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D. B. Stoeser

Publications and source records attributed to D. B. Stoeser.

At least 19 recordsLinked to original sources
USGS2022

U-Pb zircon geochronology and geological evolution of the Halaban- Al Amar region of the eastern Arabian Shield, Kingdom of Saudi Arabia.

U-Pb zircon model ages for eleven major units from the Halaban-Al Amar region of the eastern Arabian Shield indicate three stages of evolution: (1) plate convergence, (2) plate collision, and (3) post-orogenic intracratonic activity. Convergence occurred between the western Afif and eastern Ar Rayn plates that were separated by oceanic crust. Remnants of oceanic crust now comprise the ophiolitic complexes of the Urd group. The oldest plutonic unit in the study is from one of these complexes and gave an age of 694 ± 8 Ma. Detrital zircons from the sedimentary Abt formation of the Urd group, which is intercalated with the ophiolitic rocks, were derived from source rocks with a mean age of 710 Ma. The Abt formation may be an accretionary wedge on the western margin of the Ar Rayn plate. Plate convergence was terminated by collision of the Afif and Ar Rayn plates during the Al Amar orogeny which began about 670 Ma. During collision, the Urd group rocks were deformed and in part obducted on to one or both plates. Synorogenic leucogranitoid rocks were intruded from 670 to 640 Ma. From about 640 to 630 Ma, widespread unfoliated dioritic plutons were emplaced in the Ar Rayn block, and represent the end of orogenesis related to collision. There is no definitive evidence for a significantly older basement beneath the study region.

Journal of the Geological Society↗
USGS2006

Nd, Pb, Sr, and O isotopic characterization of Saudi Arabian Shield terranes

New Nd, Sr and O isotopic data for granitoid rocks of the Saudi Arabian Shield are presented together with published Nd, Pb, Sr and O isotopic data and all available geologic and geochronologic information to re-evaluate the terranes defined for the Saudi Arabian part of the Arabian-Nubian Shield. Three groups of terranes are identified: 1) the western arc terranes, 2) the eastern arc terranes, and 3) the Khida terrane. The Khida terrane is the only terrane composed of pre-Neoproterozoic continental crust. The western arc terranes are of oceanic arc affinity, and have the least radiogenic Pb and Sr and most radiogenic Nd isotopic compositions and some of the lowest ??18O values of any rocks of the Saudi Arabian Shield. Although some previous studies have characterized the eastern arc terranes as of continental affinity, this study shows that they too are composed of Neoproterozoic oceanic arcs, although their sources have slightly elevated 208Pb/204Pb, Nd, Sri, and ??18O values compared to the western arc terranes. These data suggest that either the isotopic composition of the mantle source for the western arc terranes is more depleted than that of the eastern arc terranes or the eastern arc terranes have been mixed with a small amount of cratonic source material, or both. We further elaborate on the Hulayfah-Ad Dafinah fault zone as a major boundary within the Saudi Arabian portion of the East African Orogen. With further study, its northern extension may be shown to pass through what has been defined as the Hail terrane, and its southern extension appears to lie under cover east of the Tathlith-Malahah terrane and extend into Yemen. It may represent the collision zone between East and West Gondwana, and at the very least it is an important suture between groups of arc terranes of contrasting isotopic composition caught between two converging continents.

Chemical Geology↗
USGS2001

The Khida terrane - Geology of Paleoproterozoic rocks in the Muhayil area, eastern Arabian Shield, Saudi Arabia

The bulk of the Arabian Shield of Saudi Arabia is underlain by Neoproterozoic terranes of oceanic affinity that were accreted during Pan-African time (about 680- 640Ma). Geologicalmappingandisotopicinvestigations during the 1980’s,however, provided the first evidence for Paleoproterozoic continental crust within the east- central part of the shield in Saudi Arabia. These studies delineated an older basement domain, herein referred to as the Khida terrane (Fig. l), which is defined as that part of the southern Afif composite terrane underlain by Paleoproterozoicto Archean continental crust (Stoeser and Stacey, 1988). The isotopic and geochronologic work to support our current studies within the Khida terrane are discussed in a companion abstract (Whitehouse et al., this volume). The regional geology and geochronology of the region has been summarized in detail by Johnson (1996). The current study is based on the continued use of samples previously collected in the Khida area by the authors and others as well as new field work conducted by us in 1999. This work further defines the occurrence of late Paleoproterozoic rocks at Jabal Muhayil, which is located at the eastern margin of the exposed terrane (Fig. 1). Our isotopic work is at an early stage and this abstract partly relates geologic problems that remain to be resolved.

