Evaluating the Ca isotope proxy

Online Access: Get full text
doi: 10.2475/03.2010.03
Author(s): Fantle, Matthew S.
Author Affiliation(s): Primary:
Pennsylvania State University, Geosciences Department, University Park, PA, United States
Volume Title: American Journal of Science
Source: American Journal of Science, 310(3), p.194-230. Publisher: Yale University, Kline Geology Laboratory, New Haven, CT, United States. ISSN: 0002-9599 CODEN: AJSCAP
Note: In English. 120 refs.; illus., incl. sketch map
Summary: The use of Ca isotopes as a proxy for mass flux imbalances in the Ca cycle is evaluated critically. A compiled Ca isotope record for the last 45 Ma, derived from bulk nannofossil ooze and with a temporal resolution of ∼0.5 Ma, and an interpretation of the record are presented in the context of the global Ca cycle. This analysis, which assumes that nannofossil ooze records isotopic variations in seawater, indicates a dynamic Ca cycle in the Cenozoic. Such dynamic behavior has serious implications for the C cycle and suggests feedbacks between the Ca and C cycles to stabilize, or buffer, the oceanic carbon reservoir. Alternative applications of the Ca isotope proxy are investigated, using numerical models to determine the extent to which Ca isotopes are sensitive to other aspects of the Ca cycle; the results of the simulations are applied to specific cases in the Cenozoic. The simulations illustrate how variations in the global fractionation factor between calcium carbonate and seawater can produce trends similar to those observed when comparing previously published Ca isotopic compositions of marine barite to the nannofossil ooze record. The large drop in the δ44Ca value of bulk nannofossil ooze near the Eocene-Oligocene boundary can be reconciled in two ways, either as a substantial increase in weathering relative to sedimentation or as an indicator of changing depositional mode within the ocean. Though the preferred interpretation is not clear at present, it is evident that Ca isotopes stand to be a unique proxy for Ca cycling once the isotope systematics are elucidated.
Year of Publication: 2010
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Alkaline earth metals; Angola Basin; Atlantic Ocean; Bioclastic sedimentation; Ca-44; Calcium; Carbonate sediments; Cenozoic; Clastic sediments; Coccolithophoraceae; DSDP Site 167; DSDP Site 214; DSDP Site 400; DSDP Site 522; DSDP Site 590; Data bases; Data processing; Deep Sea Drilling Project; Digital simulation; East Pacific; Eocene; Equatorial Pacific; Geochemical cycle; Geochemistry; Global; IPOD; Indian Ocean; Integrated Ocean Drilling Program; Isotopes; Leg 130; Leg 17; Leg 22; Leg 48; Leg 73; Leg 90; Lord Howe Rise; Marine sediments; Metals; Microfossils; Monte Carlo analysis; Nannofossils; Ninetyeast Ridge; North Atlantic; North Pacific; Northeast Pacific; Northwest Pacific; Numerical models; ODP Site 807; Ocean Drilling Program; Oligocene; Ontong Java Plateau; Ooze; Pacific Ocean; Paleo-oceanography; Paleogene; Plantae; Quaternary; STELLA; Sedimentation; Sediments; South Atlantic; South Pacific; Southwest Pacific; Stable isotopes; Statistical analysis; Tertiary; West Pacific
Coordinates: N001906 N033626 E1613538 E1563728
S200000 N090000 E1030000 E0860000
N470000 N570000 W0080000 W0240000
S293000 S253000 E0034000 W0114000
S453129 S211153 E1745653 E1611336
Record ID: 2010059202
Copyright Information: GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data from the American Journal of Science, Yale University, Kline Geology Laboratory, New Haven, CT, United States
LEADER 06259naaaa2201177zu 4500
001 2010059202
003 ViAlAGI
005 20180131213115.0
008 160927e201003 ctua 0 0 eng d
034 0 |a a  |d E1563728  |e E1613538  |f N033626  |g N001906 
034 0 |a a  |d E0860000  |e E1030000  |f N090000  |g S200000 
034 0 |a a  |d W0240000  |e W0080000  |f N570000  |g N470000 
034 0 |a a  |d W0114000  |e E0034000  |f S253000  |g S293000 
034 0 |a a  |d E1611336  |e E1745653  |f S211153  |g S453129 
040 |a ViAlAGI  |c ViAlAGI 
072 7 |a 12  |2 georeft 
072 7 |a 02D  |2 georeft 
100 1 |a Fantle, Matthew S.  |u Pennsylvania State University, Geosciences Department, University Park, PA 
245 1 0 |a Evaluating the Ca isotope proxy 
300 |a p. 194-230 
500 |a In English. 120 refs. 
500 |a Research program: DSDP Deep Sea Drilling Project 
500 |a Research program: IODP Integrated Ocean Drilling Program 
500 |a Research program: IPOD International Phase of Ocean Drilling 
500 |a Research program: ODP Ocean Drilling Program 
500 |a Affiliation: Pennsylvania State University, Geosciences Department; University Park, PA; USA; United States 
500 |a Source note: American Journal of Science, 310(3), p.194-230. Publisher: Yale University, Kline Geology Laboratory, New Haven, CT, United States. ISSN: 0002-9599 
500 |a Publication type: journal article 
504 |b 120 refs. 
