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NARROW
Format
Article Type
Journal
Publisher
GeoRef Subject
-
all geography including DSDP/ODP Sites and Legs
-
Africa
-
North Africa
-
Morocco
-
Tarfaya Morocco (1)
-
-
Tunisia
-
El Kef Tunisia (2)
-
-
-
-
Atlantic Ocean
-
Equatorial Atlantic (1)
-
North Atlantic
-
Bay of Biscay (1)
-
Northwest Atlantic
-
Demerara Rise (1)
-
-
-
South Atlantic
-
Walvis Ridge (2)
-
-
West Atlantic (1)
-
-
Caribbean region (1)
-
Chicxulub Crater (1)
-
Europe
-
Adriatic region (1)
-
Southern Europe
-
Iberian Peninsula
-
Spain
-
Betic Cordillera (1)
-
Cantabrian Basin (1)
-
Murcia Spain
-
Caravaca Spain (2)
-
-
-
-
Italy
-
Abruzzi Italy (1)
-
Apennines
-
Central Apennines (2)
-
Northern Apennines (1)
-
-
Latium Italy (1)
-
Marches Italy (6)
-
Umbria Italy
-
Perugia Italy
-
Gubbio Italy (52)
-
Spoleto Italy (2)
-
-
Terni Italy (1)
-
-
Veneto Italy (1)
-
-
-
Western Europe
-
France
-
Alpes-de-Haute Provence France (1)
-
Aquitaine (1)
-
Paris Basin (1)
-
Pyrenees-Atlantiques France (1)
-
Seine-et-Marne France (1)
-
Vocontian Trough (1)
-
-
Scandinavia
-
Denmark
-
Stevns Klint (1)
-
-
-
United Kingdom
-
Great Britain
-
England
-
Kent England (2)
-
Sussex England
-
East Sussex England (1)
-
-
-
-
-
-
-
Indian Ocean
-
Exmouth Plateau (2)
-
Naturaliste Plateau (1)
-
-
Kerguelen Plateau (1)
-
Mediterranean region (1)
-
Mediterranean Sea
-
West Mediterranean (1)
-
-
Pacific Ocean
-
East Pacific
-
Northeast Pacific (1)
-
-
North Pacific
-
Northeast Pacific (1)
-
Northwest Pacific
-
Shatsky Rise (1)
-
-
-
West Pacific
-
Northwest Pacific
-
Shatsky Rise (1)
-
-
-
-
Raton Basin (1)
-
San Juan Basin (1)
-
Southern Ocean
-
Weddell Sea
-
Maud Rise (1)
-
-
-
United States
-
Colorado
-
Pueblo County Colorado
-
Pueblo Colorado (1)
-
-
-
Colorado Plateau (1)
-
New Mexico
-
San Juan County New Mexico (1)
-
-
-
-
commodities
-
ceramic materials (1)
-
-
elements, isotopes
-
carbon
-
C-13/C-12 (9)
-
-
halogens (1)
-
isotope ratios (9)
-
isotopes
-
radioactive isotopes
-
Re-187/Os-188 (1)
-
-
stable isotopes
-
C-13/C-12 (9)
-
He-3 (1)
-
He-4/He-3 (1)
-
O-18/O-16 (8)
-
Re-187/Os-188 (1)
-
Sr-87/Sr-86 (1)
-
-
-
metals
-
alkaline earth metals
-
strontium
-
Sr-87/Sr-86 (1)
-
-
-
gold (1)
-
platinum group
-
iridium (1)
-
osmium
-
Re-187/Os-188 (1)
-
-
palladium (1)
-
platinum (1)
-
-
rhenium
-
Re-187/Os-188 (1)
-
-
-
noble gases
-
helium
-
He-3 (1)
-
He-4/He-3 (1)
-
-
-
oxygen
-
O-18/O-16 (8)
-
-
-
fossils
-
Chordata
-
Vertebrata
-
Tetrapoda
-
Mammalia
-
Theria
-
Eutheria
-
Perissodactyla (1)
-
-
-
-
-
-
-
ichnofossils
-
Chondrites ichnofossils (2)
-
Planolites (2)
-
Thalassinoides (2)
-
Zoophycos (2)
-
-
Invertebrata
-
Echinodermata
-
Echinozoa
-
Echinoidea (1)
-
-
-
Mollusca
-
Bivalvia
-
Pterioida
-
Pteriina
-
Inocerami
-
Inoceramidae (1)
-
-
-
-
-
Cephalopoda
-
Ammonoidea
-
Ammonites (1)
-
-
-
-
Protista
-
Foraminifera
-
Rotaliina
-
Globigerinacea
-
Rotalipora (2)
-
-
-
-
Radiolaria (1)
-
Tintinnidae
-
Calpionellidae (1)
-
-
-
-
microfossils (23)
-
palynomorphs
-
Dinoflagellata (1)
-
miospores
-
pollen (1)
-
-
-
Plantae
-
algae
-
nannofossils (8)
-
-
-
thallophytes (1)
-
-
geochronology methods
-
K/Ar (1)
-
paleomagnetism (16)
-
Rb/Sr (1)
-
tephrochronology (1)
