10.1594/PANGAEA.693664
Muttoni, Giovanni
Giovanni
Muttoni
0000-0001-7908-1664
Kent, Dennis V
Dennis V
Kent
0000-0002-7677-2993
Chert intervals in DSDP and ODP sites (Table 1)
PANGAEA
2007
Event label
Latitude of event
Longitude of event
Elevation of event
AGE
Age, minimum/young
Age, maximum/old
Area/locality
Biozone
Comment
Duration
Paleolatitude
Paleolongitude
Composite Core
Drilling/drill rig
Leg3
Leg5
Leg8
Leg10
Leg11
Leg12
Leg15
Leg16
Leg17
Leg18
Leg21
Leg22
Leg23
Leg28
Leg31
Leg32
Leg33
Leg39
Leg41
Leg43
Leg44
Leg47
Leg48
Leg50
Leg57
Leg61
Leg62
Leg63
Leg72
Leg75
Leg79
Leg81
Leg89
Leg95
Leg101
Leg112
Leg113
Leg114
Leg115
Leg119
Leg120
Leg121
Leg122
Leg123
Leg159
Leg165
Leg171B
Leg177
Leg182
Leg183
Leg192
Leg199
Leg206
Leg208
Leg150X
Glomar Challenger
Joides Resolution
Deep Sea Drilling Project (DSDP)
Ocean Drilling Program (ODP)
1968-12-03T00:00:00/2003-04-15T00:00:00
en
Supplementary Dataset
10.1016/j.palaeo.2007.06.008
1296 data points
text/tab-separated-values
Creative Commons Attribution 3.0 Unported
Radiolarian cherts in the Tethyan realm of Jurassic age were recently interpreted as resulting from high biosiliceous productivity along upwelling zones in subequatorial paleolatitudes the locations of which were confirmed by revised paleomagnetic estimates. However, the widespread occurrence of cherts in the Eocene suggests that cherts may not always be reliable proxies of latitude and upwelling zones. In a new survey of the global spatio-temporal distribution of Cenozoic cherts in Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) sediment cores, we found that cherts occur most frequently in the Paleocene and early Eocene, with a peak in occurrences at ~50 Ma that is coincident with the time of highest bottom water temperatures of the early Eocene climatic optimum (EECO) when the global ocean was presumably characterized by reduced upwelling efficiency and biosiliceous productivity. Cherts occur less commonly during the subsequent Eocene global cooling trend. Primary paleoclimatic factors rather than secondary diagenetic processes seem therefore to control chert formation. This timing of peak Eocene chert occurrence, which is supported by detailed stratigraphic correlations, contradicts currently accepted models that involve an initial loading of large amounts of dissolved silica from enhanced weathering and/or volcanism in a supposedly sluggish ocean of the EECO, followed during the subsequent middle Eocene global cooling by more vigorous oceanic circulation and consequent upwelling that made this silica reservoir available for enhanced biosilicification, with the formation of chert as a result of biosilica transformation during diagenesis. Instead, we suggest that basin-basin fractionation by deep-sea circulation could have raised the concentration of EECO dissolved silica especially in the North Atlantic, where an alternative mode of silica burial involving widespread direct precipitation and/or absorption of silica by clay minerals could have been operative in order to maintain balance between silica input and output during the upwelling-deficient conditions of the EECO. Cherts may therefore not always be proxies of biosiliceous productivity associated with latitudinally focused upwelling zones.
Supplement to: Muttoni, Giovanni; Kent, Dennis V (2007): Widespread formation of cherts during the early Eocene climate optimum. Palaeogeography, Palaeoclimatology, Palaeoecology, 253(3-4), 348-362
2.63923333333333
-2.733283333333304
-64.517
57.496
North Atlantic/CONT RISE
North Pacific/HILL
North Pacific/BASIN
North Pacific/PLAIN
South Pacific
Gulf of Mexico/KNOLL
North Atlantic/CHANNEL
North Atlantic/KNOLL
North Atlantic/BASIN
North Atlantic/BANK
North Atlantic/SEAMOUNT
Caribbean Sea/BASIN
Caribbean Sea/CONT RISE
Caribbean Sea/GAP
South Pacific/RIDGE
North Pacific/CONT RISE
North Pacific/SLOPE
South Pacific/Tasman Sea/BASIN
South Pacific/Tasman Sea/CONT RISE
South Pacific/Coral Sea/PLATEAU
Indian Ocean//RIDGE
Indian Ocean/Arabian Sea/RIDGE
Indian Ocean//PLATEAU
Antarctic Ocean/CONT RISE
North Pacific/Philippine Sea/CONT RISE
North Pacific
South Pacific/PLATEAU
South Atlantic/PLATEAU
North Atlantic/RIDGE
North Atlantic
North Atlantic/PLATEAU
North Pacific/Gulf of California/CONT RISE
South Atlantic/CONT RISE
South Atlantic/RIDGE
North Atlantic/SLOPE
South Atlantic Ocean
South Pacific Ocean
South Indian Ridge, South Indian Ocean
Indian Ocean
Gulf of Guinea
Caribbean Sea
Blake Nose, North Atlantic Ocean
Great Australian Bight
North Pacific Ocean
Walvis Ridge, Southeast Atlantic Ocean