Numerous fresh ash layers comprise about 0.3 % by volume of Neogene to Holocene sediments drilled at Leg 104 Sites 642 and 643 (Wring Plateau, North Atlantic). Median grain sizes of the ashes are about 100 /xm and maximum grain sizes range up to 1200 fim. Rhyolitic pumice shards dominate, with minor...
Main Authors: | , , |
---|---|
Other Authors: | |
Format: | Text |
Language: | English |
Subjects: | |
Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.555.7430 http://www-odp.tamu.edu/publications/104_SR/VOLUME/CHAPTERS/sr104_18.pdf |
id |
ftciteseerx:oai:CiteSeerX.psu:10.1.1.555.7430 |
---|---|
record_format |
openpolar |
spelling |
ftciteseerx:oai:CiteSeerX.psu:10.1.1.555.7430 2023-05-15T16:51:23+02:00 P. R. Bitschene H. -u. Schmincke L. Viereck The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.555.7430 http://www-odp.tamu.edu/publications/104_SR/VOLUME/CHAPTERS/sr104_18.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.555.7430 http://www-odp.tamu.edu/publications/104_SR/VOLUME/CHAPTERS/sr104_18.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www-odp.tamu.edu/publications/104_SR/VOLUME/CHAPTERS/sr104_18.pdf text ftciteseerx 2016-01-08T11:46:11Z Numerous fresh ash layers comprise about 0.3 % by volume of Neogene to Holocene sediments drilled at Leg 104 Sites 642 and 643 (Wring Plateau, North Atlantic). Median grain sizes of the ashes are about 100 /xm and maximum grain sizes range up to 1200 fim. Rhyolitic pumice shards dominate, with minor bubble wall shards. Basaltic shards are poorly vesicular and blocky or round. Phenocrystic plagioclase, zircon, and clinopyroxene occur in the rhyolitic, pla-gioclase, and clinopyroxene phenocrysts and basaltic lithics in the basaltic tephra. Quartz, amphibole, clinozoisite, and rutile are interpreted as xenocrysts. All ash layers are well-sorted and represent distal fallout from major explosive erup-tions. Most ashes are rhyolitic (high-K and low-K) in composition, some are bimodal (tholeiitic and rhyolitic). Early Mio-cene tephra is dominantly basaltic. Iceland is inferred to be the likely source region for most ashes. Late Miocene high-K rhyolites may have originated from the K-rich Jan Mayen magmatic province. One Quaternary layer with biotite and alkali feldspar phenocrysts may have been derived from Jan Mayen Island. Four individual Pliocene to Holocene ash layers from Sites 642 and 643 can be correlated fairly well. Upper Miocene layers are tentatively correlated as a sequence between Sites 642 and 643. Average calculated layer frequencies are about three layers/m.y. through the Pliocene and Pleistocene and five to eight layers per m.y. through the middle and late Miocene, suggesting rather continuous volcanic activity in the North Atlantic. Episodic magmatic activity during Neogene epochs in this part of the North Atlantic, as postulated in the lit-erature, cannot be confirmed. Text Iceland Jan Mayen Jan Mayen Island North Atlantic Unknown Jan Mayen |
institution |
Open Polar |
collection |
Unknown |
op_collection_id |
ftciteseerx |
language |
English |
description |
Numerous fresh ash layers comprise about 0.3 % by volume of Neogene to Holocene sediments drilled at Leg 104 Sites 642 and 643 (Wring Plateau, North Atlantic). Median grain sizes of the ashes are about 100 /xm and maximum grain sizes range up to 1200 fim. Rhyolitic pumice shards dominate, with minor bubble wall shards. Basaltic shards are poorly vesicular and blocky or round. Phenocrystic plagioclase, zircon, and clinopyroxene occur in the rhyolitic, pla-gioclase, and clinopyroxene phenocrysts and basaltic lithics in the basaltic tephra. Quartz, amphibole, clinozoisite, and rutile are interpreted as xenocrysts. All ash layers are well-sorted and represent distal fallout from major explosive erup-tions. Most ashes are rhyolitic (high-K and low-K) in composition, some are bimodal (tholeiitic and rhyolitic). Early Mio-cene tephra is dominantly basaltic. Iceland is inferred to be the likely source region for most ashes. Late Miocene high-K rhyolites may have originated from the K-rich Jan Mayen magmatic province. One Quaternary layer with biotite and alkali feldspar phenocrysts may have been derived from Jan Mayen Island. Four individual Pliocene to Holocene ash layers from Sites 642 and 643 can be correlated fairly well. Upper Miocene layers are tentatively correlated as a sequence between Sites 642 and 643. Average calculated layer frequencies are about three layers/m.y. through the Pliocene and Pleistocene and five to eight layers per m.y. through the middle and late Miocene, suggesting rather continuous volcanic activity in the North Atlantic. Episodic magmatic activity during Neogene epochs in this part of the North Atlantic, as postulated in the lit-erature, cannot be confirmed. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
P. R. Bitschene H. -u. Schmincke L. Viereck |
spellingShingle |
P. R. Bitschene H. -u. Schmincke L. Viereck |
author_facet |
P. R. Bitschene H. -u. Schmincke L. Viereck |
author_sort |
P. R. Bitschene |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.555.7430 http://www-odp.tamu.edu/publications/104_SR/VOLUME/CHAPTERS/sr104_18.pdf |
geographic |
Jan Mayen |
geographic_facet |
Jan Mayen |
genre |
Iceland Jan Mayen Jan Mayen Island North Atlantic |
genre_facet |
Iceland Jan Mayen Jan Mayen Island North Atlantic |
op_source |
http://www-odp.tamu.edu/publications/104_SR/VOLUME/CHAPTERS/sr104_18.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.555.7430 http://www-odp.tamu.edu/publications/104_SR/VOLUME/CHAPTERS/sr104_18.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766041503713460224 |