-
tree rings (1)
-
U/Pb (1)
-
-
geologic age
-
Cenozoic
-
Bronze Age (1)
-
Iron Age (1)
-
Quaternary
-
Holocene
-
upper Holocene
-
Roman period (1)
-
-
-
Pleistocene
-
lower Pleistocene (1)
-
-
-
Tertiary
-
lower Tertiary (4)
-
Neogene
-
Miocene
-
Columbia River Basalt Group (1)
-
lower Miocene
-
Aquitanian (1)
-
Burdigalian (1)
-
-
-
Pliocene (1)
-
-
Paleogene
-
Eocene
-
lower Eocene
-
Ypresian (1)
-
-
middle Eocene
-
Bartonian (1)
-
Lutetian (1)
-
-
upper Eocene
-
Priabonian (1)
-
-
-
Oligocene (1)
-
Paleocene
-
lower Paleocene
-
Danian (3)
-
K-T boundary (4)
-
-
Nacimiento Formation (1)
-
upper Paleocene (1)
-
-
Paleocene-Eocene Thermal Maximum (1)
-
-
-
-
Mesozoic
-
Cretaceous
-
Lower Cretaceous
-
Albian
-
upper Albian (1)
-
-
Aptian (1)
-
Hauterivian (1)
-
-
Upper Cretaceous
-
Campanian
-
lower Campanian (1)
-
-
Cenomanian
-
upper Cenomanian (3)
-
-
Coniacian (2)
-
Fruitland Formation (1)
-
K-T boundary (4)
-
Maestrichtian
-
lower Maestrichtian (2)
-
upper Maestrichtian (1)
-
-
Ojo Alamo Sandstone (1)
-
Santonian (3)
-
Senonian (5)
-
Turonian (7)
-
-
-
Jurassic
-
Lower Jurassic
-
Pliensbachian (1)
-
Toarcian (1)
-
-
Middle Jurassic
-
Bajocian (1)
-
-
-
Maiolica Limestone (1)
-
-
Paleozoic
-
Ordovician
-
Upper Ordovician (1)
-
-
-
-
igneous rocks
-
igneous rocks
-
volcanic rocks
-
basalts
-
flood basalts (2)
-
-
pyroclastics (1)
-
-
-
-
metamorphic rocks
-
turbidite (1)
-
-
meteorites
-
meteorites
-
micrometeorites (1)
-
stony meteorites
-
chondrites
-
ordinary chondrites
-
H chondrites (1)
-
L chondrites (1)
-
LL chondrites (1)
-
-
-
-
-
-
minerals
-
carbonates
-
calcite (1)
-
-
oxides
-
akaganeite (1)
-
chrome spinel (1)
-
hematite (1)
-
iron oxides (1)
-
magnetite (1)
-
titanomagnetite (1)
-
-
silicates
-
framework silicates
-
feldspar group
-
alkali feldspar
-
K-feldspar (1)
-
-
-
silica minerals
-
quartz (1)
-
-
-
orthosilicates
-
nesosilicates
-
zircon group
-
zircon (1)
-
-
-
-
sheet silicates
-
clay minerals
-
smectite (1)
-
-
illite (1)
-
mica group
-
biotite (2)
-
glauconite (1)
-
-
-
-
-
Primary terms
-
absolute age (2)
-
Africa
-
North Africa
-
Morocco
-
Tarfaya Morocco (1)
-
-
Tunisia
-
El Kef Tunisia (2)
-
-
-
-
asteroids (2)
-
Atlantic Ocean
-
Equatorial Atlantic (1)
-
North Atlantic
-
Bay of Biscay (1)
-
Northwest Atlantic
-
Demerara Rise (1)
-
-
-
South Atlantic
-
Walvis Ridge (2)
-
-
West Atlantic (1)
-
-
atmosphere (1)
-
biogeography (2)
-
biography (2)
-
carbon
-
C-13/C-12 (9)
-
-
Caribbean region (1)
-
catalogs (1)
-
Cenozoic
-
Bronze Age (1)
-
Iron Age (1)
-
Quaternary
-
Holocene
-
upper Holocene
-
Roman period (1)
-
-
-
Pleistocene
-
lower Pleistocene (1)
-
-
-
Tertiary
-
lower Tertiary (4)
-
Neogene
-
Miocene
-
Columbia River Basalt Group (1)
-
lower Miocene
-
Aquitanian (1)
-
Burdigalian (1)
-
-
-
Pliocene (1)
-
-
Paleogene
-
Eocene
-
lower Eocene
-
Ypresian (1)
-
-
middle Eocene
-
Bartonian (1)
-
Lutetian (1)
-
-
upper Eocene
-
Priabonian (1)
-
-
-
Oligocene (1)
-
Paleocene
-
lower Paleocene
-
Danian (3)
-
K-T boundary (4)
-
-
Nacimiento Formation (1)
-
upper Paleocene (1)
-
-
Paleocene-Eocene Thermal Maximum (1)
-
-
-
-
ceramic materials (1)
-
Chordata
-
Vertebrata
-
Tetrapoda
-
Mammalia
-
Theria
-
Eutheria
-
Perissodactyla (1)
-
-
-