Gondwana Research↗
USGS2001

The Khida terrane - Geochronological and isotopic evidence for Paleoproterozoic and Archean crust in the eastern Arabian Shield of Saudi Arabia

The Khida terrane of the eastern Arabian Shield of Saudi Arabia has been proposed as being underlain by Paleoproterozoic to Archean continental crust (Stoeser and Stacey, 1988). Detailed geological aspects of the Khida terrane, particularly resulting from new fieldwork during 1999, are discussed in a companion abstract (Stoeser et al., this volume). We present conventional and ion- microprobe U-Pb zircon geoenronology, Nd whole-rock, and feldspar Pb isotopic data that further elucidate the pre-Pan-African evolution of the Khida terrane. Locations for the Muhayil samples described below are shown in figure 2 of Stoeser et al. (this volume).

Gondwana Research↗
USGS2001

The Precambrian terranes of Yemen and their correlation with those of Saudi Arabia and Somalia: Implications for the accretion of Gondwana

Most of the basement of Yemen consists of early Precambrian continental high-grade terranes and Neoproterozoic low-grade island arcs that were accreted together to form an arc-continent collage during the Pan-African orogeny (Windley et al., 1996; Whitehouse et al., 1998; Whitehouse et al., in press). The suture zones between the arc and gneiss terranes are major crustal- scale tectonic boundaries. The terranes are situated east of the Nabitah suture and of the collage of low-grade, mainly island arc terranes of the Arabian Shield, but they have been reworked by a Neoproterozoic event associated with island arc accretion. Further east in Yemen are mostly unconformable, very weakly deformed and very low-grade or unmetamorphosed sediments. Thus Yemen provides key information on the broad zone of Neoproterozoic reworking associated with the collisional boundary between western and eastern Gondwana.

Gondwana Research↗
USGS2001

USGS Mineral Resources Program; national maps and datasets for research and land planning

The U.S. Geological Survey, the Nation’s leader in producing and maintaining earth science data, serves as an advisor to Congress, the Department of the Interior, and many other Federal and State agencies. Nationwide datasets that are easily available and of high quality are critical for addressing a wide range of land-planning, resource, and environmental issues. Four types of digital databases (geological, geophysical, geochemical, and mineral occurrence) are being compiled and upgraded by the Mineral Resources Program on regional and national scales to meet these needs. Where existing data are incomplete, new data are being collected to ensure national coverage. Maps and analyses produced from these databases provide basic information essential for mineral resource assessments and environmental studies, as well as fundamental information for regional and national land-use studies. Maps and analyses produced from the databases are instrumental to ongoing basic research, such as the identification of mineral deposit origins, determination of regional background values of chemical elements with known environmental impact, and study of the relationships between toxic elements or mining practices to human health. As datasets are completed or revised, the information is made available through a variety of media, including the Internet. Much of the available information is the result of cooperative activities with State and other Federal agencies. The upgraded Mineral Resources Program datasets make geologic, geophysical, geochemical, and mineral occurrence information at the state, regional, and national scales available to members of Congress, State and Federal government agencies, researchers in academia, and the general public. The status of the Mineral Resources Program datasets is outlined below.

Fact Sheet↗
USGS1989

Contrasting zircon morphology and UPb systematics in peralkaline and metaluminous post-orogenic granite complexes of the Arabian Shield, Kingdom of Saudi Arabia

Uzircon ages are reported for seven metaluminous-to-peralkaline post-orogenic granites from the Late Proterozoic Arabian Shield of Saudi Arabia. Zircons from the metaluminous rocks are prismatic, with length-to-width ratios of ∼ 2–4: 1 and small pyramidal terminations. In contrast, zircons from three of the four peralkaline complexes either lack well-developed prismatic faces (are pseudo-octahedral) or are anhedral. Some zircons from the peralkaline granites contain inherited radiogenic Pb and have very high common Pb contents ( 206 Pb/ 204 Pb < 150), making the UPb method poorly suited for determining the age of these rocks. Zircons in the metaluminous granites do not contain inheritance and yield well-defined concordia intercepts. The span of ages of the seven complexes (670-470 Ma) indicates that post-orogenic granitic magmatism was not a singular event in the Arabian Shield but rather occurred as multiple intrusive episodes from the Late Proterozoic to the Middle Ordovician.

