Insights into the diagenetic environment of fossil marine vertebrates of the Pisco Formation (late Miocene, Peru) from mineralogical and Sr-isotope data

2018 ◽  
Vol 81 ◽  
pp. 141-152 ◽  
Author(s):  
A. Gioncada ◽  
R. Petrini ◽  
G. Bosio ◽  
K. Gariboldi ◽  
A. Collareta ◽  
...  
Keyword(s):  
Late Miocene ◽  
Sr Isotope ◽  
Isotope Data ◽  
Pisco Formation ◽  
Marine Vertebrates ◽  
Diagenetic Environment

Origin of the Ordovician Mansehra granite in the NW Himalaya, Pakistan: constraints from Sr–Nd isotopic data, zircon U–Pb age and Hf isotopes

2018 ◽  
Vol 481 (1) ◽  
pp. 277-298 ◽  
Author(s):  
Masatsugu Ogasawara ◽  
Mayuko Fukuyama ◽  
Rehanul Haq Siddiqui ◽  
Ye Zhao
Keyword(s):  
Granitic Magma ◽  
Geochemical Data ◽  
Large Contribution ◽  
Crustal Material ◽  
Sr Isotope ◽  
Nw Himalaya ◽  
Nd Isotope ◽  
Isotope Data ◽  
Late Neoproterozoic ◽  
T Values

AbstractThe Mansehra granite in the NW Himalaya is a typical Lesser Himalayan granite. We present here new whole-rock geochemistry, Rb–Sr and Sm–Nd isotope data, together with zircon U–Pb ages and Hf isotope data, for the Mansehra granite. Geochemical data for the granite show typical S-type characteristics. Zircon U–Pb dating yields 206Pb/238U crystallization ages of 483–476 Ma. The zircon grains contain abundant inherited cores and some of these show a clear detrital origin. The 206Pb/238U ages of the inherited cores in the granite cluster in the ranges 889–664, 1862–1595 and 2029 Ma. An age of 664 Ma is considered to be the maximum age of the sedimentary protoliths. Thus the Late Neoproterozoic to Cambrian sedimentary rocks must be the protolith of the Mansehra granitic magma. The initial Sr isotope ratios are high, ranging from 0.7324 to 0.7444, whereas the εNd(t) values range from −9.2 to −8.6, which strongly suggests a large contribution of old crustal material to the protoliths. The two-stage Nd model ages and zircon Hf model ages are Paleoproterozoic, indicating that the protolith sediments were derived from Paleoproterozoic crustal components.

scholarly journals Stratigraphic framework of the late Miocene Pisco Formation at Cerro Los Quesos (Ica Desert, Peru)

2015 ◽  
Vol 12 (5) ◽  
pp. 1020-1028 ◽  
Author(s):  
C. Di Celma ◽  
E. Malinverno ◽  
G. Cantalamessa ◽  
A. Gioncada ◽  
G. Bosio ◽  
...  
Keyword(s):  
Late Miocene ◽  
Pisco Formation ◽  
Stratigraphic Framework

scholarly journals Geochemical and Nd, Pb, and Sr Isotope Data from Deccan Alkaline Complexes--Inferences for Mantle Sources and Plume-Lithosphere Interaction

1998 ◽  
Vol 39 (11-12) ◽  
pp. 1847-1864 ◽  
Author(s):  
A. Simonetti ◽  
S. L. Goldstein ◽  
S. S. Schmidberger ◽  
S. G. Viladkar
Keyword(s):  
Sr Isotope ◽  
Isotope Data ◽  
Mantle Sources ◽  
Alkaline Complexes

The origin of basic rocks of the Korosten AMCG complex, Ukrainian shield: Implication of Nd and Sr isotope data

Lithos ◽  
2006 ◽  
Vol 90 (3-4) ◽  
pp. 214-222 ◽  
Author(s):  
Leonid Shumlyanskyy ◽  
Rob M. Ellam ◽  
Olexander Mitrokhin
Keyword(s):  
Ukrainian Shield ◽  
Sr Isotope ◽  
Isotope Data ◽  
Basic Rocks