-
-
-
-
clay mineralogy (1)
-
climate change (6)
-
data processing (4)
-
Deep Sea Drilling Project
-
IPOD
-
Leg 62
-
DSDP Site 465 (1)
-
-
Leg 72 (1)
-
Leg 73
-
DSDP Site 524 (1)
-
-
Leg 74
-
DSDP Site 525 (1)
-
-
Leg 80
-
DSDP Site 550 (1)
-
-
Leg 86
-
DSDP Site 577 (1)
-
-
-
Leg 22
-
DSDP Site 213 (1)
-
-
-
deformation (1)
-
diagenesis (3)
-
earthquakes (5)
-
Europe
-
Adriatic region (1)
-
Southern Europe
-
Iberian Peninsula
-
Spain
-
Betic Cordillera (1)
-
Cantabrian Basin (1)
-
Murcia Spain
-
Caravaca Spain (2)
-
-
-
-
Italy
-
Abruzzi Italy (1)
-
Apennines
-
Central Apennines (2)
-
Northern Apennines (1)
-
-
Latium Italy (1)
-
Marches Italy (6)
-
Umbria Italy
-
Perugia Italy
-
Gubbio Italy (52)
-
Spoleto Italy (2)
-
-
Terni Italy (1)
-
-
Veneto Italy (1)
-
-
-
Western Europe
-
France
-
Alpes-de-Haute Provence France (1)
-
Aquitaine (1)
-
Paris Basin (1)
-
Pyrenees-Atlantiques France (1)
-
Seine-et-Marne France (1)
-
Vocontian Trough (1)
-
-
Scandinavia
-
Denmark
-
Stevns Klint (1)
-
-
-
United Kingdom
-
Great Britain
-
England
-
Kent England (2)
-
Sussex England
-
East Sussex England (1)
-
-
-
-
-
-
-
faults (5)
-
folds (2)
-
foliation (1)
-
geochemistry (4)
-
geochronology (13)
-
geophysical methods (1)
-
ichnofossils
-
Chondrites ichnofossils (2)
-
Planolites (2)
-
Thalassinoides (2)
-
Zoophycos (2)
-
-
igneous rocks
-
volcanic rocks
-
basalts
-
flood basalts (2)
-
-
pyroclastics (1)
-
-
-
Indian Ocean
-
Exmouth Plateau (2)
-
Naturaliste Plateau (1)
-
-
Invertebrata
-
Echinodermata
-
Echinozoa
-
Echinoidea (1)
-
-
-
Mollusca
-
Bivalvia
-
Pterioida
-
Pteriina
-
Inocerami
-
Inoceramidae (1)
-
-
-
-
-
Cephalopoda
-
Ammonoidea
-
Ammonites (1)
-
-
-
-
Protista
-
Foraminifera
-
Rotaliina
-
Globigerinacea
-
Rotalipora (2)
-
-
-
-
Radiolaria (1)
-
Tintinnidae
-
Calpionellidae (1)
-
-
-
-
isotopes
-
radioactive isotopes
-
Re-187/Os-188 (1)
-
-
stable isotopes
-
C-13/C-12 (9)
-
He-3 (1)
-
He-4/He-3 (1)
-
O-18/O-16 (8)
-
Re-187/Os-188 (1)
-
Sr-87/Sr-86 (1)
-
-
-
Mediterranean region (1)
-
Mediterranean Sea
-
West Mediterranean (1)
-
-
Mesozoic
-
Cretaceous
-
Lower Cretaceous
-
Albian
-
upper Albian (1)
-
-
Aptian (1)
-
Hauterivian (1)
-
-
Upper Cretaceous
-
Campanian
-
lower Campanian (1)
-
-
Cenomanian
-
upper Cenomanian (3)
-
-
Coniacian (2)
-
Fruitland Formation (1)
-
K-T boundary (4)
-
Maestrichtian
-
lower Maestrichtian (2)
-
upper Maestrichtian (1)
-
-
Ojo Alamo Sandstone (1)
-
Santonian (3)
-
Senonian (5)
-
Turonian (7)
-
-
-
Jurassic
-
Lower Jurassic
-
Pliensbachian (1)
-
Toarcian (1)
-
-
Middle Jurassic
-
Bajocian (1)
-
-
-
Maiolica Limestone (1)
-
-
metals
-
alkaline earth metals
-
strontium
-
Sr-87/Sr-86 (1)
-
-
-
gold (1)
-
platinum group
-
iridium (1)
-
osmium
-
Re-187/Os-188 (1)
-
-
palladium (1)
-
platinum (1)
-
-
rhenium
-
Re-187/Os-188 (1)
-
-
-
meteorites
-
micrometeorites (1)
-
stony meteorites
-
chondrites
-
ordinary chondrites
-
H chondrites (1)
-
L chondrites (1)
-
LL chondrites (1)
-
-
-
-
-
noble gases
-
helium
-
He-3 (1)
-
He-4/He-3 (1)
-
-
-
Ocean Drilling Program
-
Leg 122
-
ODP Site 762 (1)
-
-
Leg 199
-
ODP Site 1215 (1)
-
-
Leg 207
-
ODP Site 1258 (1)
-
-
Leg 208
-
ODP Site 1262 (1)
-
ODP Site 1263 (1)
-
ODP Site 1264 (1)
-
ODP Site 1265 (1)
