GIS for cartographic accuracy analysis of settlements in the province of Madrid (AGE Tomas Lopez 1804).

Purpose: In this paper we study all settlements shown on the map of the Province of Madrid, sheet number 1 of AGE (Atlas Geográfico de España of Tomas Lopez 1804) and their correspondence with the current ones. This map is divided in to zones: Madrid and Almonacid de Zorita. Method: The steps followed in the methodology are as follow: 1. Geo-reference of maps with latitude and longitude framework. Move the historical longitude origin to the origin longitude of modern cartography. 2 Digitize of all population settlements or cities (97 on Madrid and 42 on Almonacid de Zorita), 3 Identify historic settlements or cities corresponding with current ones. 4. If the maps have the same orientation and scale, replace the coordinate transformation of historical settlements with a new one, by a translation in latitude and longitude equal to the calculated mean value of all ancient map points corresponding to the new. 5. Calculation of absolute accuracy of the two maps. 6 draw in the GIS, the settlements accuracy. Result: It was found that all AGE settlements have good correspondence with current, ie only 27 settlements lost in Madrid and 2 in Almonacid. The average accuracy is 2.3 and 5.7 km to Madrid and Almonacid de Zorita respectively. Discussion & Conclusion: The final accuracy map obtained shows that there is less error in the middle of the map. This study highlights the great work done by Tomas Lopez in performing this mapping without fieldwork. This demonstrates the great value that has been the work of Tomas Lopez in the history of cartography.

Population genetics of Ice Age brown bears

The Pleistocene was a dynamic period for Holarctic mammal species, complicated by episodes of glaciation, local extinctions, and intercontinental migration. The genetic consequences of these events are difficult to resolve from the study of present-day populations. To provide a direct view of population genetics in the late Pleistocene, we measured mitochondrial DNA sequence variation in seven permafrost-preserved brown bear (Ursus arctos) specimens, dated from 14,000 to 42,000 years ago. Approximately 36,000 years ago, the Beringian brown bear population had a higher genetic diversity than any extant North American population, but by 15,000 years ago genetic diversity appears similar to the modern day. The older, genetically diverse, Beringian population contained sequences from three clades now restricted to local regions within North America, indicating that current phylogeographic patterns may provide misleading data for evolutionary studies and conservation management. The late Pleistocene phylogeographic data also indicate possible colonization routes to areas south of the Cordilleran ice sheet.

(Table1) Sedimentation rates and age-control points form ODP Hole 152-919A

Planktic d18O and d13C records and point count records of biogenic, volcanic, and nonvolcanic terrigenous [ice-rafted debris (IRD)] sediment components from Hole 919A in the Irminger basin, northern North Atlantic provide a comprehensive dataset from which a paleoceanographic reconstruction for the last 630 kyr has been developed. The paleoceanographic evolution of the Irminger basin during this time contains both long-term patterns and significant developmental steps. One long-term pattern observed is the persistent deposition of hematite-stained ice-rafted debris. This record suggests that the modern and late Pleistocene discharges of icebergs from northern redbed regions to the Irminger Sea lie in the low end of the range observed over the last 630 kyr. In addition, Arctic front fluctuations appear to have been the main controlling factor on the long-term accumulation patterns of IRD and planktic biogenic groups. The Hole 919A sediment record also contains a long-term association between felsic volcanic ash abundances and light d18O excursions in both interglacial and glacial stages, which suggests a causal link between deglaciations and explosive Icelandic eruptions. A significant developmental step in the paleoceanographic reconstruction based on benthic evidence was for diminished supply of Denmark Strait Overflow Water (DSOW) beginning at ~380 ka, possibly initiated by the influx of meltwater from broad-scale iceberg discharges along the east Greenland coast. There is also planktic evidence of a two-step cooling of sea surface conditions in the Irminger basin, first at ~338-309 ka and later at ~211-190 ka, after which both glacials and interglacials were colder as the Arctic front migrated southeast of Site 919. In addition to offering these findings, this reconstruction provides a longer-term geologic context for the interpretation of more recent paleoceanographic events and patterns of deposition from this region.

(Table 1) Age of sediments with anomalously high Hg concentrations in core BDP-98, Lake Baikal

Mercury distribution was examined in the sediments of Lake Baikal that were sampled within the scope of the Baikal Drilling International Project in 1996-1999. The Hg concentrations in the ancient sediments are close to those in the modern sediments with the exception of a few peak values, whose ages coincide with those of active volcanism in adjacent areas. Mercury was demonstrated to be contained in the sediments in the adsorbed Hg0 mode, predominantly in relation with organic matter. When the organic matter of the bottom sediments is decomposed in the course of lithification, Hg is retained in the sediments adsorbed on the residual organic matter, and the concentration of this element corresponds to its initial content in the bottom sediments during their accumulation. Mercury concentrations in lithologically distinct bottom sediments of Lake Baikal and its sediments as a whole depend on the climate. Sediments that were formed during warm periods of time contain more Hg than those produced during cold periods or glaciation. Periodical variations in the Hg concentrations in the bottom sediments of Lake Baikal reflect the variations in the contents of this element in the Earth's atmosphere in the Late Cenozoic, which were, in turn, controlled by the climatic variations on the planet and, thus, can be used for detailed reconstructions of variations in the average global temperature near the planet's surface.

Revised age model of DSDP Site 95-612

Alkenone-based Cenozoic records of the partial pressure of atmospheric carbon dioxide (pCO2) are founded on the carbon isotope fractionation that occurred during marine photosynthesis (epsilon [p37:2]). However, the magnitude of epsilon [p37:2] is also influenced by phytoplankton cell size - a consideration lacking in previous alkenone-based CO2 estimates. In this study, we reconstruct cell size trends in ancient alkenone-producing coccolithophores (the reticulofenestrids) to test the influence that cell size variability played in determining epsilon [p37:2] trends and pCO2 estimates during the middle Eocene to early Miocene. At the investigated deep-sea sites, the reticulofenestrids experienced high diversity and largest mean cell sizes during the late Eocene, followed by a long-term decrease in maximum cell size since the earliest Oligocene. Decreasing haptophyte cell sizes do not account for the long-term increase in the stable carbon isotopic composition of alkenones and associated decrease in epsilon [p37:2] values during the Paleogene, supporting the conclusion that the secular pattern of epsilon [p37:2] values is primarily controlled by decreasing CO2 concentration since the earliest Oligocene. Further, given the physiology of modern alkenone producers, and considering the timings of coccolithophorid cell size change, extinctions, and changes in reconstructed pCO2 and temperature, we speculate that the selection of smaller reticulofenestrid cells during the Oligocene primarily reflects an adaptive response to increased [CO2(aq)] limitation.