar/39Ar method. Specifically, the so-called «A-normal» remanence direction from Salvador is dated at 924.2±3.8 Ma, within error of the age for the «C» remanence direction at 921.5±4.3 Ma. An «A-normal» dyke at Ilh»us is dated at 926.1±4.6 Ma, and two «A-normal» dykes at Olivença have indistinguishable ages with best estimate of emplacement at 918.2±6.7 Ma. We attribute the palaeomagnetic variance of the «A-normal» and «C» directions to lack of averaging of geomagnetic palaeosecular variation in some regions. Our results render previous 40Ar/39Ar ages from the dykes suspect, leaving late Mesoproterozoic palaeolatitudes of the São Francisco/Congo craton unconstrained. The combined «A-normal» palaeomagnetic pole from coastal Bahia places the São Francisco/Congo craton in moderate to high palaeolatitudes at c. 920 Ma, allowing various possible positions of that block within Rodinia.
|
|
| 4. |
- Hawkins, Stephen J., et al.
(författare)
-
The Intertidal Zone of the North-East Atlantic Region
- 2019
-
Ingår i: Interactions in the Marine Benthos: Global Patterns and Processes (Systematics Association Special Volume Series, pp. 7-46). - : Cambridge university press. - 9781108416085
-
Bokkapitel (refereegranskat)abstract
- The rocky shores of the north-east Atlantic have been long studied. Our focus is from Gibraltar to Norway plus the Azores and Iceland. Phylogeographic processes shape biogeographic patterns of biodiversity. Long-term and broadscale studies have shown the responses of biota to past climate fluctuations and more recent anthropogenic climate change. Inter- and intra-specific species interactions along sharp local environmental gradients shape distributions and community structure and hence ecosystem functioning. Shifts in domination by fucoids in shelter to barnacles/mussels in exposure are mediated by grazing by patellid limpets. Further south fucoids become increasingly rare, with species disappearing or restricted to estuarine refuges, caused by greater desiccation and grazing pressure. Mesoscale processes influence bottom-up nutrient forcing and larval supply, hence affecting species abundance and distribution, and can be proximate factors setting range edges (e.g., the English Channel, the Iberian Peninsula). Impacts of invasive non-native species are reviewed. Knowledge gaps such as the work on rockpools and host–parasite dynamics are also outlined.
|
|
| 5. |
- Fortelius, Mikael, et al.
(författare)
-
The Origin and Early History of NOW as It Happened
- 2023
-
Ingår i: Evolution of Cenozoic Land Mammal Faunas and Ecosystems: 25 years of the NOW database of fossil mammals.. - : Springer. ; , s. 7-32
-
Bokkapitel (refereegranskat)abstract
- The NOW database of fossil mammals came to be through a confluence of several initiatives spanning multiple decades. The first public version of NOW database was released in 1996 and the first Advisory Board was established the year after. Originally, NOW stood for Neogene of the Old World but with the gradual expansion of the database the acronym was eventually reassigned to stand for New and Old Worlds. The structure of what would become NOW was originally cloned from the ETE database of the Smithsonian Institution and the first NOW version accessible over the internet was a node of the ETE database. The first standalone, online version of NOW was launched in 2005 and the first formal steering group was established in 2009. During its existence, NOW has been funded, directly or indirectly, by several organizations but fundamentally it has always been an unfunded community effort, dependent on voluntary work by the participants.
|
|
| 6. |
|
|
| 7. |
- Pesonen, Lauri J., et al.
(författare)
-
Precambrian supercontinents and supercycles—an overview
- 2021
-
Ingår i: Ancient Supercontinents and the Paleogeography of Earth. - : Elsevier. ; , s. 1-50
-
Bokkapitel (refereegranskat)abstract
- There is ample evidence that supercontinent cycles on Earth have been operating since the Late Paleoproterozoic. Evidence for the supercontinent cyclicity arises from multidisciplinary observations from geology, geochronology, geophysics (e.g., paleomagnetism, seismology, heat flow), isotope geology, and geochemistry. This overview summarizes current views of Precambrian supercontinent episodicity or cyclicity. In addition, paleogeographic reconstructions based on global key paleomagnetic poles and kinematic models of Paleo-Mesoproterozoic Nuna supercycle, Meso-Neoproterozoic Rodinia supercycle, and the Phanerozoic Gondwana/Pangea supercycle are explored. The lifecycle of supercontinents is tested by geological, geophysical, and geochemical data coupled with secular evolution trends of Earth. Results suggest that (1) supercontinent cyclicity has a characteristic (quasi-) period of ~700–500 million years, supported by planetary secular evolutionary trends, but other periods are also present; (2) supercontinents Nuna, Rodinia, and Gondwana/Pangea have different configurations and secular evolutionary trends possibly due to different tectonic styles of assembly; (3) globally averaged plate velocity during the Precambrian reveals a wave-like pattern with peaks and lows corresponding with features in several secular evolution indices including the distribution of U−Pb ages, passive margins, metamorphic events, tectonic proxies, and magmatic activity; (4) the data suggest three tectonomagmatic lulls during the Proterozoic, but the proposed Mesoproterozoic quiescent period, coined as “boring billion” years of Earth history (1.8–0.8 Ga) appears to be seen mainly by atmospheric and biospheric data rather than tectonomagmatic activity; and (5) tectonic processes driving supercontinent cyclicity are interactive, with feedbacks from all six spheres of the Earth—the geosphere, cryosphere, hydrosphere, biosphere, atmosphere, and magnetosphere.
|
|
| 8. |
- Pesonen, Lauri J., et al.
(författare)
-
Preface
- 2021
-
Ingår i: Ancient Supercontinents and the Paleogeography of Earth. - : Elsevier. ; , s. xv-xvi
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 9. |
|
|