-
ODP Site 1266 (1)
-
ODP Site 1267 (1)
-
-
-
oxygen
-
O-18/O-16 (8)
-
-
Pacific Ocean
-
East Pacific
-
Northeast Pacific (1)
-
-
North Pacific
-
Northeast Pacific (1)
-
Northwest Pacific
-
Shatsky Rise (1)
-
-
-
West Pacific
-
Northwest Pacific
-
Shatsky Rise (1)
-
-
-
-
paleoclimatology (8)
-
paleoecology (5)
-
paleogeography (4)
-
paleomagnetism (16)
-
Paleozoic
-
Ordovician
-
Upper Ordovician (1)
-
-
-
palynomorphs
-
Dinoflagellata (1)
-
miospores
-
pollen (1)
-
-
-
Plantae
-
algae
-
nannofossils (8)
-
-
-
plate tectonics (2)
-
sea water (1)
-
sea-floor spreading (1)
-
sea-level changes (3)
-
sedimentary petrology (3)
-
sedimentary rocks
-
carbonate rocks
-
chalk (3)
-
limestone (9)
-
-
clastic rocks
-
bentonite (2)
-
marl (1)
-
mudstone (1)
-
red beds (1)
-
sandstone (1)
-
shale (4)
-
-
-
sedimentary structures
-
biogenic structures
-
bioturbation (2)
-
-
planar bedding structures
-
laminations (1)
-
rhythmite (2)
-
-
soft sediment deformation
-
slump structures (1)
-
-
-
sedimentation (5)
-
sediments
-
clastic sediments
-
alluvium (1)
-
clay (4)
-
dust (1)
-
gravel (1)
-
sand (2)
-
silt (1)
-
-
marine sediments (1)
-
-
slope stability (1)
-
soil mechanics (2)
-
soils (1)
-
Southern Ocean
-
Weddell Sea
-
Maud Rise (1)
-
-
-
spectroscopy (1)
-
stratigraphy (17)
-
structural analysis (2)
-
structural geology (1)
-
tectonics (5)
-
tectonophysics (1)
-
thallophytes (1)
-
thermal analysis (1)
-
United States
-
Colorado
-
Pueblo County Colorado
-
Pueblo Colorado (1)
-
-
-
Colorado Plateau (1)
-
New Mexico
-
San Juan County New Mexico (1)
-
-
-
waterways (1)
-
-
rock formations
-
Deccan Traps (2)
-
Emeishan Basalts (1)
-
Scaglia Formation (7)
-
-
sedimentary rocks
-
sedimentary rocks
-
carbonate rocks
-
chalk (3)
-
limestone (9)
-
-
clastic rocks
-
bentonite (2)
-
marl (1)
-
mudstone (1)
-
red beds (1)
-
sandstone (1)
-
shale (4)
-
-
-
turbidite (1)
-
volcaniclastics (2)
-
-
sedimentary structures
-
sedimentary structures
-
biogenic structures
-
bioturbation (2)
-
-
planar bedding structures
-
laminations (1)
-
rhythmite (2)
-
-
soft sediment deformation
-
slump structures (1)
-
-
-
-
sediments
-
sediments
-
clastic sediments
-
alluvium (1)
-
clay (4)
-
dust (1)
-
gravel (1)
-
sand (2)
-
silt (1)
-
-
marine sediments (1)
-
-
turbidite (1)
-
volcaniclastics (2)
-
-
soils
-
soils (1)
-
GeoRef Categories
Era and Period
Epoch and Age
Book Series
Date
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Perugia Italy
Nodulina kuhnti n. Sp. and nodulina eugubina n. Sp., New Agglutinated Foraminifera from the Lower Paleocene of the Scaglia Rossa, Umbria–Marche Basin, Italy Open Access
Cosmogenic 3 He anomaly K1 vs. the early Campanian isotopic event (ECE) as recorded in pelagic limestones of the Umbria-Marche succession (Italy) Available to Purchase
Temporal Variations of Seismicity Rates and Gutenberg–Richter b ‐Values for a Stochastic Declustered Catalog: An Example in Central Italy Available to Purchase
The Jurassic structural high of Sasso di Pale (Umbria-Marche Basin, Italy): How a small Apennine structure recorded Early to Middle Jurassic global perturbations Available to Purchase