510 3 |a GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data from the American Journal of Science, Yale University, Kline Geology Laboratory, New Haven, CT, United States 
520 |a The use of Ca isotopes as a proxy for mass flux imbalances in the Ca cycle is evaluated critically. A compiled Ca isotope record for the last 45 Ma, derived from bulk nannofossil ooze and with a temporal resolution of ∼0.5 Ma, and an interpretation of the record are presented in the context of the global Ca cycle. This analysis, which assumes that nannofossil ooze records isotopic variations in seawater, indicates a dynamic Ca cycle in the Cenozoic. Such dynamic behavior has serious implications for the C cycle and suggests feedbacks between the Ca and C cycles to stabilize, or buffer, the oceanic carbon reservoir. Alternative applications of the Ca isotope proxy are investigated, using numerical models to determine the extent to which Ca isotopes are sensitive to other aspects of the Ca cycle; the results of the simulations are applied to specific cases in the Cenozoic. The simulations illustrate how variations in the global fractionation factor between calcium carbonate and seawater can produce trends similar to those observed when comparing previously published Ca isotopic compositions of marine barite to the nannofossil ooze record. The large drop in the δ>44`Ca value of bulk nannofossil ooze near the Eocene-Oligocene boundary can be reconciled in two ways, either as a substantial increase in weathering relative to sedimentation or as an indicator of changing depositional mode within the ocean. Though the preferred interpretation is not clear at present, it is evident that Ca isotopes stand to be a unique proxy for Ca cycling once the isotope systematics are elucidated. 
650 7 |a Algae  |2 georeft 
650 7 |a Alkaline earth metals  |2 georeft 
650 7 |a Bioclastic sedimentation  |2 georeft 
650 7 |a Ca-44  |2 georeft 
650 7 |a Calcium  |2 georeft 
650 7 |a Carbonate sediments  |2 georeft 
650 7 |a Cenozoic  |2 georeft 
650 7 |a Clastic sediments  |2 georeft 
650 7 |a Coccolithophoraceae  |2 georeft 
650 7 |a Data bases  |2 georeft 
650 7 |a Data processing  |2 georeft 
650 7 |a Deep Sea Drilling Project  |2 georeft 
650 7 |a Digital simulation  |2 georeft 
650 7 |a Eocene  |2 georeft 
650 7 |a Geochemical cycle  |2 georeft 
650 7 |a Geochemistry  |2 georeft 
650 7 |a Global  |2 georeft 
650 7 |a Integrated Ocean Drilling Program  |2 georeft 
650 7 |a Isotopes  |2 georeft 
650 7 |a Marine sediments  |2 georeft 
650 7 |a Metals  |2 georeft 
650 7 |a Microfossils  |2 georeft 
650 7 |a Monte Carlo analysis  |2 georeft 
650 7 |a Nannofossils  |2 georeft 
650 7 |a Numerical models  |2 georeft 
650 7 |a Ocean Drilling Program  |2 georeft 
650 7 |a Oligocene  |2 georeft 
650 7 |a Ooze  |2 georeft 
650 7 |a Paleo-oceanography  |2 georeft 
650 7 |a Paleogene  |2 georeft 
650 7 |a Plantae  |2 georeft 
650 7 |a Quaternary  |2 georeft 
650 7 |a Sedimentation  |2 georeft 
650 7 |a Sediments  |2 georeft 
650 7 |a Statistical analysis  |2 georeft 
650 7 |a Tertiary  |2 georeft 
650 7 |a Stable isotopes  |2 georeft 
651 7 |a Angola Basin  |2 georeft 
651 7 |a Atlantic Ocean  |2 georeft 
651 7 |a DSDP Site 167  |2 georeft 
651 7 |a DSDP Site 214  |2 georeft 
651 7 |a DSDP Site 400  |2 georeft 
651 7 |a DSDP Site 522  |2 georeft 
651 7 |a DSDP Site 590  |2 georeft 
651 7 |a East Pacific  |2 georeft 
651 7 |a Equatorial Pacific  |2 georeft 
651 7 |a Indian Ocean  |2 georeft 
651 7 |a IPOD  |2 georeft 
651 7 |a Leg 130  |2 georeft 
651 7 |a Leg 17  |2 georeft 
651 7 |a Leg 22  |2 georeft 
651 7 |a Leg 48  |2 georeft 
651 7 |a Leg 73  |2 georeft 
651 7 |a Leg 90  |2 georeft 
651 7 |a Lord Howe Rise  |2 georeft 
651 7 |a Ninetyeast Ridge  |2 georeft 
651 7 |a North Atlantic  |2 georeft 
651 7 |a North Pacific  |2 georeft 
651 7 |a Northeast Pacific  |2 georeft 
651 7 |a Northwest Pacific  |2 georeft 
651 7 |a ODP Site 807  |2 georeft 
651 7 |a Ontong Java Plateau  |2 georeft 
651 7 |a Pacific Ocean  |2 georeft 
651 7 |a South Atlantic  |2 georeft 
651 7 |a South Pacific  |2 georeft 
651 7 |a Southwest Pacific  |2 georeft 
651 7 |a West Pacific  |2 georeft 
653 |a STELLA 
773 0 |t American Journal of Science  |d New Haven, CT : Yale University, Kline Geology Laboratory, Mar. 2010  |x 0002-9599  |y AJSCAP  |n American Journal of Science, 310(3), p.194-230. Publisher: Yale University, Kline Geology Laboratory, New Haven, CT, United States. ISSN: 0002-9599 Publication type: journal article  |g Vol. 310, no. 3  |h illus., incl. sketch map 
856 |u urn:doi: 10.2475/03.2010.03