Geochemical and Geophysical Evidence for Late Miocene Onset of Tasman Leakage

2020 ◽  
Author(s):  
Beth Christensen ◽  
David DeVleeschouwer ◽  
Jeroen Groeneveld ◽  
Jorijntje Henderiks ◽  
Gerald Auer ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Ocean Circulation ◽  
Late Miocene ◽  
Return Flow ◽  
Intermediate Water ◽  
Isotope Data ◽  
The North ◽  
Tasman Sea ◽  
Intermediate Waters

<p>The recent documentation of the southern hemisphere “supergyre”, the coupled subtropical southern hemisphere gyres spanning the 3 ocean basins, leads to questions about its impact on Indian Ocean circulation. The Indonesian Throughflow (ITF) acts as a switchboard directing warm surface waters towards the Agulhas Current (AC) and return flow to the North Atlantic, but Tasman Leakage (TL) is another source of return flow, however, at intermediate water depths. Fed by a complex mixture of South Pacific (SP) western boundary current surface and intermediate waters, and Antarctic Intermediate Water (AAIW), today the topography forces it to flow in a westerly direction. The TL flows over the Broken Ridge towards Madagascar, joining the AC and ultimately Atlantic Meridional Circulation (AMOC).</p><p>Stable isotope data from 4 DSPD/ ODP Indian Ocean sites define the history of TL and constrain the timing of its onset to ~7 Ma.  A simple nannofossil- biostratigraphy age model applied to previously published benthic foraminiferal carbon isotope data ensures the 4 time-series (~11 – 2 Ma) are consistent. All 4 records (Sites 752 Broken Ridge, 590 Tasman Sea, 757 90 East Ridge, 751 Kerguelen Plateau) are similar from ~11 Ma to ~7 Ma, indicating the Tasman Sea intermediate water was sourced from the Southern Ocean (SO). A coeval shift at ~7 Ma at Sites 590 and 752 signals a SP contribution and the onset of TL. We do not observe TL at Sites 757 and 751 and so interpret the post-7 Ma divergence between the TL pair and the KP / 90E Ridge sites as a reflection of different intermediate water masses. The KP / 90E Ridge sites record a more fully SO signal, and these waters are constrained to the region west of the 90 East ridge.</p><p>The isotopic record of TL onset suggests important tectonic changes ~ 7 Ma: 1) opening of the Tasman Sea to the north and 2) Australia’s northward motion allowing westward flow around Tasmania. The former is supported by a change in sedimentation style on the Marion Plateau (ODP Site 1197). The latter is supported by unconformities on the South Australian Bight margin (Leg 182 Sites 1126 (784 m), 1134 (701 m), 1130 (488m) and coeval decreases in mud- sized sediments at the Broken Ridge sites, indicating winnowing associated with the onset of the TL. A divergence is also apparent between Broken Ridge and Mascarene Plateau Site 707 records at this time. These events, coupled with the temporal relationship between the onset of the TL and a change in the character of deposition in the Maldives indicate enhanced Indian Ocean circulation at intermediate depths coincident with the late Miocene global cooling. Combined, these observations suggest the Indian Ocean in general plays a larger role in the global ocean system than previously recognized, and intermediate waters in particular are a critical yet poorly understood component of AMOC.</p>

scholarly journals Orbitally-Tuned Sr Isotope Chemostratigraphy for the Late Middle to Late Miocene

1999 ◽  
Vol 14 (1) ◽  
pp. 74-83 ◽  
Author(s):  
E. E. Martin ◽  
N. J. Shackleton ◽  
J. C. Zachos ◽  
B. P. Flower
Keyword(s):  
Late Miocene ◽  
Sr Isotope

Late Miocene palaeo-oceanography of the Atlantic: oxygen isotope data on planktonic and benthic Foraminifera

Nature ◽  
1980 ◽  
Vol 283 (5747) ◽  
pp. 555-557 ◽  
Author(s):  
R. K. Matthews ◽  
W. B. Curry ◽  
K. C. Lohmann ◽  
M. A. Sommer ◽  
R. Z. Poore
Keyword(s):  
Oxygen Isotope ◽  
Late Miocene ◽  
Benthic Foraminifera ◽  
Isotope Data ◽  
Oxygen Isotope Data
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