ABSTRACT The reduced Jurassic sedimentary sequences deposited on a structural high in the Umbria-Marche Apennines, as well their relationships with adjacent expanded basinal sequences, have been reconstructed through detailed, interdisciplinary study of the Sasso di Pale and Monte Serrone areas near Foligno, Italy. The physiographic features of the basin originated in the Early Jurassic (latest early Pliensbachian), when extensional tectonic activity broke up a shallow water platform where the Calcare Massiccio had been deposited, and the area evolved from an edge-stepped structural high to a distally steepened ramp. The biostratigraphic framework of this paper is mainly based on calcareous nannofossils, which are a useful tool for dating condensed Jurassic successions. Although the sections studied have limited thickness and much lateral facies variation, the sedimentary evolution can be traced and interpreted within a wider Jurassic environmental perspective. In the upper Pliensbachian–lower Bajocian interval, local sea-level variations are compatible with the global sea-level curve. Furthermore, some of the characteristic events—such as the Pliensbachian–Toarcian crisis, the Early Toarcian Jenkyns Event, and the Middle Jurassic carbonate crisis—can be recognized. The present study shows how the reconstruction of local paleogeography can fit into a more general framework and how regional and global signals can be recognized even in a small structural high such as the one we have investigated.
Integrated stratigraphy of the Lutetian–Priabonian pelagic section at Bottaccione (Gubbio, central Italy): A proposal for defining and positioning the Global Stratotype Section and Point (GSSP) for the base of the Bartonian Stage (Paleogene System, Eocene Series) Available to Purchase
ABSTRACT At present, the Global Stratotype Section and Point (GSSP) for the base of the Bartonian remains the only GSSP of the Paleogene System to be defined by the International Subcommission on Paleogene Stratigraphy (ISPS) and the International Commission on Stratigraphy (ICS). Here, we present the results of an integrated, high-resolution study of calcareous plankton and benthic foraminifera biostratigraphy and a detailed magneto-, chemo-, and cyclostratigraphic analyses carried out through the upper Lutetian to the upper Priabonian pelagic sediments of the Bottaccione Gorge section near Gubbio, central Italy, to check its stratigraphic completeness and constrain in time the optimal interval for defining and positioning the GSSP for the base of the Bartonian Stage. The high-resolution and solid integrated stratigraphic framework established at Bottaccione confirmed the completeness of the section, which meets the ICS recommendations for a potential designation as a GSSP for the base of the Bartonian Stage. Thus, the Bottaccione section was compared with the parastratotype section of the Bartonian in its type area, Alum Bay, UK. On this basis, two reliable criteria for defining and positioning the Bartonian GSSP at Bottaccione are provided: (1) the base of magnetic polarity chronozone C18r as the primary correlation criterion and (2) the base of the calcareous nannofossil Dictyococcites bisectus , which defines the CNE14/CNE15 zonal boundary as a secondary correlation criterion.