Chemical Geology: Isotope Geoscience Section↗
USGS1988

Zircon morphology and U-Pb geochronology of seven metaluminous and peralkaline post-orogenic granite complexes of the Arabian Shield, Kingdom of Saudi Arabia

The U-Pb zircon method was used to determine the ages of seven metaluminous-to-peralkaline post-orogenic granites located throughout the Late Proterozoic Arabian Shield of Saudi Arabia. Zircons from the metaluminous rocks are prismatic, with length-to-width ratios of about 2-4:1 and small pyramidal terminations. In contrast, zircons from three of the four peralkaline complexes either lack well developed prismatic faces (are pseudo-octahedral) or are anhedral. Some of the zircons from the peralkaline granites contain inherited radiogenic lead. This complicates interpretation of the isotopic data and. in many cases, may make the U-Pb method unsuitable for determining the age of a peralkaline granite. Zircons in the metaluminous granites do not contain inheritance and thus, best-fit chords calculated through the data have upper concordia intercepts that indicate the age of intrusion, and lower intercepts that indicate simple episodic lead loss. The results show that these granites were emplaced during multiple intrusive episodes from 670 to 510 Ma (Late Proterozoic to Cambrian).

Open-File Report↗
USGS1986

Introduction

Felsic plutonic rocks ranging from dioritic to granitic in composition and from 900 to 550 Ma in age are a major component of the Arabian Shield. These rocks and the potential for associated mineralization have been extensively investigated by the Saudi Arabian Deputy Ministry for Mineral Resources during the past decade in particular. This volume describes the multidisciplinary approach which has been developed, and summarizes results. The classification, distribution, petrology, mineralogy and structure of the felsic plutonic rocks, petrogenetic and metallogenetic concepts and representative examples of mineralization are described. It is concluded that the potential for additional mineral resources is substantial.

Journal of African Earth Sciences↗
USGS1986

Guidelines to classification and nomenclature of Arabian felsic plutonic rocks

Well-defined procedures for classifying the felsic plutonic rocks of the Arabian Shield on the basis of petrographic, chemical and lithostratigraphic criteria and mineral-resource potential have been adopted and developed in the Saudi Arabian Deputy Ministry for Mineral Resources over the past decade. A number of problems with conventional classification schemes have been identified and resolved; others, notably those arising from difficulties in identifying precise mineral compositions, continue to present difficulties. The petrographic nomenclature used is essentially that recommended by the International Union of Geological Sciences. Problems that have arisen include the definition of: (1) rocks with sodic, zoned or perthitic feldspar, (2) trondhjemites, and (3) alkali granites. Chemical classification has been largely based on relative molar amounts of alumina, lime and alkalis, and the use of conventional variation diagrams, but pilot studies utilizing univariate and multivariate statistical techniques have been made. The classification used in Saudi Arabia for stratigraphic purposes is a hierarchy of formation-rank units, suites and super-suites as defined in the Saudi Arabian stratigraphic code. For genetic and petrological studies, a grouping as ‘associations’ of similar and genetically related lithologies is commonly used. In order to indicate mineral-resource potential, the felsic plutons are classed as common, precursor, specialized or mineralized, in order of increasing exploration significance.

Journal of African Earth Sciences↗
USGS1985

Reconnaissance geology of the Al Hufayr Quadrangle, sheet 27/41A, Kingdom of Saudi Arabia

The Al Hufayr quadrangle (27/41 A) lies at the northern edge of the Arabian Shield between lat 27 30' and 28 00' N. and long 41 00' and 41 30' E. A cataclastically foliated syenogranite, the oldest rock exposed in the quadrangle, crops out in a restricted area in the south-central part of the quadrangle. Younger, weakly metamorphosed metarhyolite and minor metabasalt, arkosic sandstone, and conglomerate crop out north of the syenogranite and are correlated with lithologically similar rocks exposed to the south that comprise the Hadn formation. Most of the intrusive rocks in the quadrangle are peralkaline or have a peralkaline affinity and are characterized by the presence of soda pyriboles. A large mountain known as Jibal Aja extends into the southeast corner of the quadrangle and is composed of postorogenic peralkaline alkali granite plutons that form concentric rings around a core granophyre. A small plug of Tertiary alkali basalt crops out near the southeast corner of the quadrangle. Eighty percent of the quadrangle is covered by a thick accumulation of eolian sand that forms the southern edge of the An Nafud dune field. The plutons of the Aja suite represent samples of magma that depict the evolution of a batholith-scale magma body that solidified to the Aja suite. The major- and rare-earthelement chemical variation observed among the components of the suite is a consequence of a discontinuous process that involved chemical evolution via separation of silicate liquid from earlier formed crystals, and emplacement of batches of magma, whose compositions represent stages of the process. Resource potential in the quadrangle is low. No ancient mines are reported in this quadrangle. Geochemical data for a limited number of pan concentrates of wadi sediment from wadis draining the peralkaline rocks of Jibal Aja show distinctive associations of incompatible lithophile elements. A similar association of elements has previously been shown to be diagnostic of peralkaline granite in the northeast part of the Shield but does not imply high resource potential.

Open-File Report↗