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| Main Authors: | , , |
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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
1999
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| Online Access: | https://doi.org/10.1594/PANGAEA.712082 |
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| _version_ | 1867168552854749184 |
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| author | Zhou, Weiming Van der Voo, Rob Peacor, Donald R |
| author_facet | Zhou, Weiming Van der Voo, Rob Peacor, Donald R |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Transmission electron microscopy observations and rock magnetic measurements reveal that alteration of fine- and large-grained iron-titanium oxides can occur at different rates. Fine-grained titanomagnetite occurs as a crystallization product within interstitial glass that originated as an immiscible liquid within a fully differentiated melt; in several samples with ages to 32 Ma it displays very little or no oxidation (z = ca. 0). In contrast, samples with ages of 10 Ma or older are observed to also contain highly oxidized (z >/= 0.66) large-grained titanomaghemite. These large grains, having originated by direct crystallization from melt, are associated with pore space. Such pore space can serve as a conduit for fluids that promote alteration, whereas fine grains may have been "armored" against alteration by the glass matrix in which they are embedded. Apparently, alteration of oceanic crust is a heterogeneous process on a microscopic scale. The existence of pristine, fine-grained titanomagnetite in the interstitial glass of older ocean-floor basalts that have undergone significant alteration implies that such glassy material is capable of carrying original thermal remanent magnetization and may be suitable for paleointensity determinations. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_712082 |
| institution | PANGAEA |
| language | en |
| publishDate | 1999 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Comparisons of z values between fine-grained titanomagnetites within interstitial glass and large-grained titanomaghemtes in older ocean-floor basalts Zhou, Weiming Van der Voo, Rob Peacor, Donald R 34-320B; 37-335; 73-519A; 82-556; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg34; Leg37; Leg73; Leg82; North Atlantic/RIDGE; North Atlantic Ocean; South Atlantic/RIDGE; South Pacific/BASIN Transmission electron microscopy observations and rock magnetic measurements reveal that alteration of fine- and large-grained iron-titanium oxides can occur at different rates. Fine-grained titanomagnetite occurs as a crystallization product within interstitial glass that originated as an immiscible liquid within a fully differentiated melt; in several samples with ages to 32 Ma it displays very little or no oxidation (z = ca. 0). In contrast, samples with ages of 10 Ma or older are observed to also contain highly oxidized (z >/= 0.66) large-grained titanomaghemite. These large grains, having originated by direct crystallization from melt, are associated with pore space. Such pore space can serve as a conduit for fluids that promote alteration, whereas fine grains may have been "armored" against alteration by the glass matrix in which they are embedded. Apparently, alteration of oceanic crust is a heterogeneous process on a microscopic scale. The existence of pristine, fine-grained titanomagnetite in the interstitial glass of older ocean-floor basalts that have undergone significant alteration implies that such glassy material is capable of carrying original thermal remanent magnetization and may be suitable for paleointensity determinations. |
| title | Comparisons of z values between fine-grained titanomagnetites within interstitial glass and large-grained titanomaghemtes in older ocean-floor basalts |
| topic | 34-320B; 37-335; 73-519A; 82-556; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg34; Leg37; Leg73; Leg82; North Atlantic/RIDGE; North Atlantic Ocean; South Atlantic/RIDGE; South Pacific/BASIN |
| url | https://doi.org/10.1594/PANGAEA.712082 |