The Bottaccione Gorge and Gubbio: Hypotheses for a history of the city Available to Purchase
ABSTRACT The Bottaccione Gorge at Gubbio, in central Italy, has been an important source of information about Cretaceous and Paleogene Earth history. At the much younger end of the historical continuum, it is also important for understanding the early history of Gubbio itself, for which the only written, although somewhat ambiguous, evidence comes from the Tavole eugubine, the unique bronze tablets which are a kind of Rosetta Stone for the Umbrian language. The role of the Bottaccione Gorge is debated in the history of Gubbio. The road through the gorge, crossing the Monti di Gubbio, is an important element for explaining the location of the city. One of the first settlements (late Bronze Age) is recognized from archaeological evidence at the top of a morphological fault scarp on the slope of Monte Ingino. In the Iron Age, the city described in the Tavole eugubine developed, in which Okri (fortress), Tota (city), and three sacred gates are mentioned. The locations of Okri , Tota , and the gates are still under study. According to the most likely hypothesis, Tota would have developed in the plain, on the right bank of the Torrente Camignano, while the initial settlement would have been transformed into Okri , to which the sacred gates would belong. Another gate may have been placed at the entrance to the Bottaccione Gorge. When the Eugubini (the people of Gubbio) built the new, post-Roman Gubbio in the twelfth century, they still identified, as the most suitable place for a fortified city, the location above the scarp on the slope of Monte Ingino, and they built two new gates at its lateral ends. The city was likely equipped with a third gate that faced the Bottaccione Gorge. In the thirteenth century, the Bottaccione Aqueduct was built to bring water to the highest point of Gubbio. Thus, two waterways—one natural (Torrente Camignano) and the other artificial—still branch off from Bottaccione to reach Gubbio at two different points that determine the lowest and highest levels of the city.
Evaluation of building seismic retrofitting costs founded on experimental data. The case study of “San Benedetto” School (Norcia, Italy) Available to Purchase
Small Local Earthquake Detection Using Low‐Cost MEMS Accelerometers: Examples in Northern and Central Italy Open Access
Late Cenomanian-Turonian isotopic stratigraphy in the chalk of the Paris Basin (France): a reference section between the Tethyan and Boreal realms Open Access
A review of the Earth history record in the Cretaceous, Paleogene, and Neogene pelagic carbonates of the Umbria-Marche Apennines (Italy): Twenty-five years of the Geological Observatory of Coldigioco Available to Purchase
ABSTRACT The Cretaceous and Paleogene pelagic limestone and marl formations of the Umbria-Marche Apennines of north-central Italy have proven to be exceptional recorders of the history of Earth and of life on Earth, and they have been the subject of numerous geological and paleontological studies over the last several decades. Founded a quarter century ago, in 1992, the Geological Observatory of Coldigioco is a research and teaching center focused on these exceptional rocks. This chapter is a historical introduction that briefly reviews the highlights of the lithologic, biostratigraphic, sedimentologic, magnetostratigraphic, impact-stratigraphic, geochemical, geochronological, time-scale, and cyclostratigraphical research done on the Umbria-Marche stratigraphic sequence, much of it facilitated by the Geological Observatory of Coldigioco. This review covers work up to the Coldigioco 25th anniversary Penrose conference in September 2017; it does not treat work presented at that conference or done since then. A remarkable irony is that a century ago, the Umbria-Marche Cretaceous–Paleogene sequence was so difficult to date that early work contained an error of ~35 m.y., but now there is a reasonable hope that this entire section may eventually be dated to an accuracy and precision of ~10,000 yr. This review begins with an homage to the little medieval city of Gubbio, its wild Festa dei Ceri, and its Bottaccione Gorge, where much of the research described here has been done. The review ends with three points of perspective. The first is the notion that sometimes geology can be done by looking up at the sky, and astronomy can be done by looking down at Earth, with much of the Coldigioco-based research being of this latter kind. The second is the observation that geology and paleontology are contributing far more new information to Big History—to our integrated knowledge of the past—than any other historical field in the humanities or sciences. The third is that three of the major scientific revolutions of geology in the twentieth century have direct connections to the Umbria-Marche stratigraphic sequence—the turbidite revolution, the development of plate tectonics, and the downfall of strict uniformitarianism.
