Detailed geologic mapping and new SHRIMP (sensitive high-resolution ion microprobe) U-Pb zircon, Ar/Ar, Lu-Hf, 14C, luminescence (optically stimulated), thermochronology (fission-track), and palynology reveal the complex Mesoproterozoic to Quaternary geology along the ~350 km length of the Blue Ridge Parkway in Virginia. Traversing the boundary of the central and southern Appalachians, rocks along the parkway showcase the transition from the para-autochthonous Blue Ridge anticlinorium of northern and central Virginia to the allochthonous eastern Blue Ridge in southern Virginia. From mile post (MP) 0 near Waynesboro, Virginia, to ~MP 124 at Roanoke, the parkway crosses the unconformable to faulted boundary between Mesoproterozoic basement in the core of the Blue Ridge anticlinorium and Neoproterozoic to Cambrian metasedimentary and metavolcanic cover rocks on the western limb of the structure. Mesoproterozoic basement rocks comprise two groups based on SHRIMP U-Pb zircon geochronology: Group I rocks (1.2-1.14 Ga) are strongly foliated orthogneisses, and Group II rocks (1.08-1.00 Ga) are granitoids that mostly lack obvious Mesoproterozoic deformational features.Neoproterozoic to Cambrian cover rocks on the west limb of the anticlinorium include the Swift Run and Catoctin Formations, and constituent formations of the Chilhowee Group. These rocks unconformably overlie basement, or abut basement along steep reverse faults. Rocks of the Chilhowee Group are juxtaposed against Cambrian rocks of the Valley and Ridge province along southeast- and northwest-dipping, high-angle reverse faults. South of the James River (MP 64), Chilhowee Group and basement rocks occupy the hanging wall of the nearly flat-lying Blue Ridge thrust fault and associated splays.South of the Red Valley high-strain zone (MP 144.5), the parkway crosses into the wholly allochthonous eastern Blue Ridge, comprising metasedimentary and meta-igneous rocks assigned to the Wills Ridge, Ashe, and Alligator Back Formations. These rocks are bound by numerous faults, including the Rock Castle Creek fault that separates Ashe Formation rocks from Alligator Back Formation rocks in the core of the Ararat River synclinorium. The lack of unequivocal paleontologic or geochronologic ages for any of these rock sequences, combined with fundamental and conflicting differences in tectonogenetic models, compound the problem of regional correlation with Blue Ridge cover rocks to the north.The geologic transition from the central to southern Appalachians is also marked by a profound change in landscape and surficial deposits. In central Virginia, the Blue Ridge consists of narrow ridges that are held up by resistant but contrasting basement and cover lithologies. These ridges have shed eroded material from their crests to the base of the mountain fronts in the form of talus slopes, debris flows, and alluvial-colluvial fans for perhaps 10 m.y. South of Roanoke, however, ridges transition into a broad hilly plateau, flanked on the east by the Blue Ridge escarpment and the eastern Continental Divide. Here, deposits of rounded pebbles, cobbles, and boulders preserve remnants of ancestral west-flowing drainage systems.Both bedrock and surficial geologic processes provide an array of economic deposits along the length of the Blue Ridge Parkway corridor in Virginia, including base and precious metals and industrial minerals. However, common stone was the most important commodity for creating the Blue Ridge Parkway, which yielded building stone for overlooks and tunnels, or crushed stone for road base and pavement.

The siege of Petersburg and Richmond during the American Civil War in 1864–1865 provides a stellar example of how geology can affect military operations and thus the course of history. During the Union drive to take the Confederate capital, they used Virginia’s broad tidal rivers on the Atlantic Coastal Plain as supply lines for their huge army. During the siege, both sides took advantage of the unconsolidated Cenozoic sediments of the Coastal Plain to create a new style of combat—trench warfare—which would be taken to horrifying extremes in World War I. This trip visits seven sites of both historic and geological significance in the Petersburg area.

The Early Cretaceous represents a time interval in the greenhouse world that was characterized by dramatic changes in the paleogeography, paleoceanography, and paleoclimate of the Earth system. Furthermore, a striking, prominent feature of the geomagnetic polarity time scale is the ~34 m.y. period of the normal polarity field (Cretaceous Normal Polarity Superchron). Although marine anomalies and paleomagnetic data from deep-sea cores and land sections indicate that a reversed polarity (M0r) with a duration of ~0.4 m.y. occurred before the superchron, incomplete exposure, coupled with gaps in sampling due to the presence of marl layers, has limited the identification of M0r in a number of sections. An integrated multidisciplinary investigation of lower Cretaceous sediments at the base of the Poggio le Guaine (PLG) core (Northern Apennines, central Italy) was carried out to identify the Barremian-Aptian contact, which is defined by the M0r lower boundary. Rock magnetic measurements of the studied interval of the PLG core reveal magnetite as the main magnetic carrier. Paleomagnetic results indicate a short interval characterized by reverse polarity. This interval is in the uppermost part of the Hedbergella excelsa planktonic foraminiferal zone and in the upper part of the Chiastozygus litterarius (NC6) calcareous nannofossil zone. Stable carbon (δ13C) and oxygen (δ18O) isotopes indicate a chemostratigraphy of the PLG core with the signature of oceanic anoxic event 1a (OAE 1a). The lithological expression of OAE 1a is the organic-rich black shale unit known as the Selli Level. The comparison of our magnetostratigraphic, biostratigraphic, and chemostratigraphic records throughout the Barremian-Aptian boundary with those available from previously investigated oceanic and land-based sites allows recognition of the magnetochron M0r and OAE 1a at PLG for the first time.

The Contessa Valley and the Bottaccione Gorge located close to Gubbio (central Italy) include some of the most complete successions of Paleogene sediments known from the Tethyan realm. Owing to the continuous deposition in a pelagic setting, a rather modest tectonic overprint, and the availability of excellent age control through magnetostratigraphy, biostratigraphy, chronostratigraphy, and tephrostratigraphy, and direct radioisotopic dates from interbedded volcaniclastic layers, these sediments have played a prominent role in the establishment of standard Paleogene time scales. We present here a complete and well-preserved Paleogene pelagic composite succession of the Gubbio area that provides the means for a more accurate and precise calibration of the Paleogene time scale. As a necessary step toward the compilation of a more robust database on a wide scale so to improve the magnetostratigraphic, biostratigraphic, and chronostratigraphic framework of the classical Tethyan zonations, enabling regional and supraregional correlations, we have constructed a record of reliable Paleogene planktonic foraminifera, calcareous nannofossil, and dinocyst biohorizons commonly used in tropical to subtropical Cenozoic zonations. In addition, an age mode