Zircon provenance analysis from Lower Paleocene pelagic limestones of the Bottaccione section at Gubbio (Umbria-Marche basin, Italy) Available to Purchase
ABSTRACT Dating detrital zircon grains from sands and sandstones has become an important geological technique for determining sediment provenance and dispersal patterns. Here, we report what we believe to be the first provenance study of zircon grains extracted by dissolving large samples of pelagic limestone. Our samples come from the Paleocene section of the Umbria-Marche Apennines, Italy. Recovery of these zircon grains was a fortunate by-product of a study on chromite grains aimed to determine the kinds of meteorites that have fallen on Earth through time. The zircons we recovered included both euhedral crystals interpreted as airborne ash from volcanic eruptions of the same age as the sediment in which they were found, and rounded grains interpreted as windblown detrital material with a history of sediment transport, probably derived from desert regions. This study focuses on the rounded grains, to provide constraints on the source region from which they came. Samples from five levels in the 12 m immediately above the Cretaceous-Paleogene boundary at Gubbio, Italy, yielded detrital zircon grains with ages clustered in eight bands extending back to the Neoarchean. A previous study of this outcrop using proxies for the noncarbonate detrital content had suggested a source region for this dust either in North Africa or in Central Asia. A comparison of our dates from the actual dust grains to geochronological studies from the literature suggests source regions in North Africa and/or the Iberian Peninsula, rather than in Central Asia. In reaching this conclusion, we considered the orogenic events that may have produced each of the eight age bands, the specific source regions that may have supplied zircons from each age group, and the implications for paleoclimate (especially aridity) and paleowind conditions for the few million years just after the Cretaceous-Paleogene boundary.
A record of the micrometeorite flux during an enigmatic extraterrestrial 3 He anomaly in the Turonian (Late Cretaceous) Available to Purchase
ABSTRACT We reconstructed a record of the micrometeorite flux in the Late Cretaceous using the distribution of extraterrestrial spinel grains across an ~2 m.y. interval of elevated 3 He in the Turonian Stage (ca. 92–90 Ma). From ~30 m of the limestone succession in the Bottaccione section, Italy, a total of 979 kg of rock from levels below and within the 3 He excursion yielded 603 spinel grains (32–355 μm size). Of those, 115 represent equilibrated ordinary chondritic chromite (EC). Within the 3 He excursion, there is no change in the number of EC grains per kilogram of sediment, but H-chondritic grains dominate over L and LL grains (70%, 27%, and 3%), contrary to the interval before the excursion, where the relation between the three groups (50%, 44%, and 6%) is similar to today and to the Early Cretaceous. Intriguingly, within the 3 He anomaly, there is also a factor-of-five increase of vanadium-rich chrome spinels likely originating from achondritic and unequilibrated ordinary chondritic meteorites. The 3 He anomaly has an unusually spiky and temporal progression not readily explained by present models for delivery of extraterrestrial dust to Earth. Previous suggestions of a relation to a comet or asteroid shower possibly associated with dust-producing lunar impacts are not supported by our data. Instead, the spinel data preliminary indicate a more general disturbance of the asteroid belt, where different parent bodies or source regions of micrometeorites were affected at the same time. More spinel grains need to be recovered and more oxygen isotopic analyses of grains are required to resolve the origin of the 3 He anomaly.
What causes mass extinctions? Large asteroid/comet impacts, flood-basalt volcanism, and ocean anoxia—Correlations and cycles Available to Purchase
ABSTRACT What causes recurrent mass extinctions of life? We find that the ages of 10 of the 11 well-documented extinction episodes of the last 260 m.y. show correlations, at very high confidence (>99.99%), with the ages of the largest impact craters or the ages of massive continental flood-basalt eruptions. The four largest craters (≥100 km diameter, impact energies ≥3 × 10 7 Mt trinitrotoluene [TNT]) can be linked with recognized extinction events at 36, 66, 145, and 215 Ma, and with stratigraphic distal impact debris correlative with the extinctions. The ages of 7 out of 11 major flood-basalt episodes can be correlated with extinction events at 66, 94, ca. 120, 183, 201, 252, and 260 Ma. All seven flood-basalt–extinction co-events have coincident volcanogenic mercury anomalies in the stratigraphic record, closely linking the extinctions to the volcanism. Furthermore, the seven major periods of widespread anoxia in the oceans of the last 260 m.y. are significantly correlated (>99.99%) with the ages of the flood-basalt–extinction events, supporting a causal connection through volcanism-induced climate warming. Over Phanerozoic time (the last 541 m.y.), the six “major” mass extinctions (≥40% extinction of marine genera) are all correlated with the ages of flood-basalt episodes, and stratigraphically with related volcanogenic mercury anomalies. In only one case, the end of the Cretaceous (66 Ma), is there an apparent coincidence of a “major” mass-extinction event with both a very large crater (Chicxulub) and a continental flood-basalt eruption (the Deccan Traps). The highly significant correlations indicate that extinction episodes are typically related to severe environmental crises produced by the largest impacts and by periods of flood-basalt volcanism. About 50% of the impacts of the past 260 m.y. seem to have occurred in clusters, supporting a picture of brief pulses of increased comet or asteroid flux. The largest craters tend to fall within these age clusters. Cross-wavelet transform analyses of the ages of impact craters and extinction events show a common, strong ~26 m.y. cycle, with the most recent phase of the cycle at ~12 Ma, correlating with a minor extinction event at 11.6 Ma. The stream of life flows so slowly that the imagination fails to grasp the immensity of time required for its passage, but like many another stream it pulses irregularly as it flows. There are times of quickening, the expression points of evolution, which are almost invariably coincident with some great geologic change, and the correspondence so exact and so frequent that the laws of chance may not be invoked by way of explanation. —Richard Swann Lull ( Organic Evolution , New York, Macmillan, 1929, p. 693)
Paleoclimate implications of earliest Pleistocene tree rings from the Dunarobba Fossil Forest, Umbria, Italy Available to Purchase
ABSTRACT The earliest Pleistocene fossil forest of Dunarobba (Umbria, Italy) consists of a set of more than 70 tree trunks of an extinct species of sequoia or cypress with original cellulose still preserved. Spectral analyses of tree-ring series (325 and 448 yr in duration) combined with oxygen isotope analyses of the cellulose provide a glimpse into the mean annual temperature and the interannual climate variability that characterized this region at the beginning of the Pleistocene, when the concentration of atmospheric CO 2 was ~400 ppm. The high-frequency variability of the ring width time series shows significant spectral components that are consistent with the influence from the North Atlantic Oscillation, and to a lesser extent, solar cycles and El Niño–Southern Oscillation. The mean annual temperature estimate of ~19 °C, based on a model that combines ring widths and oxygen isotope values, is a full 6 °C warmer than the present-day value for this region. These elevated temperatures are consistent with estimates from pollen analyses and with estimates from higher latitudes.
In search of the Burdigalian GSSP: new evidence from the Contessa Section (Italy) Available to Purchase
Characterization of clays and the technology of Roman ceramics production Available to Purchase
A mandible of Tapirus arvernensis from Central Italy Available to Purchase
Guido Bonarelli and the geological discovery of the Bottaccione Gorge at Gubbio Available to Purchase
The Bottaccione Gorge at Gubbio, Italy, a source of many discoveries in Earth history, was first recognized as an outstanding geological section by Guido Bonarelli (1871–1951). Bonarelli is remembered today mainly for the meter-thick Bonarelli Level, the local manifestation of oceanic anoxic event 2 (OAE 2), which he first recognized and described. Setting aside Bonarelli’s long and distinguished career as a petroleum geologist in Borneo and Argentina, this paper concentrates on his role in the long and difficult effort to date the Scaglia rossa pelagic limestone of the Bottaccione Gorge and the surrounding Umbria-Marche Apennines. Old photographs show a barren Bottaccione Gorge a century ago; Bonarelli apparently had much better outcrops than we do today, after reforestation shortly before the middle of the twentieth century. In the absence of macrofossils, and with the inability to extract isolated foraminifera from these hard limestones, the Scaglia was dated indirectly in the late nineteenth century, and believed to be entirely of Cretaceous age, implying errors as great as 40 m.y. We can now understand why this dating seemed satisfactory at the time, because it did not conflict with Charles Lyell’s view that there should be a huge hiatus corresponding to a major faunal overturn like the Cretaceous-Paleogene (K-Pg) boundary, and because thrust faulting that contradicted it had not yet been discovered. The K-Pg boundary was correctly placed within the Scaglia in 1936 when Otto Renz identified the foraminifera in thin section. Renz wrote with pleasure of a field trip with Bonarelli, who later presented Renz’s new dating to the Società Geologica Italiana on a 1940 field trip to Gubbio. These two are the predecessors of all the geologists who have worked in the Bottaccione Gorge since the Second World War.
Otto Renz (1906–1992): Pioneer of the Cretaceous and Paleogene stratigraphy of the Central Apennines Available to Purchase
The doctoral thesis of Otto Renz on the Scaglia in the Central Apennines, published in 1936, led the foundation for the enduring fame of the region of Gubbio, Italy, as a special place to study the geohistory of the Cretaceous and the Paleogene.